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direct2d: Optimize dashed line drawing

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This introduces a combined brush/dash pattern which can be used to
perform faster dashed straight-line drawing. The dash pattern is
prerendered to a tiled bitmap brush, resulting in a significant speedup
for lines with many elements.

As the result of non-rectilinear lines may lose quality compared to the
native dashed renderer, the slow/high quality codepath can be activated
by setting the QPainter::HighQualityAntialiasing render hint.

Task-number: QTBUG-40604
Change-Id: I771e9a81c042b4d8b6891dc9280932696e5a0694
Reviewed-by: Andrew Knight <andrew.knight@digia.com>
Reviewed-by: Louai Al-Khanji <louai.al-khanji@digia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
This commit is contained in:
Andrew Knight 2014-09-19 14:23:56 +03:00 committed by Louai Al-Khanji
parent 3bcbff57e1
commit a1dea3a62c
1 changed files with 45 additions and 3 deletions
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44
src/plugins/platforms/direct2d/qwindowsdirect2dpaintengine.cpp
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@ -43,6 +43,7 @@
#include "qwindowsfontdatabase.h"
#include "qwindowsintegration.h"
#include <QtCore/QtMath>
#include <QtCore/QStack>
#include <QtCore/QSettings>
#include <QtGui/private/qpaintengine_p.h>
@ -101,6 +102,16 @@ static inline ID2D1Factory1 *factory()
return QWindowsDirect2DContext::instance()->d2dFactory();
}
static inline D2D1_MATRIX_3X2_F transformFromLine(const QLineF &line, qreal penWidth)
{
const qreal halfWidth = penWidth / 2;
const qreal angle = -qDegreesToRadians(line.angle());
QTransform transform = QTransform::fromTranslate(line.p1().x() + qSin(angle) * halfWidth,
line.p1().y() - qCos(angle) * halfWidth);
transform.rotateRadians(angle);
return to_d2d_matrix_3x2_f(transform);
}
class Direct2DPathGeometryWriter
{
public:
@ -245,12 +256,14 @@ public:
QPen qpen;
ComPtr<ID2D1Brush> brush;
ComPtr<ID2D1StrokeStyle1> strokeStyle;
ComPtr<ID2D1BitmapBrush1> dashBrush;
inline void reset() {
emulate = false;
qpen = QPen();
brush.Reset();
strokeStyle.Reset();
dashBrush.Reset();
}
} pen;
@ -528,12 +541,31 @@ public:
if (props.dashStyle == D2D1_DASH_STYLE_CUSTOM) {
QVector<qreal> dashes = newPen.dashPattern();
QVector<FLOAT> converted(dashes.size());
qreal penWidth = pen.qpen.widthF();
qreal brushWidth = 0;
for (int i = 0; i < dashes.size(); i++) {
converted[i] = dashes[i];
brushWidth += penWidth * dashes[i];
}
hr = factory()->CreateStrokeStyle(props, converted.constData(), converted.size(), &pen.strokeStyle);
// Create a combined brush/dash pattern for optimized line drawing
QWindowsDirect2DBitmap bitmap;
bitmap.resize(ceil(brushWidth), ceil(penWidth));
bitmap.deviceContext()->begin();
bitmap.deviceContext()->get()->SetAntialiasMode(antialiasMode());
bitmap.deviceContext()->get()->SetTransform(D2D1::IdentityMatrix());
bitmap.deviceContext()->get()->Clear();
const qreal offsetX = (qreal(bitmap.size().width()) - brushWidth) / 2;
const qreal offsetY = qreal(bitmap.size().height()) / 2;
bitmap.deviceContext()->get()->DrawLine(D2D1::Point2F(offsetX, offsetY),
D2D1::Point2F(brushWidth, offsetY),
pen.brush.Get(), penWidth, pen.strokeStyle.Get());
bitmap.deviceContext()->end();
D2D1_BITMAP_BRUSH_PROPERTIES1 bitmapBrushProperties = D2D1::BitmapBrushProperties1(
D2D1_EXTEND_MODE_WRAP, D2D1_EXTEND_MODE_CLAMP, D2D1_INTERPOLATION_MODE_LINEAR);
hr = dc()->CreateBitmapBrush(bitmap.bitmap(), bitmapBrushProperties, &pen.dashBrush);
} else {
hr = factory()->CreateStrokeStyle(props, NULL, 0, &pen.strokeStyle);
}
@ -1296,7 +1328,12 @@ void QWindowsDirect2DPaintEngine::drawLines(const QLine *lines, int lineCount)
D2D1_POINT_2F d2d_p1 = to_d2d_point_2f(p1);
D2D1_POINT_2F d2d_p2 = to_d2d_point_2f(p2);
if (!d->pen.dashBrush || state()->renderHints.testFlag(QPainter::HighQualityAntialiasing)) {
d->dc()->DrawLine(d2d_p1, d2d_p2, d->pen.brush.Get(), d->pen.qpen.widthF(), d->pen.strokeStyle.Get());
} else {
d->pen.dashBrush->SetTransform(transformFromLine(lines[i], d->pen.qpen.widthF()));
d->dc()->DrawLine(d2d_p1, d2d_p2, d->pen.dashBrush.Get(), d->pen.qpen.widthF(), NULL);
}
}
}
}
@ -1332,7 +1369,12 @@ void QWindowsDirect2DPaintEngine::drawLines(const QLineF *lines, int lineCount)
D2D1_POINT_2F d2d_p1 = to_d2d_point_2f(p1);
D2D1_POINT_2F d2d_p2 = to_d2d_point_2f(p2);
if (!d->pen.dashBrush || state()->renderHints.testFlag(QPainter::HighQualityAntialiasing)) {
d->dc()->DrawLine(d2d_p1, d2d_p2, d->pen.brush.Get(), d->pen.qpen.widthF(), d->pen.strokeStyle.Get());
} else {
d->pen.dashBrush->SetTransform(transformFromLine(lines[i], d->pen.qpen.widthF()));
d->dc()->DrawLine(d2d_p1, d2d_p2, d->pen.dashBrush.Get(), d->pen.qpen.widthF(), NULL);
}
}
}
}