/*
    This file is part of Konsole, a terminal emulator for KDE.

    Copyright 2006-2008 by Robert Knight <robertknight@gmail.com>
    Copyright 1997,1998 by Lars Doelle <lars.doelle@on-line.de>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
    02110-1301  USA.
*/

// Own
#include "TerminalDisplay.h"

// Qt
#include <QApplication>
#include <QBoxLayout>
#include <QClipboard>
#include <QKeyEvent>
#include <QEvent>
#include <QTime>
#include <QFile>
#include <QGridLayout>
#include <QLabel>
#include <QLayout>
#include <QPainter>
#include <QPixmap>
#include <QScrollBar>
#include <QStyle>
#include <QTimer>
#include <QtDebug>
#include <QUrl>
#include <QMimeData>
#include <QDrag>

// KDE
//#include <kshell.h>
//#include <KColorScheme>
//#include <KCursor>
//#include <kdebug.h>
//#include <KLocale>
//#include <KMenu>
//#include <KNotification>
//#include <KGlobalSettings>
//#include <KShortcut>
//#include <KIO/NetAccess>

// Konsole
//#include <config-apps.h>
#include "Filter.h"
#include "konsole_wcwidth.h"
#include "ScreenWindow.h"
#include "TerminalCharacterDecoder.h"

using namespace Konsole;

#ifndef loc
#define loc(X,Y) ((Y)*_columns+(X))
#endif

#define yMouseScroll 1

#define REPCHAR   "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
                  "abcdefgjijklmnopqrstuvwxyz" \
                  "0123456789./+@"

const ColorEntry Konsole::base_color_table[TABLE_COLORS] =
// The following are almost IBM standard color codes, with some slight
// gamma correction for the dim colors to compensate for bright X screens.
// It contains the 8 ansiterm/xterm colors in 2 intensities.
{
  // Fixme: could add faint colors here, also.
  // normal
  ColorEntry(QColor(0x00,0x00,0x00), 0), ColorEntry( QColor(0xB2,0xB2,0xB2), 1), // Dfore, Dback
  ColorEntry(QColor(0x00,0x00,0x00), 0), ColorEntry( QColor(0xB2,0x18,0x18), 0), // Black, Red
  ColorEntry(QColor(0x18,0xB2,0x18), 0), ColorEntry( QColor(0xB2,0x68,0x18), 0), // Green, Yellow
  ColorEntry(QColor(0x18,0x18,0xB2), 0), ColorEntry( QColor(0xB2,0x18,0xB2), 0), // Blue, Magenta
  ColorEntry(QColor(0x18,0xB2,0xB2), 0), ColorEntry( QColor(0xB2,0xB2,0xB2), 0), // Cyan, White
  // intensiv
  ColorEntry(QColor(0x00,0x00,0x00), 0), ColorEntry( QColor(0xFF,0xFF,0xFF), 1),
  ColorEntry(QColor(0x68,0x68,0x68), 0), ColorEntry( QColor(0xFF,0x54,0x54), 0),
  ColorEntry(QColor(0x54,0xFF,0x54), 0), ColorEntry( QColor(0xFF,0xFF,0x54), 0),
  ColorEntry(QColor(0x54,0x54,0xFF), 0), ColorEntry( QColor(0xFF,0x54,0xFF), 0),
  ColorEntry(QColor(0x54,0xFF,0xFF), 0), ColorEntry( QColor(0xFF,0xFF,0xFF), 0)
};

// scroll increment used when dragging selection at top/bottom of window.

// static
bool TerminalDisplay::_antialiasText = true;
bool TerminalDisplay::HAVE_TRANSPARENCY = true;

// we use this to force QPainter to display text in LTR mode
// more information can be found in: http://unicode.org/reports/tr9/
const QChar LTR_OVERRIDE_CHAR( 0x202D );

/* ------------------------------------------------------------------------- */
/*                                                                           */
/*                                Colors                                     */
/*                                                                           */
/* ------------------------------------------------------------------------- */

/* Note that we use ANSI color order (bgr), while IBMPC color order is (rgb)

   Code        0       1       2       3       4       5       6       7
   ----------- ------- ------- ------- ------- ------- ------- ------- -------
   ANSI  (bgr) Black   Red     Green   Yellow  Blue    Magenta Cyan    White
   IBMPC (rgb) Black   Blue    Green   Cyan    Red     Magenta Yellow  White
*/

ScreenWindow* TerminalDisplay::screenWindow() const
{
    return _screenWindow;
}
void TerminalDisplay::setScreenWindow(ScreenWindow* window)
{
    // disconnect existing screen window if any
    if ( _screenWindow )
    {
        disconnect( _screenWindow , 0 , this , 0 );
    }

    _screenWindow = window;

    if ( window )
    {

// TODO: Determine if this is an issue.
//#warning "The order here is not specified - does it matter whether updateImage or updateLineProperties comes first?"
        connect( _screenWindow , SIGNAL(outputChanged()) , this , SLOT(updateLineProperties()) );
        connect( _screenWindow , SIGNAL(outputChanged()) , this , SLOT(updateImage()) );
        connect( _screenWindow , SIGNAL(outputChanged()) , this , SLOT(updateFilters()) );
        connect( _screenWindow , SIGNAL(scrolled(int)) , this , SLOT(updateFilters()) );
        window->setWindowLines(_lines);
    }
}

const ColorEntry* TerminalDisplay::colorTable() const
{
  return _colorTable;
}
void TerminalDisplay::setBackgroundColor(const QColor& color)
{
    _colorTable[DEFAULT_BACK_COLOR].color = color;
    QPalette p = palette();
      p.setColor( backgroundRole(), color );
      setPalette( p );

      // Avoid propagating the palette change to the scroll bar
      _scrollBar->setPalette( QApplication::palette() );

    update();
}
void TerminalDisplay::setForegroundColor(const QColor& color)
{
    _colorTable[DEFAULT_FORE_COLOR].color = color;

    update();
}
void TerminalDisplay::setColorTable(const ColorEntry table[])
{
  for (int i = 0; i < TABLE_COLORS; i++)
      _colorTable[i] = table[i];

  setBackgroundColor(_colorTable[DEFAULT_BACK_COLOR].color);
}

/* ------------------------------------------------------------------------- */
/*                                                                           */
/*                                   Font                                    */
/*                                                                           */
/* ------------------------------------------------------------------------- */

/*
   The VT100 has 32 special graphical characters. The usual vt100 extended
   xterm fonts have these at 0x00..0x1f.

   QT's iso mapping leaves 0x00..0x7f without any changes. But the graphicals
   come in here as proper unicode characters.

   We treat non-iso10646 fonts as VT100 extended and do the requiered mapping
   from unicode to 0x00..0x1f. The remaining translation is then left to the
   QCodec.
*/

static inline bool isLineChar(wchar_t c) { return ((c & 0xFF80) == 0x2500);}
static inline bool isLineCharString(const std::wstring& string)
{
        return (string.length() > 0) && (isLineChar(string[0]));
}


// assert for i in [0..31] : vt100extended(vt100_graphics[i]) == i.

unsigned short Konsole::vt100_graphics[32] =
{ // 0/8     1/9    2/10    3/11    4/12    5/13    6/14    7/15
  0x0020, 0x25C6, 0x2592, 0x2409, 0x240c, 0x240d, 0x240a, 0x00b0,
  0x00b1, 0x2424, 0x240b, 0x2518, 0x2510, 0x250c, 0x2514, 0x253c,
  0xF800, 0xF801, 0x2500, 0xF803, 0xF804, 0x251c, 0x2524, 0x2534,
  0x252c, 0x2502, 0x2264, 0x2265, 0x03C0, 0x2260, 0x00A3, 0x00b7
};

void TerminalDisplay::fontChange(const QFont&)
{
  QFontMetrics fm(font());
  _fontHeight = fm.height() + _lineSpacing;

  // waba TerminalDisplay 1.123:
  // "Base character width on widest ASCII character. This prevents too wide
  //  characters in the presence of double wide (e.g. Japanese) characters."
  // Get the width from representative normal width characters
  _fontWidth = qRound((double)fm.width(REPCHAR)/(double)strlen(REPCHAR));

  _fixedFont = true;

  int fw = fm.width(REPCHAR[0]);
  for(unsigned int i=1; i< strlen(REPCHAR); i++)
  {
    if (fw != fm.width(REPCHAR[i]))
    {
      _fixedFont = false;
      break;
    }
  }

  if (_fontWidth < 1)
    _fontWidth=1;

  _fontAscent = fm.ascent();

  emit changedFontMetricSignal( _fontHeight, _fontWidth );
  propagateSize();

  // We will run paint event testing procedure.
  // Although this operation will destory the orignal content,
  // the content will be drawn again after the test.
  _drawTextTestFlag = true;
  update();
}

void TerminalDisplay::calDrawTextAdditionHeight(QPainter& painter)
{
    QRect test_rect, feedback_rect;
	test_rect.setRect(1, 1, _fontWidth * 4, _fontHeight);
	painter.drawText(test_rect, Qt::AlignBottom, LTR_OVERRIDE_CHAR + QString("Mq"), &feedback_rect);

	//qDebug() << "test_rect:" << test_rect << "feeback_rect:" << feedback_rect;

	_drawTextAdditionHeight = (feedback_rect.height() - _fontHeight) / 2;
	if(_drawTextAdditionHeight < 0) {
	  _drawTextAdditionHeight = 0;
	}

	// update the original content
    _drawTextTestFlag = false;
	update();
}

void TerminalDisplay::setVTFont(const QFont& f)
{
  QFont font = f;

    // This was originally set for OS X only:
    //     mac uses floats for font width specification.
    //     this ensures the same handling for all platforms
    // but then there was revealed that various Linux distros
    // have this problem too...
    font.setStyleStrategy(QFont::ForceIntegerMetrics);

  QFontMetrics metrics(font);

  if ( !QFontInfo(font).fixedPitch() )
  {
      qDebug() << "Using a variable-width font in the terminal.  This may cause performance degradation and display/alignment errors.";
  }

  // hint that text should be drawn without anti-aliasing.
  // depending on the user's font configuration, this may not be respected
  if (!_antialiasText)
      font.setStyleStrategy( QFont::NoAntialias );

  // experimental optimization.  Konsole assumes that the terminal is using a
  // mono-spaced font, in which case kerning information should have an effect.
  // Disabling kerning saves some computation when rendering text.
  font.setKerning(false);

  QWidget::setFont(font);
  fontChange(font);
}

void TerminalDisplay::setFont(const QFont &)
{
  // ignore font change request if not coming from konsole itself
}

/* ------------------------------------------------------------------------- */
/*                                                                           */
/*                         Constructor / Destructor                          */
/*                                                                           */
/* ------------------------------------------------------------------------- */

TerminalDisplay::TerminalDisplay(QWidget *parent)
:QWidget(parent)
,_screenWindow(0)
,_allowBell(true)
,_gridLayout(0)
,_fontHeight(1)
,_fontWidth(1)
,_fontAscent(1)
,_boldIntense(true)
,_lines(1)
,_columns(1)
,_usedLines(1)
,_usedColumns(1)
,_contentHeight(1)
,_contentWidth(1)
,_image(0)
,_randomSeed(0)
,_resizing(false)
,_terminalSizeHint(false)
,_terminalSizeStartup(true)
,_bidiEnabled(false)
,_mouseMarks(false)
,_actSel(0)
,_wordSelectionMode(false)
,_lineSelectionMode(false)
,_preserveLineBreaks(false)
,_columnSelectionMode(false)
,_scrollbarLocation(QTermWidget::NoScrollBar)
,_wordCharacters(":@-./_~")
,_bellMode(SystemBeepBell)
,_blinking(false)
,_hasBlinker(false)
,_cursorBlinking(false)
,_hasBlinkingCursor(false)
,_allowBlinkingText(true)
,_ctrlDrag(false)
,_tripleClickMode(SelectWholeLine)
,_isFixedSize(false)
,_possibleTripleClick(false)
,_resizeWidget(0)
,_resizeTimer(0)
,_flowControlWarningEnabled(false)
,_outputSuspendedLabel(0)
,_lineSpacing(0)
,_colorsInverted(false)
,_blendColor(qRgba(0,0,0,0xff))
,_filterChain(new TerminalImageFilterChain())
,_cursorShape(Emulation::KeyboardCursorShape::BlockCursor)
,mMotionAfterPasting(NoMoveScreenWindow)
{
  // variables for draw text
  _drawTextAdditionHeight = 0;
  _drawTextTestFlag = false;

  // terminal applications are not designed with Right-To-Left in mind,
  // so the layout is forced to Left-To-Right
  setLayoutDirection(Qt::LeftToRight);

  // The offsets are not yet calculated.
  // Do not calculate these too often to be more smoothly when resizing
  // konsole in opaque mode.
  _topMargin = DEFAULT_TOP_MARGIN;
  _leftMargin = DEFAULT_LEFT_MARGIN;

  // create scroll bar for scrolling output up and down
  // set the scroll bar's slider to occupy the whole area of the scroll bar initially
  _scrollBar = new QScrollBar(this);
  // since the contrast with the terminal background may not be enough,
  // the scrollbar should be auto-filled if not transient
  if (!_scrollBar->style()->styleHint(QStyle::SH_ScrollBar_Transient, nullptr, _scrollBar))
    _scrollBar->setAutoFillBackground(true);
  setScroll(0,0);
  _scrollBar->setCursor( Qt::ArrowCursor );
  connect(_scrollBar, SIGNAL(valueChanged(int)), this,
                        SLOT(scrollBarPositionChanged(int)));
  // qtermwidget: we have to hide it here due the _scrollbarLocation==NoScrollBar
  // check in TerminalDisplay::setScrollBarPosition(ScrollBarPosition position)
  _scrollBar->hide();

  // setup timers for blinking cursor and text
  _blinkTimer   = new QTimer(this);
  connect(_blinkTimer, SIGNAL(timeout()), this, SLOT(blinkEvent()));
  _blinkCursorTimer   = new QTimer(this);
  connect(_blinkCursorTimer, SIGNAL(timeout()), this, SLOT(blinkCursorEvent()));

//  KCursor::setAutoHideCursor( this, true );

  setUsesMouse(true);
  setBracketedPasteMode(false);
  setColorTable(base_color_table);
  setMouseTracking(true);

  // Enable drag and drop
  setAcceptDrops(true); // attempt
  dragInfo.state = diNone;

  setFocusPolicy( Qt::WheelFocus );

  // enable input method support
  setAttribute(Qt::WA_InputMethodEnabled, true);

  // this is an important optimization, it tells Qt
  // that TerminalDisplay will handle repainting its entire area.
  setAttribute(Qt::WA_OpaquePaintEvent);

  _gridLayout = new QGridLayout(this);
  _gridLayout->setContentsMargins(0, 0, 0, 0);

  setLayout( _gridLayout );

  new AutoScrollHandler(this);
}

TerminalDisplay::~TerminalDisplay()
{
  disconnect(_blinkTimer);
  disconnect(_blinkCursorTimer);
  qApp->removeEventFilter( this );

  delete[] _image;

  delete _gridLayout;
  delete _outputSuspendedLabel;
  delete _filterChain;
}

/* ------------------------------------------------------------------------- */
/*                                                                           */
/*                             Display Operations                            */
/*                                                                           */
/* ------------------------------------------------------------------------- */

/**
 A table for emulating the simple (single width) unicode drawing chars.
 It represents the 250x - 257x glyphs. If it's zero, we can't use it.
 if it's not, it's encoded as follows: imagine a 5x5 grid where the points are numbered
 0 to 24 left to top, top to bottom. Each point is represented by the corresponding bit.

 Then, the pixels basically have the following interpretation:
 _|||_
 -...-
 -...-
 -...-
 _|||_

where _ = none
      | = vertical line.
      - = horizontal line.
 */


enum LineEncode
{
    TopL  = (1<<1),
    TopC  = (1<<2),
    TopR  = (1<<3),

    LeftT = (1<<5),
    Int11 = (1<<6),
    Int12 = (1<<7),
    Int13 = (1<<8),
    RightT = (1<<9),

    LeftC = (1<<10),
    Int21 = (1<<11),
    Int22 = (1<<12),
    Int23 = (1<<13),
    RightC = (1<<14),

    LeftB = (1<<15),
    Int31 = (1<<16),
    Int32 = (1<<17),
    Int33 = (1<<18),
    RightB = (1<<19),

    BotL  = (1<<21),
    BotC  = (1<<22),
    BotR  = (1<<23)
};

#include "LineFont.h"

static void drawLineChar(QPainter& paint, int x, int y, int w, int h, uint8_t code)
{
    //Calculate cell midpoints, end points.
    int cx = x + w/2;
    int cy = y + h/2;
    int ex = x + w - 1;
    int ey = y + h - 1;

    quint32 toDraw = LineChars[code];

    //Top _lines:
    if (toDraw & TopL)
        paint.drawLine(cx-1, y, cx-1, cy-2);
    if (toDraw & TopC)
        paint.drawLine(cx, y, cx, cy-2);
    if (toDraw & TopR)
        paint.drawLine(cx+1, y, cx+1, cy-2);

    //Bot _lines:
    if (toDraw & BotL)
        paint.drawLine(cx-1, cy+2, cx-1, ey);
    if (toDraw & BotC)
        paint.drawLine(cx, cy+2, cx, ey);
    if (toDraw & BotR)
        paint.drawLine(cx+1, cy+2, cx+1, ey);

    //Left _lines:
    if (toDraw & LeftT)
        paint.drawLine(x, cy-1, cx-2, cy-1);
    if (toDraw & LeftC)
        paint.drawLine(x, cy, cx-2, cy);
    if (toDraw & LeftB)
        paint.drawLine(x, cy+1, cx-2, cy+1);

    //Right _lines:
    if (toDraw & RightT)
        paint.drawLine(cx+2, cy-1, ex, cy-1);
    if (toDraw & RightC)
        paint.drawLine(cx+2, cy, ex, cy);
    if (toDraw & RightB)
        paint.drawLine(cx+2, cy+1, ex, cy+1);

    //Intersection points.
    if (toDraw & Int11)
        paint.drawPoint(cx-1, cy-1);
    if (toDraw & Int12)
        paint.drawPoint(cx, cy-1);
    if (toDraw & Int13)
        paint.drawPoint(cx+1, cy-1);

    if (toDraw & Int21)
        paint.drawPoint(cx-1, cy);
    if (toDraw & Int22)
        paint.drawPoint(cx, cy);
    if (toDraw & Int23)
        paint.drawPoint(cx+1, cy);

    if (toDraw & Int31)
        paint.drawPoint(cx-1, cy+1);
    if (toDraw & Int32)
        paint.drawPoint(cx, cy+1);
    if (toDraw & Int33)
        paint.drawPoint(cx+1, cy+1);

}

static void drawOtherChar(QPainter& paint, int x, int y, int w, int h, uchar code)
{
    //Calculate cell midpoints, end points.
    const int cx = x + w / 2;
    const int cy = y + h / 2;
    const int ex = x + w - 1;
    const int ey = y + h - 1;

    // Double dashes
    if (0x4C <= code && code <= 0x4F) {
        const int xHalfGap = qMax(w / 15, 1);
        const int yHalfGap = qMax(h / 15, 1);
        switch (code) {
        case 0x4D: // BOX DRAWINGS HEAVY DOUBLE DASH HORIZONTAL
            paint.drawLine(x, cy - 1, cx - xHalfGap - 1, cy - 1);
            paint.drawLine(x, cy + 1, cx - xHalfGap - 1, cy + 1);
            paint.drawLine(cx + xHalfGap, cy - 1, ex, cy - 1);
            paint.drawLine(cx + xHalfGap, cy + 1, ex, cy + 1);
            // No break!
        case 0x4C: // BOX DRAWINGS LIGHT DOUBLE DASH HORIZONTAL
            paint.drawLine(x, cy, cx - xHalfGap - 1, cy);
            paint.drawLine(cx + xHalfGap, cy, ex, cy);
            break;
        case 0x4F: // BOX DRAWINGS HEAVY DOUBLE DASH VERTICAL
            paint.drawLine(cx - 1, y, cx - 1, cy - yHalfGap - 1);
            paint.drawLine(cx + 1, y, cx + 1, cy - yHalfGap - 1);
            paint.drawLine(cx - 1, cy + yHalfGap, cx - 1, ey);
            paint.drawLine(cx + 1, cy + yHalfGap, cx + 1, ey);
            // No break!
        case 0x4E: // BOX DRAWINGS LIGHT DOUBLE DASH VERTICAL
            paint.drawLine(cx, y, cx, cy - yHalfGap - 1);
            paint.drawLine(cx, cy + yHalfGap, cx, ey);
            break;
        }
    }

    // Rounded corner characters
    else if (0x6D <= code && code <= 0x70) {
        const int r = w * 3 / 8;
        const int d = 2 * r;
        switch (code) {
        case 0x6D: // BOX DRAWINGS LIGHT ARC DOWN AND RIGHT
            paint.drawLine(cx, cy + r, cx, ey);
            paint.drawLine(cx + r, cy, ex, cy);
            paint.drawArc(cx, cy, d, d, 90 * 16, 90 * 16);
            break;
        case 0x6E: // BOX DRAWINGS LIGHT ARC DOWN AND LEFT
            paint.drawLine(cx, cy + r, cx, ey);
            paint.drawLine(x, cy, cx - r, cy);
            paint.drawArc(cx - d, cy, d, d, 0 * 16, 90 * 16);
            break;
        case 0x6F: // BOX DRAWINGS LIGHT ARC UP AND LEFT
            paint.drawLine(cx, y, cx, cy - r);
            paint.drawLine(x, cy, cx - r, cy);
            paint.drawArc(cx - d, cy - d, d, d, 270 * 16, 90 * 16);
            break;
        case 0x70: // BOX DRAWINGS LIGHT ARC UP AND RIGHT
            paint.drawLine(cx, y, cx, cy - r);
            paint.drawLine(cx + r, cy, ex, cy);
            paint.drawArc(cx, cy - d, d, d, 180 * 16, 90 * 16);
            break;
        }
    }

    // Diagonals
    else if (0x71 <= code && code <= 0x73) {
        switch (code) {
        case 0x71: // BOX DRAWINGS LIGHT DIAGONAL UPPER RIGHT TO LOWER LEFT
            paint.drawLine(ex, y, x, ey);
            break;
        case 0x72: // BOX DRAWINGS LIGHT DIAGONAL UPPER LEFT TO LOWER RIGHT
            paint.drawLine(x, y, ex, ey);
            break;
        case 0x73: // BOX DRAWINGS LIGHT DIAGONAL CROSS
            paint.drawLine(ex, y, x, ey);
            paint.drawLine(x, y, ex, ey);
            break;
        }
    }
}

void TerminalDisplay::drawLineCharString(    QPainter& painter, int x, int y, const std::wstring& str,
                                    const Character* attributes)
{
        const QPen& currentPen = painter.pen();

        if ( (attributes->rendition & RE_BOLD) && _boldIntense )
        {
            QPen boldPen(currentPen);
            boldPen.setWidth(3);
            painter.setPen( boldPen );
        }

        for (size_t i=0 ; i < str.length(); i++)
        {
            uint8_t code = static_cast<uint8_t>(str[i] & 0xffU);
            if (LineChars[code])
                drawLineChar(painter, x + (_fontWidth*i), y, _fontWidth, _fontHeight, code);
            else
                drawOtherChar(painter, x + (_fontWidth * i), y, _fontWidth, _fontHeight, code);
        }

        painter.setPen( currentPen );
}

void TerminalDisplay::setKeyboardCursorShape(QTermWidget::KeyboardCursorShape shape)
{
    _cursorShape = shape;
}
QTermWidget::KeyboardCursorShape TerminalDisplay::keyboardCursorShape() const
{
    return _cursorShape;
}
void TerminalDisplay::setKeyboardCursorColor(bool useForegroundColor, const QColor& color)
{
    if (useForegroundColor)
        _cursorColor = QColor(); // an invalid color means that
                                 // the foreground color of the
                                 // current character should
                                 // be used

    else
        _cursorColor = color;
}
QColor TerminalDisplay::keyboardCursorColor() const
{
    return _cursorColor;
}

void TerminalDisplay::setOpacity(qreal opacity)
{
    QColor color(_blendColor);
    color.setAlphaF(opacity);

    // enable automatic background filling to prevent the display
    // flickering if there is no transparency
    /*if ( color.alpha() == 255 )
    {
        setAutoFillBackground(true);
    }
    else
    {
        setAutoFillBackground(false);
    }*/

    _blendColor = color.rgba();
}

void TerminalDisplay::setBackgroundImage(QString backgroundImage)
{
    if (!backgroundImage.isEmpty())
    {
        _backgroundImage.load(backgroundImage);
        setAttribute(Qt::WA_OpaquePaintEvent, false);
    }
    else
    {
        _backgroundImage = QPixmap();
        setAttribute(Qt::WA_OpaquePaintEvent, true);
    }
}

void TerminalDisplay::drawBackground(QPainter& painter, const QRect& rect, const QColor& backgroundColor, bool useOpacitySetting )
{
        // The whole widget rectangle is filled by the background color from
        // the color scheme set in setColorTable(), while the scrollbar is
        // left to the widget style for a consistent look.
        if ( HAVE_TRANSPARENCY && qAlpha(_blendColor) < 0xff && useOpacitySetting )
        {
            if (_backgroundImage.isNull()) {
                QColor color(backgroundColor);
                color.setAlpha(qAlpha(_blendColor));

                painter.save();
                painter.setCompositionMode(QPainter::CompositionMode_Source);
                painter.fillRect(rect, color);
                painter.restore();
            }
        }
        else
            painter.fillRect(rect, backgroundColor);
}

void TerminalDisplay::drawCursor(QPainter& painter,
                                 const QRect& rect,
                                 const QColor& foregroundColor,
                                 const QColor& /*backgroundColor*/,
                                 bool& invertCharacterColor)
{
    QRect cursorRect = rect;
    cursorRect.setHeight(_fontHeight - _lineSpacing - 1);

    if (!_cursorBlinking)
    {
       if ( _cursorColor.isValid() )
           painter.setPen(_cursorColor);
       else
           painter.setPen(foregroundColor);

       if ( _cursorShape == Emulation::KeyboardCursorShape::BlockCursor )
       {
            // draw the cursor outline, adjusting the area so that
            // it is draw entirely inside 'rect'
            int penWidth = qMax(1,painter.pen().width());

            painter.drawRect(cursorRect.adjusted(penWidth/2,
                                                 penWidth/2,
                                                 - penWidth/2 - penWidth%2,
                                                 - penWidth/2 - penWidth%2));
            if ( hasFocus() )
            {
                painter.fillRect(cursorRect, _cursorColor.isValid() ? _cursorColor : foregroundColor);

                if ( !_cursorColor.isValid() )
                {
                    // invert the colour used to draw the text to ensure that the character at
                    // the cursor position is readable
                    invertCharacterColor = true;
                }
            }
       }
       else if ( _cursorShape == Emulation::KeyboardCursorShape::UnderlineCursor )
            painter.drawLine(cursorRect.left(),
                             cursorRect.bottom(),
                             cursorRect.right(),
                             cursorRect.bottom());
       else if ( _cursorShape == Emulation::KeyboardCursorShape::IBeamCursor )
            painter.drawLine(cursorRect.left(),
                             cursorRect.top(),
                             cursorRect.left(),
                             cursorRect.bottom());

    }
}

void TerminalDisplay::drawCharacters(QPainter& painter,
                                     const QRect& rect,
                                     const std::wstring& text,
                                     const Character* style,
                                     bool invertCharacterColor)
{
    // don't draw text which is currently blinking
    if ( _blinking && (style->rendition & RE_BLINK) )
        return;

    // don't draw concealed characters
    if (style->rendition & RE_CONCEAL)
            return;

    // setup bold and underline
    bool useBold = ((style->rendition & RE_BOLD) && _boldIntense) || font().bold();
    const bool useUnderline = style->rendition & RE_UNDERLINE || font().underline();
    const bool useItalic = style->rendition & RE_ITALIC || font().italic();
    const bool useStrikeOut = style->rendition & RE_STRIKEOUT || font().strikeOut();
    const bool useOverline = style->rendition & RE_OVERLINE || font().overline();

    QFont font = painter.font();
    if (    font.bold() != useBold
         || font.underline() != useUnderline
         || font.italic() != useItalic
         || font.strikeOut() != useStrikeOut
         || font.overline() != useOverline) {
       font.setBold(useBold);
       font.setUnderline(useUnderline);
       font.setItalic(useItalic);
       font.setStrikeOut(useStrikeOut);
       font.setOverline(useOverline);
       painter.setFont(font);
    }

    // setup pen
    const CharacterColor& textColor = ( invertCharacterColor ? style->backgroundColor : style->foregroundColor );
    const QColor color = textColor.color(_colorTable);
    QPen pen = painter.pen();
    if ( pen.color() != color )
    {
        pen.setColor(color);
        painter.setPen(color);
    }

    // draw text
    if ( isLineCharString(text) )
        drawLineCharString(painter,rect.x(),rect.y(),text,style);
    else
    {
        // Force using LTR as the document layout for the terminal area, because
        // there is no use cases for RTL emulator and RTL terminal application.
        //
        // This still allows RTL characters to be rendered in the RTL way.
        painter.setLayoutDirection(Qt::LeftToRight);

        if (_bidiEnabled) {
            painter.drawText(rect.x(), rect.y() + _fontAscent + _lineSpacing, QString::fromStdWString(text));
        } else {
         {
            QRect drawRect(rect.topLeft(), rect.size());
            drawRect.setHeight(rect.height() + _drawTextAdditionHeight);
            painter.drawText(drawRect, Qt::AlignBottom, LTR_OVERRIDE_CHAR + QString::fromStdWString(text));
         }
        }
    }
}

void TerminalDisplay::drawTextFragment(QPainter& painter ,
                                       const QRect& rect,
                                       const std::wstring& text,
                                       const Character* style)
{
    painter.save();

    // setup painter
    const QColor foregroundColor = style->foregroundColor.color(_colorTable);
    const QColor backgroundColor = style->backgroundColor.color(_colorTable);

    // draw background if different from the display's background color
    if ( backgroundColor != palette().background().color() )
        drawBackground(painter,rect,backgroundColor,
                       false /* do not use transparency */);

    // draw cursor shape if the current character is the cursor
    // this may alter the foreground and background colors
    bool invertCharacterColor = false;
    if ( style->rendition & RE_CURSOR )
        drawCursor(painter,rect,foregroundColor,backgroundColor,invertCharacterColor);

    // draw text
    drawCharacters(painter,rect,text,style,invertCharacterColor);

    painter.restore();
}

void TerminalDisplay::setRandomSeed(uint randomSeed) { _randomSeed = randomSeed; }
uint TerminalDisplay::randomSeed() const { return _randomSeed; }

#if 0
/*!
    Set XIM Position
*/
void TerminalDisplay::setCursorPos(const int curx, const int cury)
{
    QPoint tL  = contentsRect().topLeft();
    int    tLx = tL.x();
    int    tLy = tL.y();

    int xpos, ypos;
    ypos = _topMargin + tLy + _fontHeight*(cury-1) + _fontAscent;
    xpos = _leftMargin + tLx + _fontWidth*curx;
    //setMicroFocusHint(xpos, ypos, 0, _fontHeight); //### ???
    // fprintf(stderr, "x/y = %d/%d\txpos/ypos = %d/%d\n", curx, cury, xpos, ypos);
    _cursorLine = cury;
    _cursorCol = curx;
}
#endif

// scrolls the image by 'lines', down if lines > 0 or up otherwise.
//
// the terminal emulation keeps track of the scrolling of the character
// image as it receives input, and when the view is updated, it calls scrollImage()
// with the final scroll amount.  this improves performance because scrolling the
// display is much cheaper than re-rendering all the text for the
// part of the image which has moved up or down.
// Instead only new lines have to be drawn
void TerminalDisplay::scrollImage(int lines , const QRect& screenWindowRegion)
{
    // if the flow control warning is enabled this will interfere with the
    // scrolling optimizations and cause artifacts.  the simple solution here
    // is to just disable the optimization whilst it is visible
    if ( _outputSuspendedLabel && _outputSuspendedLabel->isVisible() )
        return;

    // constrain the region to the display
    // the bottom of the region is capped to the number of lines in the display's
    // internal image - 2, so that the height of 'region' is strictly less
    // than the height of the internal image.
    QRect region = screenWindowRegion;
    region.setBottom( qMin(region.bottom(),this->_lines-2) );

    // return if there is nothing to do
    if (    lines == 0
         || _image == 0
         || !region.isValid()
         || (region.top() + abs(lines)) >= region.bottom()
         || this->_lines <= region.height() ) return;

    // hide terminal size label to prevent it being scrolled
    if (_resizeWidget && _resizeWidget->isVisible())
        _resizeWidget->hide();

    // Note:  With Qt 4.4 the left edge of the scrolled area must be at 0
    // to get the correct (newly exposed) part of the widget repainted.
    //
    // The right edge must be before the left edge of the scroll bar to
    // avoid triggering a repaint of the entire widget, the distance is
    // given by SCROLLBAR_CONTENT_GAP
    //
    // Set the QT_FLUSH_PAINT environment variable to '1' before starting the
    // application to monitor repainting.
    //
    int scrollBarWidth = _scrollBar->isHidden() ? 0 : _scrollBar->width();
    const int SCROLLBAR_CONTENT_GAP = 1;
    QRect scrollRect;
    if ( _scrollbarLocation == QTermWidget::ScrollBarLeft )
    {
        scrollRect.setLeft(scrollBarWidth+SCROLLBAR_CONTENT_GAP);
        scrollRect.setRight(width());
    }
    else
    {
        scrollRect.setLeft(0);
        scrollRect.setRight(width() - scrollBarWidth - SCROLLBAR_CONTENT_GAP);
    }
    void* firstCharPos = &_image[ region.top() * this->_columns ];
    void* lastCharPos = &_image[ (region.top() + abs(lines)) * this->_columns ];

    int top = _topMargin + (region.top() * _fontHeight);
    int linesToMove = region.height() - abs(lines);
    int bytesToMove = linesToMove *
                      this->_columns *
                      sizeof(Character);

    Q_ASSERT( linesToMove > 0 );
    Q_ASSERT( bytesToMove > 0 );

    //scroll internal image
    if ( lines > 0 )
    {
        // check that the memory areas that we are going to move are valid
        Q_ASSERT( (char*)lastCharPos + bytesToMove <
                  (char*)(_image + (this->_lines * this->_columns)) );

        Q_ASSERT( (lines*this->_columns) < _imageSize );

        //scroll internal image down
        memmove( firstCharPos , lastCharPos , bytesToMove );

        //set region of display to scroll
        scrollRect.setTop(top);
    }
    else
    {
        // check that the memory areas that we are going to move are valid
        Q_ASSERT( (char*)firstCharPos + bytesToMove <
                  (char*)(_image + (this->_lines * this->_columns)) );

        //scroll internal image up
        memmove( lastCharPos , firstCharPos , bytesToMove );

        //set region of the display to scroll
        scrollRect.setTop(top + abs(lines) * _fontHeight);
    }
    scrollRect.setHeight(linesToMove * _fontHeight );

    Q_ASSERT(scrollRect.isValid() && !scrollRect.isEmpty());

    //scroll the display vertically to match internal _image
    scroll( 0 , _fontHeight * (-lines) , scrollRect );
}

QRegion TerminalDisplay::hotSpotRegion() const
{
    QRegion region;
    const auto hotSpots = _filterChain->hotSpots();
    for( Filter::HotSpot* const hotSpot : hotSpots )
    {
        QRect r;
        if (hotSpot->startLine()==hotSpot->endLine()) {
            r.setLeft(hotSpot->startColumn());
            r.setTop(hotSpot->startLine());
            r.setRight(hotSpot->endColumn());
            r.setBottom(hotSpot->endLine());
            region |= imageToWidget(r);;
        } else {
            r.setLeft(hotSpot->startColumn());
            r.setTop(hotSpot->startLine());
            r.setRight(_columns);
            r.setBottom(hotSpot->startLine());
            region |= imageToWidget(r);;
            for ( int line = hotSpot->startLine()+1 ; line < hotSpot->endLine() ; line++ ) {
                r.setLeft(0);
                r.setTop(line);
                r.setRight(_columns);
                r.setBottom(line);
                region |= imageToWidget(r);;
            }
            r.setLeft(0);
            r.setTop(hotSpot->endLine());
            r.setRight(hotSpot->endColumn());
            r.setBottom(hotSpot->endLine());
            region |= imageToWidget(r);;
        }
    }
    return region;
}

void TerminalDisplay::processFilters()
{
    if (!_screenWindow)
        return;

    QRegion preUpdateHotSpots = hotSpotRegion();

    // use _screenWindow->getImage() here rather than _image because
    // other classes may call processFilters() when this display's
    // ScreenWindow emits a scrolled() signal - which will happen before
    // updateImage() is called on the display and therefore _image is
    // out of date at this point
    _filterChain->setImage( _screenWindow->getImage(),
                            _screenWindow->windowLines(),
                            _screenWindow->windowColumns(),
                            _screenWindow->getLineProperties() );
    _filterChain->process();

    QRegion postUpdateHotSpots = hotSpotRegion();

    update( preUpdateHotSpots | postUpdateHotSpots );
}

void TerminalDisplay::updateImage()
{
  if ( !_screenWindow )
      return;

  // optimization - scroll the existing image where possible and
  // avoid expensive text drawing for parts of the image that
  // can simply be moved up or down
  scrollImage( _screenWindow->scrollCount() ,
               _screenWindow->scrollRegion() );
  _screenWindow->resetScrollCount();

  if (!_image) {
     // Create _image.
     // The emitted changedContentSizeSignal also leads to getImage being recreated, so do this first.
     updateImageSize();
  }

  Character* const newimg = _screenWindow->getImage();
  int lines = _screenWindow->windowLines();
  int columns = _screenWindow->windowColumns();

  setScroll( _screenWindow->currentLine() , _screenWindow->lineCount() );

  Q_ASSERT( this->_usedLines <= this->_lines );
  Q_ASSERT( this->_usedColumns <= this->_columns );

  int y,x,len;

  QPoint tL  = contentsRect().topLeft();
  int    tLx = tL.x();
  int    tLy = tL.y();
  _hasBlinker = false;

  CharacterColor cf;       // undefined
  CharacterColor _clipboard;       // undefined
  int cr  = -1;   // undefined

  const int linesToUpdate = qMin(this->_lines, qMax(0,lines  ));
  const int columnsToUpdate = qMin(this->_columns,qMax(0,columns));

  wchar_t *disstrU = new wchar_t[columnsToUpdate];
  char *dirtyMask = new char[columnsToUpdate+2];
  QRegion dirtyRegion;

  // debugging variable, this records the number of lines that are found to
  // be 'dirty' ( ie. have changed from the old _image to the new _image ) and
  // which therefore need to be repainted
  int dirtyLineCount = 0;

  for (y = 0; y < linesToUpdate; ++y)
  {
    const Character*       currentLine = &_image[y*this->_columns];
    const Character* const newLine = &newimg[y*columns];

    bool updateLine = false;

    // The dirty mask indicates which characters need repainting. We also
    // mark surrounding neighbours dirty, in case the character exceeds
    // its cell boundaries
    memset(dirtyMask, 0, columnsToUpdate+2);

    for( x = 0 ; x < columnsToUpdate ; ++x)
    {
        if ( newLine[x] != currentLine[x] )
        {
            dirtyMask[x] = true;
        }
    }

    if (!_resizing) // not while _resizing, we're expecting a paintEvent
    for (x = 0; x < columnsToUpdate; ++x)
    {
      _hasBlinker |= (newLine[x].rendition & RE_BLINK);

      // Start drawing if this character or the next one differs.
      // We also take the next one into account to handle the situation
      // where characters exceed their cell width.
      if (dirtyMask[x])
      {
        wchar_t c = newLine[x+0].character;
        if ( !c )
            continue;
        int p = 0;
        disstrU[p++] = c; //fontMap(c);
        bool lineDraw = isLineChar(c);
        bool doubleWidth = (x+1 == columnsToUpdate) ? false : (newLine[x+1].character == 0);
        cr = newLine[x].rendition;
        _clipboard = newLine[x].backgroundColor;
        if (newLine[x].foregroundColor != cf) cf = newLine[x].foregroundColor;
        int lln = columnsToUpdate - x;
        for (len = 1; len < lln; ++len)
        {
            const Character& ch = newLine[x+len];

            if (!ch.character)
                continue; // Skip trailing part of multi-col chars.

            bool nextIsDoubleWidth = (x+len+1 == columnsToUpdate) ? false : (newLine[x+len+1].character == 0);

            if (  ch.foregroundColor != cf ||
                  ch.backgroundColor != _clipboard ||
                  ch.rendition != cr ||
                  !dirtyMask[x+len] ||
                  isLineChar(c) != lineDraw ||
                  nextIsDoubleWidth != doubleWidth )
            break;

          disstrU[p++] = c; //fontMap(c);
        }

        std::wstring unistr(disstrU, p);

        bool saveFixedFont = _fixedFont;
        if (lineDraw)
           _fixedFont = false;
        if (doubleWidth)
           _fixedFont = false;

        updateLine = true;

        _fixedFont = saveFixedFont;
        x += len - 1;
      }

    }

    //both the top and bottom halves of double height _lines must always be redrawn
    //although both top and bottom halves contain the same characters, only
    //the top one is actually
    //drawn.
    if (_lineProperties.count() > y)
        updateLine |= (_lineProperties[y] & LINE_DOUBLEHEIGHT);

    // if the characters on the line are different in the old and the new _image
    // then this line must be repainted.
    if (updateLine)
    {
        dirtyLineCount++;

        // add the area occupied by this line to the region which needs to be
        // repainted
        QRect dirtyRect = QRect( _leftMargin+tLx ,
                                 _topMargin+tLy+_fontHeight*y ,
                                 _fontWidth * columnsToUpdate ,
                                 _fontHeight );

        dirtyRegion |= dirtyRect;
    }

    // replace the line of characters in the old _image with the
    // current line of the new _image
    memcpy((void*)currentLine,(const void*)newLine,columnsToUpdate*sizeof(Character));
  }

  // if the new _image is smaller than the previous _image, then ensure that the area
  // outside the new _image is cleared
  if ( linesToUpdate < _usedLines )
  {
    dirtyRegion |= QRect(   _leftMargin+tLx ,
                            _topMargin+tLy+_fontHeight*linesToUpdate ,
                            _fontWidth * this->_columns ,
                            _fontHeight * (_usedLines-linesToUpdate) );
  }
  _usedLines = linesToUpdate;

  if ( columnsToUpdate < _usedColumns )
  {
    dirtyRegion |= QRect(   _leftMargin+tLx+columnsToUpdate*_fontWidth ,
                            _topMargin+tLy ,
                            _fontWidth * (_usedColumns-columnsToUpdate) ,
                            _fontHeight * this->_lines );
  }
  _usedColumns = columnsToUpdate;

  dirtyRegion |= _inputMethodData.previousPreeditRect;

  // update the parts of the display which have changed
  update(dirtyRegion);

  if ( _hasBlinker && !_blinkTimer->isActive()) _blinkTimer->start( TEXT_BLINK_DELAY );
  if (!_hasBlinker && _blinkTimer->isActive()) { _blinkTimer->stop(); _blinking = false; }
  delete[] dirtyMask;
  delete[] disstrU;

}

void TerminalDisplay::showResizeNotification()
{
  if (_terminalSizeHint && isVisible())
  {
     if (_terminalSizeStartup) {
               _terminalSizeStartup=false;
       return;
     }
     if (!_resizeWidget)
     {
         const QString label = tr("Size: XXX x XXX");
        _resizeWidget = new QLabel(label, this);
        _resizeWidget->setMinimumWidth(_resizeWidget->fontMetrics().width(label));
        _resizeWidget->setMinimumHeight(_resizeWidget->sizeHint().height());
        _resizeWidget->setAlignment(Qt::AlignCenter);

        _resizeWidget->setStyleSheet("background-color:palette(window);border-style:solid;border-width:1px;border-color:palette(dark)");

        _resizeTimer = new QTimer(this);
        _resizeTimer->setSingleShot(true);
        connect(_resizeTimer, SIGNAL(timeout()), _resizeWidget, SLOT(hide()));
     }
     _resizeWidget->setText(tr("Size: %1 x %2").arg(_columns).arg(_lines));
     _resizeWidget->move((width()-_resizeWidget->width())/2,
                         (height()-_resizeWidget->height())/2+20);
     _resizeWidget->show();
     _resizeTimer->start(1000);
  }
}

void TerminalDisplay::setBlinkingCursor(bool blink)
{
  _hasBlinkingCursor=blink;

  if (blink && !_blinkCursorTimer->isActive())
      _blinkCursorTimer->start(QApplication::cursorFlashTime() / 2);

  if (!blink && _blinkCursorTimer->isActive())
  {
    _blinkCursorTimer->stop();
    if (_cursorBlinking)
      blinkCursorEvent();
    else
      _cursorBlinking = false;
  }
}

void TerminalDisplay::setBlinkingTextEnabled(bool blink)
{
    _allowBlinkingText = blink;

    if (blink && !_blinkTimer->isActive())
        _blinkTimer->start(TEXT_BLINK_DELAY);

    if (!blink && _blinkTimer->isActive())
    {
        _blinkTimer->stop();
        _blinking = false;
    }
}

void TerminalDisplay::focusOutEvent(QFocusEvent*)
{
    emit termLostFocus();
    // trigger a repaint of the cursor so that it is both visible (in case
    // it was hidden during blinking)
    // and drawn in a focused out state
    _cursorBlinking = false;
    updateCursor();

    _blinkCursorTimer->stop();
    if (_blinking)
        blinkEvent();

    _blinkTimer->stop();
}
void TerminalDisplay::focusInEvent(QFocusEvent*)
{
    emit termGetFocus();
    if (_hasBlinkingCursor)
    {
        _blinkCursorTimer->start();
    }
    updateCursor();

    if (_hasBlinker)
        _blinkTimer->start();
}

void TerminalDisplay::paintEvent( QPaintEvent* pe )
{
  QPainter paint(this);

  if ( !_backgroundImage.isNull() && qAlpha(_blendColor) < 0xff )
  {
    paint.drawPixmap(0, 0, _backgroundImage);
    QColor background = _colorTable[DEFAULT_BACK_COLOR].color;
    background.setAlpha(qAlpha(_blendColor));
    paint.fillRect(contentsRect(), background);
  }

  if(_drawTextTestFlag)
  {
    calDrawTextAdditionHeight(paint);
  }
  else
  {
      const auto rects = (pe->region() & contentsRect()).rects();
      for (const QRect &rect : rects)
      {
        drawBackground(paint,rect,palette().background().color(),
                       true /* use opacity setting */);
        drawContents(paint, rect);
      }
      drawInputMethodPreeditString(paint,preeditRect());
      paintFilters(paint);
  }
}

QPoint TerminalDisplay::cursorPosition() const
{
    if (_screenWindow)
        return _screenWindow->cursorPosition();
    else
        return QPoint(0,0);
}

QRect TerminalDisplay::preeditRect() const
{
    const int preeditLength = string_width(_inputMethodData.preeditString);

    if ( preeditLength == 0 )
        return QRect();

    return QRect(_leftMargin + _fontWidth*cursorPosition().x(),
                 _topMargin + _fontHeight*cursorPosition().y(),
                 _fontWidth*preeditLength,
                 _fontHeight);
}

void TerminalDisplay::drawInputMethodPreeditString(QPainter& painter , const QRect& rect)
{
    if ( _inputMethodData.preeditString.empty() )
        return;

    const QPoint cursorPos = cursorPosition();

    bool invertColors = false;
    const QColor background = _colorTable[DEFAULT_BACK_COLOR].color;
    const QColor foreground = _colorTable[DEFAULT_FORE_COLOR].color;
    const Character* style = &_image[loc(cursorPos.x(),cursorPos.y())];

    drawBackground(painter,rect,background,true);
    drawCursor(painter,rect,foreground,background,invertColors);
    drawCharacters(painter,rect,_inputMethodData.preeditString,style,invertColors);

    _inputMethodData.previousPreeditRect = rect;
}

FilterChain* TerminalDisplay::filterChain() const
{
    return _filterChain;
}

void TerminalDisplay::paintFilters(QPainter& painter)
{
    // get color of character under mouse and use it to draw
    // lines for filters
    QPoint cursorPos = mapFromGlobal(QCursor::pos());
    int cursorLine;
    int cursorColumn;
    int scrollBarWidth = (_scrollbarLocation == QTermWidget::ScrollBarLeft
                          && !_scrollBar->style()->styleHint(QStyle::SH_ScrollBar_Transient, nullptr, _scrollBar))
                         ? _scrollBar->width() : 0;

    getCharacterPosition( cursorPos , cursorLine , cursorColumn );
    Character cursorCharacter = _image[loc(cursorColumn,cursorLine)];

    painter.setPen( QPen(cursorCharacter.foregroundColor.color(colorTable())) );

    // iterate over hotspots identified by the display's currently active filters
    // and draw appropriate visuals to indicate the presence of the hotspot

    QList<Filter::HotSpot*> spots = _filterChain->hotSpots();
    QListIterator<Filter::HotSpot*> iter(spots);
    while (iter.hasNext())
    {
        Filter::HotSpot* spot = iter.next();

        QRegion region;
        if ( spot->type() == Filter::HotSpot::Link ) {
            QRect r;
            if (spot->startLine()==spot->endLine()) {
                r.setCoords( spot->startColumn()*_fontWidth + 1 + scrollBarWidth,
                             spot->startLine()*_fontHeight + 1,
                             (spot->endColumn()-1)*_fontWidth - 1 + scrollBarWidth,
                             (spot->endLine()+1)*_fontHeight - 1 );
                region |= r;
            } else {
                r.setCoords( spot->startColumn()*_fontWidth + 1 + scrollBarWidth,
                             spot->startLine()*_fontHeight + 1,
                             (_columns-1)*_fontWidth - 1 + scrollBarWidth,
                             (spot->startLine()+1)*_fontHeight - 1 );
                region |= r;
                for ( int line = spot->startLine()+1 ; line < spot->endLine() ; line++ ) {
                    r.setCoords( 0*_fontWidth + 1 + scrollBarWidth,
                                 line*_fontHeight + 1,
                                 (_columns-1)*_fontWidth - 1 + scrollBarWidth,
                                 (line+1)*_fontHeight - 1 );
                    region |= r;
                }
                r.setCoords( 0*_fontWidth + 1 + scrollBarWidth,
                             spot->endLine()*_fontHeight + 1,
                             (spot->endColumn()-1)*_fontWidth - 1 + scrollBarWidth,
                             (spot->endLine()+1)*_fontHeight - 1 );
                region |= r;
            }
        }

        for ( int line = spot->startLine() ; line <= spot->endLine() ; line++ )
        {
            int startColumn = 0;
            int endColumn = _columns-1; // TODO use number of _columns which are actually
                                        // occupied on this line rather than the width of the
                                        // display in _columns

            // ignore whitespace at the end of the lines
            while ( QChar(_image[loc(endColumn,line)].character).isSpace() && endColumn > 0 )
                endColumn--;

            // increment here because the column which we want to set 'endColumn' to
            // is the first whitespace character at the end of the line
            endColumn++;

            if ( line == spot->startLine() )
                startColumn = spot->startColumn();
            if ( line == spot->endLine() )
                endColumn = spot->endColumn();

            // subtract one pixel from
            // the right and bottom so that
            // we do not overdraw adjacent
            // hotspots
            //
            // subtracting one pixel from all sides also prevents an edge case where
            // moving the mouse outside a link could still leave it underlined
            // because the check below for the position of the cursor
            // finds it on the border of the target area
            QRect r;
            r.setCoords( startColumn*_fontWidth + 1 + scrollBarWidth,
                         line*_fontHeight + 1,
                         endColumn*_fontWidth - 1 + scrollBarWidth,
                         (line+1)*_fontHeight - 1 );
            // Underline link hotspots
            if ( spot->type() == Filter::HotSpot::Link )
            {
                QFontMetrics metrics(font());

                // find the baseline (which is the invisible line that the characters in the font sit on,
                // with some having tails dangling below)
                int baseline = r.bottom() - metrics.descent();
                // find the position of the underline below that
                int underlinePos = baseline + metrics.underlinePos();
                if ( region.contains( mapFromGlobal(QCursor::pos()) ) ){
                    painter.drawLine( r.left() , underlinePos ,
                                      r.right() , underlinePos );
                }
            }
            // Marker hotspots simply have a transparent rectanglular shape
            // drawn on top of them
            else if ( spot->type() == Filter::HotSpot::Marker )
            {
            //TODO - Do not use a hardcoded colour for this
                painter.fillRect(r,QBrush(QColor(255,0,0,120)));
            }
        }
    }
}

int TerminalDisplay::textWidth(const int startColumn, const int length, const int line) const
{
  QFontMetrics fm(font());
  int result = 0;
  for (int column = 0; column < length; column++) {
    result += fm.width(_image[loc(startColumn + column, line)].character);
  }
  return result;
}

QRect TerminalDisplay::calculateTextArea(int topLeftX, int topLeftY, int startColumn, int line, int length) {
  int left = _fixedFont ? _fontWidth * startColumn : textWidth(0, startColumn, line);
  int top = _fontHeight * line;
  int width = _fixedFont ? _fontWidth * length : textWidth(startColumn, length, line);
  return QRect(_leftMargin + topLeftX + left,
               _topMargin + topLeftY + top,
               width,
               _fontHeight);
}

void TerminalDisplay::drawContents(QPainter &paint, const QRect &rect)
{
  QPoint tL  = contentsRect().topLeft();
  int    tLx = tL.x();
  int    tLy = tL.y();

  int lux = qMin(_usedColumns-1, qMax(0,(rect.left()   - tLx - _leftMargin ) / _fontWidth));
  int luy = qMin(_usedLines-1,   qMax(0,(rect.top()    - tLy - _topMargin  ) / _fontHeight));
  int rlx = qMin(_usedColumns-1, qMax(0,(rect.right()  - tLx - _leftMargin ) / _fontWidth));
  int rly = qMin(_usedLines-1,   qMax(0,(rect.bottom() - tLy - _topMargin  ) / _fontHeight));

  const int bufferSize = _usedColumns;
  std::wstring unistr;
  unistr.reserve(bufferSize);
  for (int y = luy; y <= rly; y++)
  {
    quint32 c = _image[loc(lux,y)].character;
    int x = lux;
    if(!c && x)
      x--; // Search for start of multi-column character
    for (; x <= rlx; x++)
    {
      int len = 1;
      int p = 0;

      // reset our buffer to the maximal size
      unistr.resize(bufferSize);

      // is this a single character or a sequence of characters ?
      if ( _image[loc(x,y)].rendition & RE_EXTENDED_CHAR )
      {
        // sequence of characters
        ushort extendedCharLength = 0;
        ushort* chars = ExtendedCharTable::instance
                            .lookupExtendedChar(_image[loc(x,y)].charSequence,extendedCharLength);
        for ( int index = 0 ; index < extendedCharLength ; index++ )
        {
            Q_ASSERT( p < bufferSize );
            unistr[p++] = chars[index];
        }
      }
      else
      {
        // single character
        c = _image[loc(x,y)].character;
        if (c)
        {
             Q_ASSERT( p < bufferSize );
             unistr[p++] = c; //fontMap(c);
        }
      }

      bool lineDraw = isLineChar(c);
      bool doubleWidth = (_image[ qMin(loc(x,y)+1,_imageSize) ].character == 0);
      CharacterColor currentForeground = _image[loc(x,y)].foregroundColor;
      CharacterColor currentBackground = _image[loc(x,y)].backgroundColor;
      quint8 currentRendition = _image[loc(x,y)].rendition;

      while (x+len <= rlx &&
             _image[loc(x+len,y)].foregroundColor == currentForeground &&
             _image[loc(x+len,y)].backgroundColor == currentBackground &&
             _image[loc(x+len,y)].rendition == currentRendition &&
             (_image[ qMin(loc(x+len,y)+1,_imageSize) ].character == 0) == doubleWidth &&
             isLineChar( c = _image[loc(x+len,y)].character) == lineDraw) // Assignment!
      {
        if (c)
          unistr[p++] = c; //fontMap(c);
        if (doubleWidth) // assert((_image[loc(x+len,y)+1].character == 0)), see above if condition
          len++; // Skip trailing part of multi-column character
        len++;
      }
      if ((x+len < _usedColumns) && (!_image[loc(x+len,y)].character))
        len++; // Adjust for trailing part of multi-column character

            bool save__fixedFont = _fixedFont;
         if (lineDraw)
            _fixedFont = false;
         unistr.resize(p);

         // Create a text scaling matrix for double width and double height lines.
         QTransform textScale;

         if (y < _lineProperties.size())
         {
            if (_lineProperties[y] & LINE_DOUBLEWIDTH)
                textScale.scale(2,1);

            if (_lineProperties[y] & LINE_DOUBLEHEIGHT)
                textScale.scale(1,2);
         }

         //Apply text scaling matrix.
         paint.setWorldTransform(textScale, true);

         //calculate the area in which the text will be drawn
         QRect textArea = calculateTextArea(tLx, tLy, x, y, len);

         //move the calculated area to take account of scaling applied to the painter.
         //the position of the area from the origin (0,0) is scaled
         //by the opposite of whatever
         //transformation has been applied to the painter.  this ensures that
         //painting does actually start from textArea.topLeft()
         //(instead of textArea.topLeft() * painter-scale)
         textArea.moveTopLeft( textScale.inverted().map(textArea.topLeft()) );

         //paint text fragment
         drawTextFragment(    paint,
                            textArea,
                            unistr,
                            &_image[loc(x,y)] ); //,
                            //0,
                            //!_isPrinting );

         _fixedFont = save__fixedFont;

         //reset back to single-width, single-height _lines
         paint.setWorldTransform(textScale.inverted(), true);

         if (y < _lineProperties.size()-1)
         {
            //double-height _lines are represented by two adjacent _lines
            //containing the same characters
            //both _lines will have the LINE_DOUBLEHEIGHT attribute.
            //If the current line has the LINE_DOUBLEHEIGHT attribute,
            //we can therefore skip the next line
            if (_lineProperties[y] & LINE_DOUBLEHEIGHT)
                y++;
         }

        x += len - 1;
    }
  }
}

void TerminalDisplay::blinkEvent()
{
  if (!_allowBlinkingText) return;

  _blinking = !_blinking;

  //TODO:  Optimize to only repaint the areas of the widget
  // where there is blinking text
  // rather than repainting the whole widget.
  update();
}

QRect TerminalDisplay::imageToWidget(const QRect& imageArea) const
{
    QRect result;
    result.setLeft( _leftMargin + _fontWidth * imageArea.left() );
    result.setTop( _topMargin + _fontHeight * imageArea.top() );
    result.setWidth( _fontWidth * imageArea.width() );
    result.setHeight( _fontHeight * imageArea.height() );

    return result;
}

void TerminalDisplay::updateCursor()
{
  QRect cursorRect = imageToWidget( QRect(cursorPosition(),QSize(1,1)) );
  update(cursorRect);
}

void TerminalDisplay::blinkCursorEvent()
{
  _cursorBlinking = !_cursorBlinking;
  updateCursor();
}

/* ------------------------------------------------------------------------- */
/*                                                                           */
/*                                  Resizing                                 */
/*                                                                           */
/* ------------------------------------------------------------------------- */

void TerminalDisplay::resizeEvent(QResizeEvent*)
{
  updateImageSize();
  processFilters();
}

void TerminalDisplay::propagateSize()
{
  if (_isFixedSize)
  {
     setSize(_columns, _lines);
     QWidget::setFixedSize(sizeHint());
     parentWidget()->adjustSize();
     parentWidget()->setFixedSize(parentWidget()->sizeHint());
     return;
  }
  if (_image)
     updateImageSize();
}

void TerminalDisplay::updateImageSize()
{
  Character* oldimg = _image;
  int oldlin = _lines;
  int oldcol = _columns;

  makeImage();

  // copy the old image to reduce flicker
  int lines = qMin(oldlin,_lines);
  int columns = qMin(oldcol,_columns);

  if (oldimg)
  {
    for (int line = 0; line < lines; line++)
    {
      memcpy((void*)&_image[_columns*line],
             (void*)&oldimg[oldcol*line],columns*sizeof(Character));
    }
    delete[] oldimg;
  }

  if (_screenWindow)
      _screenWindow->setWindowLines(_lines);

  _resizing = (oldlin!=_lines) || (oldcol!=_columns);

  if ( _resizing )
  {
      showResizeNotification();
    emit changedContentSizeSignal(_contentHeight, _contentWidth); // expose resizeEvent
  }

  _resizing = false;
}

//showEvent and hideEvent are reimplemented here so that it appears to other classes that the
//display has been resized when the display is hidden or shown.
//
//TODO: Perhaps it would be better to have separate signals for show and hide instead of using
//the same signal as the one for a content size change
void TerminalDisplay::showEvent(QShowEvent*)
{
    emit changedContentSizeSignal(_contentHeight,_contentWidth);
}
void TerminalDisplay::hideEvent(QHideEvent*)
{
    emit changedContentSizeSignal(_contentHeight,_contentWidth);
}

/* ------------------------------------------------------------------------- */
/*                                                                           */
/*                                Scrollbar                                  */
/*                                                                           */
/* ------------------------------------------------------------------------- */

void TerminalDisplay::scrollBarPositionChanged(int)
{
  if ( !_screenWindow )
      return;

  _screenWindow->scrollTo( _scrollBar->value() );

  // if the thumb has been moved to the bottom of the _scrollBar then set
  // the display to automatically track new output,
  // that is, scroll down automatically
  // to how new _lines as they are added
  const bool atEndOfOutput = (_scrollBar->value() == _scrollBar->maximum());
  _screenWindow->setTrackOutput( atEndOfOutput );

  updateImage();
}

void TerminalDisplay::setScroll(int cursor, int slines)
{
  // update _scrollBar if the range or value has changed,
  // otherwise return
  //
  // setting the range or value of a _scrollBar will always trigger
  // a repaint, so it should be avoided if it is not necessary
  if ( _scrollBar->minimum() == 0                 &&
       _scrollBar->maximum() == (slines - _lines) &&
       _scrollBar->value()   == cursor )
  {
        return;
  }

  disconnect(_scrollBar, SIGNAL(valueChanged(int)), this, SLOT(scrollBarPositionChanged(int)));
  _scrollBar->setRange(0,slines - _lines);
  _scrollBar->setSingleStep(1);
  _scrollBar->setPageStep(_lines);
  _scrollBar->setValue(cursor);
  connect(_scrollBar, SIGNAL(valueChanged(int)), this, SLOT(scrollBarPositionChanged(int)));
}

void TerminalDisplay::scrollToEnd()
{
  disconnect(_scrollBar, SIGNAL(valueChanged(int)), this, SLOT(scrollBarPositionChanged(int)));
  _scrollBar->setValue( _scrollBar->maximum() );
  connect(_scrollBar, SIGNAL(valueChanged(int)), this, SLOT(scrollBarPositionChanged(int)));

  _screenWindow->scrollTo( _scrollBar->value() + 1 );
  _screenWindow->setTrackOutput( _screenWindow->atEndOfOutput() );
}

void TerminalDisplay::setScrollBarPosition(QTermWidget::ScrollBarPosition position)
{
  if (_scrollbarLocation == position)
      return;

  if ( position == QTermWidget::NoScrollBar )
     _scrollBar->hide();
  else
     _scrollBar->show();

  _topMargin = _leftMargin = 1;
  _scrollbarLocation = position;

  propagateSize();
  update();
}

void TerminalDisplay::mousePressEvent(QMouseEvent* ev)
{
  if ( _possibleTripleClick && (ev->button()==Qt::LeftButton) ) {
    mouseTripleClickEvent(ev);
    return;
  }

  if ( !contentsRect().contains(ev->pos()) ) return;

  if ( !_screenWindow ) return;

  int charLine;
  int charColumn;
  getCharacterPosition(ev->pos(),charLine,charColumn);
  QPoint pos = QPoint(charColumn,charLine);

  if ( ev->button() == Qt::LeftButton)
  {
    _lineSelectionMode = false;
    _wordSelectionMode = false;

    emit isBusySelecting(true); // Keep it steady...
    // Drag only when the Control key is hold
    bool selected = false;

    // The receiver of the testIsSelected() signal will adjust
    // 'selected' accordingly.
    //emit testIsSelected(pos.x(), pos.y(), selected);

    selected =  _screenWindow->isSelected(pos.x(),pos.y());

    if ((!_ctrlDrag || ev->modifiers() & Qt::ControlModifier) && selected ) {
      // The user clicked inside selected text
      dragInfo.state = diPending;
      dragInfo.start = ev->pos();
    }
    else {
      // No reason to ever start a drag event
      dragInfo.state = diNone;

      _preserveLineBreaks = !( ( ev->modifiers() & Qt::ControlModifier ) && !(ev->modifiers() & Qt::AltModifier) );
      _columnSelectionMode = (ev->modifiers() & Qt::AltModifier) && (ev->modifiers() & Qt::ControlModifier);

      if (_mouseMarks || (ev->modifiers() & Qt::ShiftModifier))
      {
         _screenWindow->clearSelection();

        //emit clearSelectionSignal();
        pos.ry() += _scrollBar->value();
        _iPntSel = _pntSel = pos;
        _actSel = 1; // left mouse button pressed but nothing selected yet.

      }
      else
      {
        emit mouseSignal( 0, charColumn + 1, charLine + 1 +_scrollBar->value() -_scrollBar->maximum() , 0);
      }

      Filter::HotSpot *spot = _filterChain->hotSpotAt(charLine, charColumn);
      if (spot && spot->type() == Filter::HotSpot::Link)
          spot->activate("click-action");
    }
  }
  else if ( ev->button() == Qt::MidButton )
  {
    if ( _mouseMarks || (ev->modifiers() & Qt::ShiftModifier) )
      emitSelection(true,ev->modifiers() & Qt::ControlModifier);
    else
      emit mouseSignal( 1, charColumn +1, charLine +1 +_scrollBar->value() -_scrollBar->maximum() , 0);
  }
  else if ( ev->button() == Qt::RightButton )
  {
    if (_mouseMarks || (ev->modifiers() & Qt::ShiftModifier))
        emit configureRequest(ev->pos());
    else
        emit mouseSignal( 2, charColumn +1, charLine +1 +_scrollBar->value() -_scrollBar->maximum() , 0);
  }
}

QList<QAction*> TerminalDisplay::filterActions(const QPoint& position)
{
  int charLine, charColumn;
  getCharacterPosition(position,charLine,charColumn);

  Filter::HotSpot* spot = _filterChain->hotSpotAt(charLine,charColumn);

  return spot ? spot->actions() : QList<QAction*>();
}

void TerminalDisplay::mouseMoveEvent(QMouseEvent* ev)
{
  int charLine = 0;
  int charColumn = 0;
  int scrollBarWidth = (_scrollbarLocation == QTermWidget::ScrollBarLeft
                        && !_scrollBar->style()->styleHint(QStyle::SH_ScrollBar_Transient, nullptr, _scrollBar))
                       ? _scrollBar->width() : 0;

  getCharacterPosition(ev->pos(),charLine,charColumn);

  // handle filters
  // change link hot-spot appearance on mouse-over
  Filter::HotSpot* spot = _filterChain->hotSpotAt(charLine,charColumn);
  if ( spot && spot->type() == Filter::HotSpot::Link)
  {
    QRegion previousHotspotArea = _mouseOverHotspotArea;
    _mouseOverHotspotArea = QRegion();
    QRect r;
    if (spot->startLine()==spot->endLine()) {
        r.setCoords( spot->startColumn()*_fontWidth + scrollBarWidth,
                     spot->startLine()*_fontHeight,
                     spot->endColumn()*_fontWidth + scrollBarWidth,
                     (spot->endLine()+1)*_fontHeight - 1 );
        _mouseOverHotspotArea |= r;
    } else {
        r.setCoords( spot->startColumn()*_fontWidth + scrollBarWidth,
                     spot->startLine()*_fontHeight,
                     _columns*_fontWidth - 1 + scrollBarWidth,
                     (spot->startLine()+1)*_fontHeight );
        _mouseOverHotspotArea |= r;
        for ( int line = spot->startLine()+1 ; line < spot->endLine() ; line++ ) {
            r.setCoords( 0*_fontWidth + scrollBarWidth,
                         line*_fontHeight,
                         _columns*_fontWidth + scrollBarWidth,
                         (line+1)*_fontHeight );
            _mouseOverHotspotArea |= r;
        }
        r.setCoords( 0*_fontWidth + scrollBarWidth,
                     spot->endLine()*_fontHeight,
                     spot->endColumn()*_fontWidth + scrollBarWidth,
                     (spot->endLine()+1)*_fontHeight );
        _mouseOverHotspotArea |= r;
    }

    update( _mouseOverHotspotArea | previousHotspotArea );
  }
  else if ( !_mouseOverHotspotArea.isEmpty() )
  {
        update( _mouseOverHotspotArea );
        // set hotspot area to an invalid rectangle
        _mouseOverHotspotArea = QRegion();
  }

  // for auto-hiding the cursor, we need mouseTracking
  if (ev->buttons() == Qt::NoButton ) return;

  // if the terminal is interested in mouse movements
  // then emit a mouse movement signal, unless the shift
  // key is being held down, which overrides this.
  if (!_mouseMarks && !(ev->modifiers() & Qt::ShiftModifier))
  {
    int button = 3;
    if (ev->buttons() & Qt::LeftButton)
        button = 0;
    if (ev->buttons() & Qt::MidButton)
        button = 1;
    if (ev->buttons() & Qt::RightButton)
        button = 2;


        emit mouseSignal( button,
                        charColumn + 1,
                        charLine + 1 +_scrollBar->value() -_scrollBar->maximum(),
             1 );

    return;
  }

  if (dragInfo.state == diPending)
  {
    // we had a mouse down, but haven't confirmed a drag yet
    // if the mouse has moved sufficiently, we will confirm

//   int distance = KGlobalSettings::dndEventDelay();
   int distance = QApplication::startDragDistance();
   if ( ev->x() > dragInfo.start.x() + distance || ev->x() < dragInfo.start.x() - distance ||
        ev->y() > dragInfo.start.y() + distance || ev->y() < dragInfo.start.y() - distance)
   {
      // we've left the drag square, we can start a real drag operation now
      emit isBusySelecting(false); // Ok.. we can breath again.

       _screenWindow->clearSelection();
      doDrag();
    }
    return;
  }
  else if (dragInfo.state == diDragging)
  {
    // this isn't technically needed because mouseMoveEvent is suppressed during
    // Qt drag operations, replaced by dragMoveEvent
    return;
  }

  if (_actSel == 0) return;

 // don't extend selection while pasting
  if (ev->buttons() & Qt::MidButton) return;

  extendSelection( ev->pos() );
}

void TerminalDisplay::extendSelection( const QPoint& position )
{
  QPoint pos = position;

  if ( !_screenWindow )
      return;

  //if ( !contentsRect().contains(ev->pos()) ) return;
  QPoint tL  = contentsRect().topLeft();
  int    tLx = tL.x();
  int    tLy = tL.y();
  int    scroll = _scrollBar->value();

  // we're in the process of moving the mouse with the left button pressed
  // the mouse cursor will kept caught within the bounds of the text in
  // this widget.

  int linesBeyondWidget = 0;

  QRect textBounds(tLx + _leftMargin,
                     tLy + _topMargin,
                   _usedColumns*_fontWidth-1,
                   _usedLines*_fontHeight-1);

  // Adjust position within text area bounds.
  QPoint oldpos = pos;

  pos.setX( qBound(textBounds.left(),pos.x(),textBounds.right()) );
  pos.setY( qBound(textBounds.top(),pos.y(),textBounds.bottom()) );

  if ( oldpos.y() > textBounds.bottom() )
  {
      linesBeyondWidget = (oldpos.y()-textBounds.bottom()) / _fontHeight;
    _scrollBar->setValue(_scrollBar->value()+linesBeyondWidget+1); // scrollforward
  }
  if ( oldpos.y() < textBounds.top() )
  {
      linesBeyondWidget = (textBounds.top()-oldpos.y()) / _fontHeight;
    _scrollBar->setValue(_scrollBar->value()-linesBeyondWidget-1); // history
  }

  int charColumn = 0;
  int charLine = 0;
  getCharacterPosition(pos,charLine,charColumn);

  QPoint here = QPoint(charColumn,charLine); //QPoint((pos.x()-tLx-_leftMargin+(_fontWidth/2))/_fontWidth,(pos.y()-tLy-_topMargin)/_fontHeight);
  QPoint ohere;
  QPoint _iPntSelCorr = _iPntSel;
  _iPntSelCorr.ry() -= _scrollBar->value();
  QPoint _pntSelCorr = _pntSel;
  _pntSelCorr.ry() -= _scrollBar->value();
  bool swapping = false;

  if ( _wordSelectionMode )
  {
    // Extend to word boundaries
    int i;
    QChar selClass;

    bool left_not_right = ( here.y() < _iPntSelCorr.y() ||
       ( here.y() == _iPntSelCorr.y() && here.x() < _iPntSelCorr.x() ) );
    bool old_left_not_right = ( _pntSelCorr.y() < _iPntSelCorr.y() ||
       ( _pntSelCorr.y() == _iPntSelCorr.y() && _pntSelCorr.x() < _iPntSelCorr.x() ) );
    swapping = left_not_right != old_left_not_right;

    // Find left (left_not_right ? from here : from start)
    QPoint left = left_not_right ? here : _iPntSelCorr;
    i = loc(left.x(),left.y());
    if (i>=0 && i<=_imageSize) {
      selClass = charClass(_image[i].character);
      while ( ((left.x()>0) || (left.y()>0 && (_lineProperties[left.y()-1] & LINE_WRAPPED) ))
                      && charClass(_image[i-1].character) == selClass )
      { i--; if (left.x()>0) left.rx()--; else {left.rx()=_usedColumns-1; left.ry()--;} }
    }

    // Find left (left_not_right ? from start : from here)
    QPoint right = left_not_right ? _iPntSelCorr : here;
    i = loc(right.x(),right.y());
    if (i>=0 && i<=_imageSize) {
      selClass = charClass(_image[i].character);
      while( ((right.x()<_usedColumns-1) || (right.y()<_usedLines-1 && (_lineProperties[right.y()] & LINE_WRAPPED) ))
                      && charClass(_image[i+1].character) == selClass )
      { i++; if (right.x()<_usedColumns-1) right.rx()++; else {right.rx()=0; right.ry()++; } }
    }

    // Pick which is start (ohere) and which is extension (here)
    if ( left_not_right )
    {
      here = left; ohere = right;
    }
    else
    {
      here = right; ohere = left;
    }
    ohere.rx()++;
  }

  if ( _lineSelectionMode )
  {
    // Extend to complete line
    bool above_not_below = ( here.y() < _iPntSelCorr.y() );

    QPoint above = above_not_below ? here : _iPntSelCorr;
    QPoint below = above_not_below ? _iPntSelCorr : here;

    while (above.y()>0 && (_lineProperties[above.y()-1] & LINE_WRAPPED) )
      above.ry()--;
    while (below.y()<_usedLines-1 && (_lineProperties[below.y()] & LINE_WRAPPED) )
      below.ry()++;

    above.setX(0);
    below.setX(_usedColumns-1);

    // Pick which is start (ohere) and which is extension (here)
    if ( above_not_below )
    {
      here = above; ohere = below;
    }
    else
    {
      here = below; ohere = above;
    }

    QPoint newSelBegin = QPoint( ohere.x(), ohere.y() );
    swapping = !(_tripleSelBegin==newSelBegin);
    _tripleSelBegin = newSelBegin;

    ohere.rx()++;
  }

  int offset = 0;
  if ( !_wordSelectionMode && !_lineSelectionMode )
  {
    int i;
    QChar selClass;

    bool left_not_right = ( here.y() < _iPntSelCorr.y() ||
       ( here.y() == _iPntSelCorr.y() && here.x() < _iPntSelCorr.x() ) );
    bool old_left_not_right = ( _pntSelCorr.y() < _iPntSelCorr.y() ||
       ( _pntSelCorr.y() == _iPntSelCorr.y() && _pntSelCorr.x() < _iPntSelCorr.x() ) );
    swapping = left_not_right != old_left_not_right;

    // Find left (left_not_right ? from here : from start)
    QPoint left = left_not_right ? here : _iPntSelCorr;

    // Find left (left_not_right ? from start : from here)
    QPoint right = left_not_right ? _iPntSelCorr : here;
    if ( right.x() > 0 && !_columnSelectionMode )
    {
      i = loc(right.x(),right.y());
      if (i>=0 && i<=_imageSize) {
        selClass = charClass(_image[i-1].character);
       /* if (selClass == ' ')
        {
          while ( right.x() < _usedColumns-1 && charClass(_image[i+1].character) == selClass && (right.y()<_usedLines-1) &&
                          !(_lineProperties[right.y()] & LINE_WRAPPED))
          { i++; right.rx()++; }
          if (right.x() < _usedColumns-1)
            right = left_not_right ? _iPntSelCorr : here;
          else
            right.rx()++;  // will be balanced later because of offset=-1;
        }*/
      }
    }

    // Pick which is start (ohere) and which is extension (here)
    if ( left_not_right )
    {
      here = left; ohere = right; offset = 0;
    }
    else
    {
      here = right; ohere = left; offset = -1;
    }
  }

  if ((here == _pntSelCorr) && (scroll == _scrollBar->value())) return; // not moved

  if (here == ohere) return; // It's not left, it's not right.

  if ( _actSel < 2 || swapping )
  {
    if ( _columnSelectionMode && !_lineSelectionMode && !_wordSelectionMode )
    {
        _screenWindow->setSelectionStart( ohere.x() , ohere.y() , true );
    }
    else
    {
        _screenWindow->setSelectionStart( ohere.x()-1-offset , ohere.y() , false );
    }

  }

  _actSel = 2; // within selection
  _pntSel = here;
  _pntSel.ry() += _scrollBar->value();

  if ( _columnSelectionMode && !_lineSelectionMode && !_wordSelectionMode )
  {
     _screenWindow->setSelectionEnd( here.x() , here.y() );
  }
  else
  {
     _screenWindow->setSelectionEnd( here.x()+offset , here.y() );
  }

}

void TerminalDisplay::mouseReleaseEvent(QMouseEvent* ev)
{
    if ( !_screenWindow )
        return;

    int charLine;
    int charColumn;
    getCharacterPosition(ev->pos(),charLine,charColumn);

  if ( ev->button() == Qt::LeftButton)
  {
    emit isBusySelecting(false);
    if(dragInfo.state == diPending)
    {
      // We had a drag event pending but never confirmed.  Kill selection
       _screenWindow->clearSelection();
      //emit clearSelectionSignal();
    }
    else
    {
      if ( _actSel > 1 )
      {
          setSelection(  _screenWindow->selectedText(_preserveLineBreaks)  );
      }

      _actSel = 0;

      //FIXME: emits a release event even if the mouse is
      //       outside the range. The procedure used in `mouseMoveEvent'
      //       applies here, too.

      if (!_mouseMarks && !(ev->modifiers() & Qt::ShiftModifier))
        emit mouseSignal( 0,
                        charColumn + 1,
                        charLine + 1 +_scrollBar->value() -_scrollBar->maximum() , 2);
    }
    dragInfo.state = diNone;
  }


  if ( !_mouseMarks &&
       ((ev->button() == Qt::RightButton && !(ev->modifiers() & Qt::ShiftModifier))
                        || ev->button() == Qt::MidButton) )
  {
    emit mouseSignal( ev->button() == Qt::MidButton ? 1 : 2,
                      charColumn + 1,
                      charLine + 1 +_scrollBar->value() -_scrollBar->maximum() ,
                      2);
  }
}

void TerminalDisplay::getCharacterPosition(const QPoint& widgetPoint,int& line,int& column) const
{
    line = (widgetPoint.y()-contentsRect().top()-_topMargin) / _fontHeight;

    if ( _fixedFont )
        column = (widgetPoint.x() + _fontWidth/2 -contentsRect().left()-_leftMargin) / _fontWidth;
    else
    {
        int x = contentsRect().left() + widgetPoint.x() - _fontWidth/2;
        column = 0;

        while(x > textWidth(0, column, line))
            column++;
    }

    if ( line < 0 )
        line = 0;
    if ( column < 0 )
        column = 0;

    if ( line >= _usedLines )
        line = _usedLines-1;

    // the column value returned can be equal to _usedColumns, which
    // is the position just after the last character displayed in a line.
    //
    // this is required so that the user can select characters in the right-most
    // column (or left-most for right-to-left input)
    if ( column > _usedColumns )
        column = _usedColumns;
}

void TerminalDisplay::updateFilters()
{
    if ( !_screenWindow )
        return;

    processFilters();
}

void TerminalDisplay::updateLineProperties()
{
    if ( !_screenWindow )
        return;

    _lineProperties = _screenWindow->getLineProperties();
}

void TerminalDisplay::mouseDoubleClickEvent(QMouseEvent* ev)
{
  if ( ev->button() != Qt::LeftButton) return;
  if ( !_screenWindow ) return;

  int charLine = 0;
  int charColumn = 0;

  getCharacterPosition(ev->pos(),charLine,charColumn);

  QPoint pos(charColumn,charLine);

  // pass on double click as two clicks.
  if (!_mouseMarks && !(ev->modifiers() & Qt::ShiftModifier))
  {
    // Send just _ONE_ click event, since the first click of the double click
    // was already sent by the click handler
    emit mouseSignal( 0,
                      pos.x()+1,
                      pos.y()+1 +_scrollBar->value() -_scrollBar->maximum(),
                      0 ); // left button
    return;
  }

  _screenWindow->clearSelection();
  QPoint bgnSel = pos;
  QPoint endSel = pos;
  int i = loc(bgnSel.x(),bgnSel.y());
  _iPntSel = bgnSel;
  _iPntSel.ry() += _scrollBar->value();

  _wordSelectionMode = true;

  // find word boundaries...
  QChar selClass = charClass(_image[i].character);
  {
     // find the start of the word
     int x = bgnSel.x();
     while ( ((x>0) || (bgnSel.y()>0 && (_lineProperties[bgnSel.y()-1] & LINE_WRAPPED) ))
                     && charClass(_image[i-1].character) == selClass )
     {
       i--;
       if (x>0)
           x--;
       else
       {
           x=_usedColumns-1;
           bgnSel.ry()--;
       }
     }

     bgnSel.setX(x);
     _screenWindow->setSelectionStart( bgnSel.x() , bgnSel.y() , false );

     // find the end of the word
     i = loc( endSel.x(), endSel.y() );
     x = endSel.x();
     while( ((x<_usedColumns-1) || (endSel.y()<_usedLines-1 && (_lineProperties[endSel.y()] & LINE_WRAPPED) ))
                     && charClass(_image[i+1].character) == selClass )
     {
         i++;
         if (x<_usedColumns-1)
             x++;
         else
         {
             x=0;
             endSel.ry()++;
         }
     }

     endSel.setX(x);

     // In word selection mode don't select @ (64) if at end of word.
     if ( ( QChar( _image[i].character ) == '@' ) && ( ( endSel.x() - bgnSel.x() ) > 0 ) )
       endSel.setX( x - 1 );


     _actSel = 2; // within selection

     _screenWindow->setSelectionEnd( endSel.x() , endSel.y() );

     setSelection( _screenWindow->selectedText(_preserveLineBreaks) );
   }

  _possibleTripleClick=true;

  QTimer::singleShot(QApplication::doubleClickInterval(),this,
                     SLOT(tripleClickTimeout()));
}

void TerminalDisplay::wheelEvent( QWheelEvent* ev )
{
  if (ev->orientation() != Qt::Vertical)
    return;

  // if the terminal program is not interested mouse events
  // then send the event to the scrollbar if the slider has room to move
  // or otherwise send simulated up / down key presses to the terminal program
  // for the benefit of programs such as 'less'
  if ( _mouseMarks )
  {
    bool canScroll = _scrollBar->maximum() > 0;
      if (canScroll)
        _scrollBar->event(ev);
    else
    {
        // assume that each Up / Down key event will cause the terminal application
        // to scroll by one line.
        //
        // to get a reasonable scrolling speed, scroll by one line for every 5 degrees
        // of mouse wheel rotation.  Mouse wheels typically move in steps of 15 degrees,
        // giving a scroll of 3 lines
        int key = ev->delta() > 0 ? Qt::Key_Up : Qt::Key_Down;

        // QWheelEvent::delta() gives rotation in eighths of a degree
        int wheelDegrees = ev->delta() / 8;
        int linesToScroll = abs(wheelDegrees) / 5;

        QKeyEvent keyScrollEvent(QEvent::KeyPress,key,Qt::NoModifier);

        for (int i=0;i<linesToScroll;i++)
            emit keyPressedSignal(&keyScrollEvent);
    }
  }
  else
  {
    // terminal program wants notification of mouse activity

    int charLine;
    int charColumn;
    getCharacterPosition( ev->pos() , charLine , charColumn );

    emit mouseSignal( ev->delta() > 0 ? 4 : 5,
                      charColumn + 1,
                      charLine + 1 +_scrollBar->value() -_scrollBar->maximum() ,
                      0);
  }
}

void TerminalDisplay::tripleClickTimeout()
{
  _possibleTripleClick=false;
}

void TerminalDisplay::mouseTripleClickEvent(QMouseEvent* ev)
{
  if ( !_screenWindow ) return;

  int charLine;
  int charColumn;
  getCharacterPosition(ev->pos(),charLine,charColumn);
  _iPntSel = QPoint(charColumn,charLine);

  _screenWindow->clearSelection();

  _lineSelectionMode = true;
  _wordSelectionMode = false;

  _actSel = 2; // within selection
  emit isBusySelecting(true); // Keep it steady...

  while (_iPntSel.y()>0 && (_lineProperties[_iPntSel.y()-1] & LINE_WRAPPED) )
    _iPntSel.ry()--;

  if (_tripleClickMode == SelectForwardsFromCursor) {
    // find word boundary start
    int i = loc(_iPntSel.x(),_iPntSel.y());
    QChar selClass = charClass(_image[i].character);
    int x = _iPntSel.x();

    while ( ((x>0) ||
             (_iPntSel.y()>0 && (_lineProperties[_iPntSel.y()-1] & LINE_WRAPPED) )
            )
            && charClass(_image[i-1].character) == selClass )
    {
        i--;
        if (x>0)
            x--;
        else
        {
            x=_columns-1;
            _iPntSel.ry()--;
        }
    }

    _screenWindow->setSelectionStart( x , _iPntSel.y() , false );
    _tripleSelBegin = QPoint( x, _iPntSel.y() );
  }
  else if (_tripleClickMode == SelectWholeLine) {
    _screenWindow->setSelectionStart( 0 , _iPntSel.y() , false );
    _tripleSelBegin = QPoint( 0, _iPntSel.y() );
  }

  while (_iPntSel.y()<_lines-1 && (_lineProperties[_iPntSel.y()] & LINE_WRAPPED) )
    _iPntSel.ry()++;

  _screenWindow->setSelectionEnd( _columns - 1 , _iPntSel.y() );

  setSelection(_screenWindow->selectedText(_preserveLineBreaks));

  _iPntSel.ry() += _scrollBar->value();
}


bool TerminalDisplay::focusNextPrevChild( bool next )
{
  if (next)
    return false; // This disables changing the active part in konqueror
                  // when pressing Tab
  return QWidget::focusNextPrevChild( next );
}


QChar TerminalDisplay::charClass(QChar qch) const
{
    if ( qch.isSpace() ) return ' ';

    if ( qch.isLetterOrNumber() || _wordCharacters.contains(qch, Qt::CaseInsensitive ) )
    return 'a';

    return qch;
}

void TerminalDisplay::setWordCharacters(const QString& wc)
{
    _wordCharacters = wc;
}

void TerminalDisplay::setUsesMouse(bool on)
{
    if (_mouseMarks != on) {
        _mouseMarks = on;
        setCursor( _mouseMarks ? Qt::IBeamCursor : Qt::ArrowCursor );
        emit usesMouseChanged();
    }
}
bool TerminalDisplay::usesMouse() const
{
    return _mouseMarks;
}

void TerminalDisplay::setBracketedPasteMode(bool on)
{
    _bracketedPasteMode = on;
}
bool TerminalDisplay::bracketedPasteMode() const
{
    return _bracketedPasteMode;
}

/* ------------------------------------------------------------------------- */
/*                                                                           */
/*                               Clipboard                                   */
/*                                                                           */
/* ------------------------------------------------------------------------- */

#undef KeyPress

void TerminalDisplay::emitSelection(bool useXselection,bool appendReturn)
{
  if ( !_screenWindow )
      return;

  // Paste Clipboard by simulating keypress events
  QString text = QApplication::clipboard()->text(useXselection ? QClipboard::Selection :
                                                                 QClipboard::Clipboard);
  if(appendReturn)
    text.append("\r");
  if ( ! text.isEmpty() )
  {
    text.replace('\n', '\r');
    bracketText(text);
    QKeyEvent e(QEvent::KeyPress, 0, Qt::NoModifier, text);
    emit keyPressedSignal(&e); // expose as a big fat keypress event

    _screenWindow->clearSelection();
  }
}

void TerminalDisplay::bracketText(QString& text)
{
    if (bracketedPasteMode())
    {
        text.prepend("\033[200~");
        text.append("\033[201~");
    }
}

void TerminalDisplay::setSelection(const QString& t)
{
  QApplication::clipboard()->setText(t, QClipboard::Selection);
}

void TerminalDisplay::copyClipboard()
{
  if ( !_screenWindow )
      return;

  QString text = _screenWindow->selectedText(_preserveLineBreaks);
  if (!text.isEmpty())
    QApplication::clipboard()->setText(text);
}

void TerminalDisplay::pasteClipboard()
{
  emitSelection(false,false);
}

void TerminalDisplay::pasteSelection()
{
  emitSelection(true,false);
}

/* ------------------------------------------------------------------------- */
/*                                                                           */
/*                                Keyboard                                   */
/*                                                                           */
/* ------------------------------------------------------------------------- */

void TerminalDisplay::setFlowControlWarningEnabled( bool enable )
{
    _flowControlWarningEnabled = enable;

    // if the dialog is currently visible and the flow control warning has
    // been disabled then hide the dialog
    if (!enable)
        outputSuspended(false);
}

void TerminalDisplay::setMotionAfterPasting(MotionAfterPasting action)
{
    mMotionAfterPasting = action;
}

int TerminalDisplay::motionAfterPasting()
{
    return mMotionAfterPasting;
}

void TerminalDisplay::keyPressEvent( QKeyEvent* event )
{
    bool emitKeyPressSignal = true;

    // Keyboard-based navigation
    if ( event->modifiers() == Qt::ShiftModifier )
    {
        bool update = true;

        if ( event->key() == Qt::Key_PageUp )
        {
            _screenWindow->scrollBy( ScreenWindow::ScrollPages , -1 );
        }
        else if ( event->key() == Qt::Key_PageDown )
        {
            _screenWindow->scrollBy( ScreenWindow::ScrollPages , 1 );
        }
        else if ( event->key() == Qt::Key_Up )
        {
            _screenWindow->scrollBy( ScreenWindow::ScrollLines , -1 );
        }
        else if ( event->key() == Qt::Key_Down )
        {
            _screenWindow->scrollBy( ScreenWindow::ScrollLines , 1 );
        }
        else if ( event->key() == Qt::Key_End)
        {
            scrollToEnd();
        }
        else if ( event->key() == Qt::Key_Home)
        {
            _screenWindow->scrollTo(0);
        }
        else
            update = false;

        if ( update )
        {
            _screenWindow->setTrackOutput( _screenWindow->atEndOfOutput() );

            updateLineProperties();
            updateImage();

            // do not send key press to terminal
            emitKeyPressSignal = false;
        }
    }

    _actSel=0; // Key stroke implies a screen update, so TerminalDisplay won't
              // know where the current selection is.

    if (_hasBlinkingCursor)
    {
      _blinkCursorTimer->start(QApplication::cursorFlashTime() / 2);
      if (_cursorBlinking)
        blinkCursorEvent();
      else
        _cursorBlinking = false;
    }

    if ( emitKeyPressSignal )
    {
        emit keyPressedSignal(event);

        if(event->modifiers().testFlag(Qt::ShiftModifier)
             || event->modifiers().testFlag(Qt::ControlModifier)
             || event->modifiers().testFlag(Qt::AltModifier))
        {
            switch(mMotionAfterPasting)
            {
            case MoveStartScreenWindow:
                _screenWindow->scrollTo(0);
                break;
            case MoveEndScreenWindow:
                scrollToEnd();
                break;
            case NoMoveScreenWindow:
                break;
            }
        }
        else
        {
            scrollToEnd();
        }
    }

    event->accept();
}

void TerminalDisplay::inputMethodEvent( QInputMethodEvent* event )
{
    QKeyEvent keyEvent(QEvent::KeyPress,0,Qt::NoModifier,event->commitString());
    emit keyPressedSignal(&keyEvent);

    _inputMethodData.preeditString = event->preeditString().toStdWString();
    update(preeditRect() | _inputMethodData.previousPreeditRect);

    event->accept();
}
QVariant TerminalDisplay::inputMethodQuery( Qt::InputMethodQuery query ) const
{
    const QPoint cursorPos = _screenWindow ? _screenWindow->cursorPosition() : QPoint(0,0);
    switch ( query )
    {
        case Qt::ImMicroFocus:
                return imageToWidget(QRect(cursorPos.x(),cursorPos.y(),1,1));
            break;
        case Qt::ImFont:
                return font();
            break;
        case Qt::ImCursorPosition:
                // return the cursor position within the current line
                return cursorPos.x();
            break;
        case Qt::ImSurroundingText:
            {
                // return the text from the current line
                QString lineText;
                QTextStream stream(&lineText);
                PlainTextDecoder decoder;
                decoder.begin(&stream);
                decoder.decodeLine(&_image[loc(0,cursorPos.y())],_usedColumns,_lineProperties[cursorPos.y()]);
                decoder.end();
                return lineText;
            }
            break;
        case Qt::ImCurrentSelection:
                return QString();
            break;
        default:
            break;
    }

    return QVariant();
}

bool TerminalDisplay::handleShortcutOverrideEvent(QKeyEvent* keyEvent)
{
    int modifiers = keyEvent->modifiers();

    //  When a possible shortcut combination is pressed,
    //  emit the overrideShortcutCheck() signal to allow the host
    //  to decide whether the terminal should override it or not.
    if (modifiers != Qt::NoModifier)
    {
        int modifierCount = 0;
        unsigned int currentModifier = Qt::ShiftModifier;

        while (currentModifier <= Qt::KeypadModifier)
        {
            if (modifiers & currentModifier)
                modifierCount++;
            currentModifier <<= 1;
        }
        if (modifierCount < 2)
        {
            bool override = false;
            emit overrideShortcutCheck(keyEvent,override);
            if (override)
            {
                keyEvent->accept();
                return true;
            }
        }
    }

    // Override any of the following shortcuts because
    // they are needed by the terminal
    int keyCode = keyEvent->key() | modifiers;
    switch ( keyCode )
    {
      // list is taken from the QLineEdit::event() code
      case Qt::Key_Tab:
      case Qt::Key_Delete:
      case Qt::Key_Home:
      case Qt::Key_End:
      case Qt::Key_Backspace:
      case Qt::Key_Left:
      case Qt::Key_Right:
      case Qt::Key_Escape:
        keyEvent->accept();
        return true;
    }
    return false;
}

bool TerminalDisplay::event(QEvent* event)
{
  bool eventHandled = false;
  switch (event->type())
  {
    case QEvent::ShortcutOverride:
        eventHandled = handleShortcutOverrideEvent((QKeyEvent*)event);
        break;
    case QEvent::PaletteChange:
    case QEvent::ApplicationPaletteChange:
        _scrollBar->setPalette( QApplication::palette() );
        break;
    default:
        break;
  }
  return eventHandled ? true : QWidget::event(event);
}

void TerminalDisplay::setBellMode(int mode)
{
  _bellMode=mode;
}

void TerminalDisplay::enableBell()
{
    _allowBell = true;
}

void TerminalDisplay::bell(const QString& message)
{
  if (_bellMode==NoBell) return;

  //limit the rate at which bells can occur
  //...mainly for sound effects where rapid bells in sequence
  //produce a horrible noise
  if ( _allowBell )
  {
    _allowBell = false;
    QTimer::singleShot(500,this,SLOT(enableBell()));

    if (_bellMode==SystemBeepBell)
    {
        QApplication::beep();
    }
    else if (_bellMode==NotifyBell)
    {
        emit notifyBell(message);
    }
    else if (_bellMode==VisualBell)
    {
        swapColorTable();
        QTimer::singleShot(200,this,SLOT(swapColorTable()));
    }
  }
}

void TerminalDisplay::selectionChanged()
{
    emit copyAvailable(_screenWindow->selectedText(false).isEmpty() == false);
}

void TerminalDisplay::swapColorTable()
{
  ColorEntry color = _colorTable[1];
  _colorTable[1]=_colorTable[0];
  _colorTable[0]= color;
  _colorsInverted = !_colorsInverted;
  update();
}

void TerminalDisplay::clearImage()
{
  // We initialize _image[_imageSize] too. See makeImage()
  for (int i = 0; i <= _imageSize; i++)
  {
    _image[i].character = ' ';
    _image[i].foregroundColor = CharacterColor(COLOR_SPACE_DEFAULT,
                                               DEFAULT_FORE_COLOR);
    _image[i].backgroundColor = CharacterColor(COLOR_SPACE_DEFAULT,
                                               DEFAULT_BACK_COLOR);
    _image[i].rendition = DEFAULT_RENDITION;
  }
}

void TerminalDisplay::calcGeometry()
{
  _scrollBar->resize(_scrollBar->sizeHint().width(), contentsRect().height());
  int scrollBarWidth = _scrollBar->style()->styleHint(QStyle::SH_ScrollBar_Transient, nullptr, _scrollBar)
                       ? 0 : _scrollBar->width();
  switch(_scrollbarLocation)
  {
    case QTermWidget::NoScrollBar :
     _leftMargin = DEFAULT_LEFT_MARGIN;
     _contentWidth = contentsRect().width() - 2 * DEFAULT_LEFT_MARGIN;
     break;
    case QTermWidget::ScrollBarLeft :
     _leftMargin = DEFAULT_LEFT_MARGIN + scrollBarWidth;
     _contentWidth = contentsRect().width() - 2 * DEFAULT_LEFT_MARGIN - scrollBarWidth;
     _scrollBar->move(contentsRect().topLeft());
     break;
    case QTermWidget::ScrollBarRight:
     _leftMargin = DEFAULT_LEFT_MARGIN;
     _contentWidth = contentsRect().width()  - 2 * DEFAULT_LEFT_MARGIN - scrollBarWidth;
     _scrollBar->move(contentsRect().topRight() - QPoint(_scrollBar->width()-1, 0));
     break;
  }

  _topMargin = DEFAULT_TOP_MARGIN;
  _contentHeight = contentsRect().height() - 2 * DEFAULT_TOP_MARGIN + /* mysterious */ 1;

  if (!_isFixedSize)
  {
     // ensure that display is always at least one column wide
     _columns = qMax(1,_contentWidth / _fontWidth);
     _usedColumns = qMin(_usedColumns,_columns);

     // ensure that display is always at least one line high
     _lines = qMax(1,_contentHeight / _fontHeight);
     _usedLines = qMin(_usedLines,_lines);
  }
}

void TerminalDisplay::makeImage()
{
  calcGeometry();

  // confirm that array will be of non-zero size, since the painting code
  // assumes a non-zero array length
  Q_ASSERT( _lines > 0 && _columns > 0 );
  Q_ASSERT( _usedLines <= _lines && _usedColumns <= _columns );

  _imageSize=_lines*_columns;

  // We over-commit one character so that we can be more relaxed in dealing with
  // certain boundary conditions: _image[_imageSize] is a valid but unused position
  _image = new Character[_imageSize+1];

  clearImage();
}

// calculate the needed size, this must be synced with calcGeometry()
void TerminalDisplay::setSize(int columns, int lines)
{
  int scrollBarWidth = (_scrollBar->isHidden()
                        || _scrollBar->style()->styleHint(QStyle::SH_ScrollBar_Transient, nullptr, _scrollBar))
                       ? 0 : _scrollBar->sizeHint().width();
  int horizontalMargin = 2 * DEFAULT_LEFT_MARGIN;
  int verticalMargin = 2 * DEFAULT_TOP_MARGIN;

  QSize newSize = QSize( horizontalMargin + scrollBarWidth + (columns * _fontWidth)  ,
                 verticalMargin + (lines * _fontHeight)   );

  if ( newSize != size() )
  {
    _size = newSize;
    updateGeometry();
  }
}

void TerminalDisplay::setFixedSize(int cols, int lins)
{
  _isFixedSize = true;

  //ensure that display is at least one line by one column in size
  _columns = qMax(1,cols);
  _lines = qMax(1,lins);
  _usedColumns = qMin(_usedColumns,_columns);
  _usedLines = qMin(_usedLines,_lines);

  if (_image)
  {
     delete[] _image;
     makeImage();
  }
  setSize(cols, lins);
  QWidget::setFixedSize(_size);
}

QSize TerminalDisplay::sizeHint() const
{
  return _size;
}


/* --------------------------------------------------------------------- */
/*                                                                       */
/* Drag & Drop                                                           */
/*                                                                       */
/* --------------------------------------------------------------------- */

void TerminalDisplay::dragEnterEvent(QDragEnterEvent* event)
{
  if (event->mimeData()->hasFormat("text/plain"))
      event->acceptProposedAction();
  if (event->mimeData()->urls().count())
      event->acceptProposedAction();
}

void TerminalDisplay::dropEvent(QDropEvent* event)
{
  //KUrl::List urls = KUrl::List::fromMimeData(event->mimeData());
  QList<QUrl> urls = event->mimeData()->urls();

  QString dropText;
  if (!urls.isEmpty())
  {
      // TODO/FIXME: escape or quote pasted things if neccessary...
      qDebug() << "TerminalDisplay: handling urls. It can be broken. Report any errors, please";
    for ( int i = 0 ; i < urls.count() ; i++ )
    {
        //KUrl url = KIO::NetAccess::mostLocalUrl( urls[i] , 0 );
        QUrl url = urls[i];

        QString urlText;

        if (url.isLocalFile())
            urlText = url.path();
        else
            urlText = url.toString();

        // in future it may be useful to be able to insert file names with drag-and-drop
        // without quoting them (this only affects paths with spaces in)
        //urlText = KShell::quoteArg(urlText);

        dropText += urlText;

        if ( i != urls.count()-1 )
            dropText += ' ';
    }
  }
  else
  {
    dropText = event->mimeData()->text();
  }

    emit sendStringToEmu(dropText.toLocal8Bit());
}

void TerminalDisplay::doDrag()
{
  dragInfo.state = diDragging;
  dragInfo.dragObject = new QDrag(this);
  QMimeData *mimeData = new QMimeData;
  mimeData->setText(QApplication::clipboard()->text(QClipboard::Selection));
  dragInfo.dragObject->setMimeData(mimeData);
  dragInfo.dragObject->start(Qt::CopyAction);
  // Don't delete the QTextDrag object.  Qt will delete it when it's done with it.
}

void TerminalDisplay::outputSuspended(bool suspended)
{
    //create the label when this function is first called
    if (!_outputSuspendedLabel)
    {
            //This label includes a link to an English language website
            //describing the 'flow control' (Xon/Xoff) feature found in almost
            //all terminal emulators.
            //If there isn't a suitable article available in the target language the link
            //can simply be removed.
            _outputSuspendedLabel = new QLabel( tr("<qt>Output has been "
                                                "<a href=\"http://en.wikipedia.org/wiki/Flow_control\">suspended</a>"
                                                " by pressing Ctrl+S."
                                               "  Press <b>Ctrl+Q</b> to resume.</qt>"),
                                               this );

            QPalette palette(_outputSuspendedLabel->palette());
            //KColorScheme::adjustBackground(palette,KColorScheme::NeutralBackground);
            _outputSuspendedLabel->setPalette(palette);
            _outputSuspendedLabel->setAutoFillBackground(true);
            _outputSuspendedLabel->setBackgroundRole(QPalette::Base);
            _outputSuspendedLabel->setFont(QApplication::font());
            _outputSuspendedLabel->setContentsMargins(5, 5, 5, 5);

            //enable activation of "Xon/Xoff" link in label
            _outputSuspendedLabel->setTextInteractionFlags(Qt::LinksAccessibleByMouse |
                                                          Qt::LinksAccessibleByKeyboard);
            _outputSuspendedLabel->setOpenExternalLinks(true);
            _outputSuspendedLabel->setVisible(false);

            _gridLayout->addWidget(_outputSuspendedLabel);
            _gridLayout->addItem( new QSpacerItem(0,0,QSizePolicy::Expanding,
                                                      QSizePolicy::Expanding),
                                 1,0);

    }

    _outputSuspendedLabel->setVisible(suspended);
}

uint TerminalDisplay::lineSpacing() const
{
  return _lineSpacing;
}

void TerminalDisplay::setLineSpacing(uint i)
{
  _lineSpacing = i;
  setVTFont(font()); // Trigger an update.
}

AutoScrollHandler::AutoScrollHandler(QWidget* parent)
: QObject(parent)
, _timerId(0)
{
    parent->installEventFilter(this);
}
void AutoScrollHandler::timerEvent(QTimerEvent* event)
{
    if (event->timerId() != _timerId)
        return;

    QMouseEvent mouseEvent(    QEvent::MouseMove,
                              widget()->mapFromGlobal(QCursor::pos()),
                              Qt::NoButton,
                              Qt::LeftButton,
                              Qt::NoModifier);

    QApplication::sendEvent(widget(),&mouseEvent);
}
bool AutoScrollHandler::eventFilter(QObject* watched,QEvent* event)
{
    Q_ASSERT( watched == parent() );
    Q_UNUSED( watched );

    QMouseEvent* mouseEvent = (QMouseEvent*)event;
    switch (event->type())
    {
        case QEvent::MouseMove:
        {
            bool mouseInWidget = widget()->rect().contains(mouseEvent->pos());

            if (mouseInWidget)
            {
                if (_timerId)
                    killTimer(_timerId);
                _timerId = 0;
            }
            else
            {
                if (!_timerId && (mouseEvent->buttons() & Qt::LeftButton))
                    _timerId = startTimer(100);
            }
                break;
        }
        case QEvent::MouseButtonRelease:
            if (_timerId && (mouseEvent->buttons() & ~Qt::LeftButton))
            {
                killTimer(_timerId);
                _timerId = 0;
            }
        break;
        default:
        break;
    };

    return false;
}

//#include "TerminalDisplay.moc"