diff options
author | MihailNaydenov <garfieldhq@yahoo.com> | 2014-09-26 12:23:55 +0300 |
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committer | Tor Arne Vestbø <tor.arne.vestbo@theqtcompany.com> | 2014-12-12 15:32:55 +0100 |
commit | dc583a0576343cfcd5544a21b8625af61e299e6f (patch) | |
tree | 5463f3fdbc4a878009684baa5368a406caddacda /src/gui | |
parent | d47b9ace50d47a4472dc9fb029bbf6e8dd810c01 (diff) |
Fix incorrect QImage transformation when its devicePixelRatio != 1
QImage::transformed compensates for unwanted translation. This compensation
is performed in "pixel space". However, a possible code path to perform the
transformation uses QPainter which is devicePixelRatio-aware and expects the
transformation matrix to be in logical coordinates.
For example, image.transformed(QTransform().rotate(45)) will result in
cropped out image if devicePixelRatio == 2.
Change-Id: I830ff3ffa25531d842dc9c77f1d0e8d4bd502c9d
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@theqtcompany.com>
Diffstat (limited to 'src/gui')
-rw-r--r-- | src/gui/image/qimage.cpp | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/src/gui/image/qimage.cpp b/src/gui/image/qimage.cpp index 4e10b4cb4b..ea23954a49 100644 --- a/src/gui/image/qimage.cpp +++ b/src/gui/image/qimage.cpp @@ -4480,7 +4480,6 @@ QImage QImage::transformed(const QTransform &matrix, Qt::TransformationMode mode dImage.d->dpmx = dotsPerMeterX(); dImage.d->dpmy = dotsPerMeterY(); - dImage.d->devicePixelRatio = devicePixelRatio(); switch (bpp) { // initizialize the data @@ -4502,13 +4501,19 @@ QImage QImage::transformed(const QTransform &matrix, Qt::TransformationMode mode } if (target_format >= QImage::Format_RGB32) { + // Prevent QPainter from applying devicePixelRatio corrections + const QImage sImage = (devicePixelRatio() != 1) ? QImage(constBits(), width(), height(), format()) : *this; + + Q_ASSERT(sImage.devicePixelRatio() == 1); + Q_ASSERT(sImage.devicePixelRatio() == dImage.devicePixelRatio()); + QPainter p(&dImage); if (mode == Qt::SmoothTransformation) { p.setRenderHint(QPainter::Antialiasing); p.setRenderHint(QPainter::SmoothPixmapTransform); } p.setTransform(mat); - p.drawImage(QPoint(0, 0), *this); + p.drawImage(QPoint(0, 0), sImage); } else { bool invertible; mat = mat.inverted(&invertible); // invert matrix @@ -4520,6 +4525,8 @@ QImage QImage::transformed(const QTransform &matrix, Qt::TransformationMode mode int dbpl = dImage.bytesPerLine(); qt_xForm_helper(mat, 0, type, bpp, dImage.bits(), dbpl, 0, hd, sptr, sbpl, ws, hs); } + + dImage.d->devicePixelRatio = devicePixelRatio(); return dImage; } |