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svgalibpaintengine.cpp Example File
qws/svgalib/svgalibpaintengine.cpp

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 #include "svgalibpaintengine.h"

 #include <QColor>
 #include <vga.h>
 #include <vgagl.h>

 SvgalibPaintEngine::SvgalibPaintEngine()
 {
 }

 SvgalibPaintEngine::~SvgalibPaintEngine()
 {
 }

 bool SvgalibPaintEngine::begin(QPaintDevice *dev)
 {
     device = dev;
     pen = Qt::NoPen;
     simplePen = true;
     brush = Qt::NoBrush;
     simpleBrush = true;
     matrix = QMatrix();
     simpleMatrix = true;
     setClip(QRect(0, 0, device->width(), device->height()));
     opaque = true;
     aliased = true;
     sourceOver = true;

     return QRasterPaintEngine::begin(dev);
 }

 bool SvgalibPaintEngine::end()
 {
     gl_setclippingwindow(0, 0, device->width() - 1, device->height() - 1);
     return QRasterPaintEngine::end();
 }

 void SvgalibPaintEngine::updateState(const QPaintEngineState &state)
 {
     QPaintEngine::DirtyFlags flags = state.state();

     if (flags & DirtyTransform) {
         matrix = state.matrix();
         simpleMatrix = (matrix.m12() == 0 && matrix.m21() == 0);
     }

     if (flags & DirtyPen) {
         pen = state.pen();
         simplePen = (pen.width() == 0 || pen.widthF() <= 1)
                     && (pen.style() == Qt::NoPen || pen.style() == Qt::SolidLine)
                     && (pen.color().alpha() == 255);
     }

     if (flags & DirtyBrush) {
         brush = state.brush();
         simpleBrush = (brush.style() == Qt::SolidPattern
                        || brush.style() == Qt::NoBrush)
                       && (brush.color().alpha() == 255);
     }

     if (flags & DirtyClipRegion)
         setClip(state.clipRegion());

     if (flags & DirtyClipEnabled) {
         clipEnabled = state.isClipEnabled();
         updateClip();
     }

     if (flags & DirtyClipPath) {
         setClip(QRegion());
         simpleClip = false;
     }

     if (flags & DirtyCompositionMode) {
         const QPainter::CompositionMode m = state.compositionMode();
         sourceOver = (m == QPainter::CompositionMode_SourceOver);
     }

     if (flags & DirtyOpacity)
         opaque = (state.opacity() == 256);

     if (flags & DirtyHints)
         aliased = !(state.renderHints() & QPainter::Antialiasing);

     QRasterPaintEngine::updateState(state);
 }

 void SvgalibPaintEngine::setClip(const QRegion &region)
 {
     if (region.isEmpty())
         clip = QRect(0, 0, device->width(), device->height());
     else
         clip = matrix.map(region) & QRect(0, 0, device->width(), device->height());
     clipEnabled = true;
     updateClip();
 }

 void SvgalibPaintEngine::updateClip()
 {
     QRegion clipRegion = QRect(0, 0, device->width(), device->height());

     if (!systemClip().isEmpty())
         clipRegion &= systemClip();
     if (clipEnabled)
         clipRegion &= clip;

     simpleClip = (clipRegion.rects().size() <= 1);

     const QRect r = clipRegion.boundingRect();
     gl_setclippingwindow(r.left(), r.top(),
                          r.x() + r.width(),
                          r.y() + r.height());
 }

 void SvgalibPaintEngine::drawRects(const QRect *rects, int rectCount)
 {
     const bool canAccelerate = simplePen && simpleBrush && simpleMatrix
                                && simpleClip && opaque && aliased
                                && sourceOver;
     if (!canAccelerate) {
         QRasterPaintEngine::drawRects(rects, rectCount);
         return;
     }

     for (int i = 0; i < rectCount; ++i) {
         const QRect r = matrix.mapRect(rects[i]);
         if (brush != Qt::NoBrush) {
             gl_fillbox(r.left(), r.top(), r.width(), r.height(),
                        brush.color().rgba());
         }
         if (pen != Qt::NoPen) {
             const int c = pen.color().rgba();
             gl_hline(r.left(), r.top(), r.right(), c);
             gl_hline(r.left(), r.bottom(), r.right(), c);
             gl_line(r.left(), r.top(), r.left(), r.bottom(), c);
             gl_line(r.right(), r.top(), r.right(), r.bottom(), c);
         }
     }
 }