Do not always fallback to bitmap printing when printing alpha.

The previous code resulted in that all regions that had some alpha
blending content had to be rasterized as bitmaps.

With this patch, we only need to fallback to proper alpha blending
if there is a background content to blend against.
If there is no background content we simly assume that the background
is white (which happen to be the most common paper color). It will
then be treated as a solid background.

Task-number: QTBUG-33548
Change-Id: I9d2c9be95a701704cdb3724480421db49b4cdd98
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>
This commit is contained in:
Jan Arve Saether 2014-05-21 11:10:50 +02:00 committed by The Qt Project
parent 9ce8a6b94c
commit 739ad76846
3 changed files with 37 additions and 19 deletions

View File

@ -1,6 +1,6 @@
/****************************************************************************
**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the QtGui module of the Qt Toolkit.
@ -166,11 +166,14 @@ void QAlphaPaintEngine::drawPath(const QPainterPath &path)
if (d->m_pass == 0) {
d->m_continueCall = false;
if (d->m_hasalpha || d->m_advancedPen || d->m_advancedBrush
if (d->canSeeTroughBackground(d->m_hasalpha, tr) || d->m_advancedPen || d->m_advancedBrush
|| d->m_emulateProjectiveTransforms)
{
d->addAlphaRect(tr);
}
d->addDirtyRect(tr);
if (d->m_picengine)
d->m_picengine->drawPath(path);
} else {
@ -192,12 +195,14 @@ void QAlphaPaintEngine::drawPolygon(const QPointF *points, int pointCount, Polyg
if (d->m_pass == 0) {
d->m_continueCall = false;
if (d->m_hasalpha || d->m_advancedPen || d->m_advancedBrush
if (d->canSeeTroughBackground(d->m_hasalpha, tr) || d->m_advancedPen || d->m_advancedBrush
|| d->m_emulateProjectiveTransforms)
{
d->addAlphaRect(tr);
}
d->addDirtyRect(tr);
if (d->m_picengine)
d->m_picengine->drawPolygon(points, pointCount, mode);
} else {
@ -212,10 +217,12 @@ void QAlphaPaintEngine::drawPixmap(const QRectF &r, const QPixmap &pm, const QRe
QRectF tr = d->m_transform.mapRect(r);
if (d->m_pass == 0) {
d->m_continueCall = false;
if (pm.hasAlpha() || d->m_alphaOpacity || d->m_complexTransform || pm.isQBitmap()) {
if (d->canSeeTroughBackground(pm.hasAlpha() || d->m_alphaOpacity, tr) || d->m_complexTransform || pm.isQBitmap()) {
d->addAlphaRect(tr);
}
d->addDirtyRect(tr);
if (d->m_picengine)
d->m_picengine->drawPixmap(r, pm, sr);
@ -233,9 +240,12 @@ void QAlphaPaintEngine::drawTextItem(const QPointF &p, const QTextItem &textItem
if (d->m_pass == 0) {
d->m_continueCall = false;
if (d->m_alphaPen || d->m_alphaOpacity || d->m_advancedPen) {
if (d->canSeeTroughBackground(d->m_alphaPen || d->m_alphaOpacity, tr) || d->m_advancedPen) {
d->addAlphaRect(tr);
}
d->addDirtyRect(tr);
if (d->m_picengine) {
d->m_picengine->drawTextItem(p, textItem);
}
@ -252,9 +262,12 @@ void QAlphaPaintEngine::drawTiledPixmap(const QRectF &r, const QPixmap &pixmap,
if (d->m_pass == 0) {
d->m_continueCall = false;
if (pixmap.hasAlpha() || d->m_alphaOpacity || d->m_complexTransform || pixmap.isQBitmap()) {
if (d->canSeeTroughBackground(pixmap.hasAlpha() || d->m_alphaOpacity, brect) || d->m_complexTransform || pixmap.isQBitmap()) {
d->addAlphaRect(brect);
}
d->addDirtyRect(brect);
if (d->m_picengine)
d->m_picengine->drawTiledPixmap(r, pixmap, s);
} else {
@ -410,19 +423,14 @@ QRectF QAlphaPaintEnginePrivate::addPenWidth(const QPainterPath &path)
return (tmp.controlPointRect() * m_transform).boundingRect();
}
QRect QAlphaPaintEnginePrivate::toRect(const QRectF &rect) const
{
QRect r;
r.setLeft(int(rect.left()));
r.setTop(int(rect.top()));
r.setRight(int(rect.right() + 1));
r.setBottom(int(rect.bottom() + 1));
return r;
}
void QAlphaPaintEnginePrivate::addAlphaRect(const QRectF &rect)
{
m_alphargn |= toRect(rect);
m_alphargn |= rect.toAlignedRect();
}
bool QAlphaPaintEnginePrivate::canSeeTroughBackground(bool somethingInRectHasAlpha, const QRectF &rect) const
{
return somethingInRectHasAlpha && m_dirtyrgn.intersects(rect.toAlignedRect());
}
void QAlphaPaintEnginePrivate::drawAlphaImage(const QRectF &rect)
@ -474,7 +482,7 @@ void QAlphaPaintEnginePrivate::drawAlphaImage(const QRectF &rect)
bool QAlphaPaintEnginePrivate::fullyContained(const QRectF &rect) const
{
QRegion r(toRect(rect));
QRegion r(rect.toAlignedRect());
return (m_cliprgn.intersected(r) == r);
}

View File

@ -107,6 +107,7 @@ public:
QRegion m_alphargn;
QRegion m_cliprgn;
QRegion m_dirtyrgn;
bool m_hasalpha;
bool m_alphaPen;
@ -122,6 +123,9 @@ public:
QPen m_pen;
void addAlphaRect(const QRectF &rect);
void addDirtyRect(const QRectF &rect) { m_dirtyrgn |= rect.toAlignedRect(); }
bool canSeeTroughBackground(bool somethingInRectHasAlpha, const QRectF &rect) const;
QRectF addPenWidth(const QPainterPath &path);
void drawAlphaImage(const QRectF &rect);
QRect toRect(const QRectF &rect) const;

View File

@ -573,7 +573,13 @@ void QWin32PrintEngine::drawPixmap(const QRectF &targetRect,
width = (tw - (x * txinc));
}
QPixmap p = pixmap.copy(tileSize * x, tileSize * y, imgw, imgh);
QImage img(QSize(imgw, imgh), QImage::Format_RGB32);
img.fill(Qt::white);
QPainter painter(&img);
painter.drawPixmap(0,0, pixmap, tileSize * x, tileSize * y, imgw, imgh);
QPixmap p = QPixmap::fromImage(img);
HBITMAP hbitmap = qt_pixmapToWinHBITMAP(p, HBitmapNoAlpha);
HDC display_dc = GetDC(0);
HDC hbitmap_hdc = CreateCompatibleDC(display_dc);