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authorAllan Sandfeld Jensen <allan.jensen@digia.com>2014-07-24 15:54:58 +0200
committerAllan Sandfeld Jensen <allan.jensen@digia.com>2014-07-31 20:16:09 +0200
commitd8dc664b945d8832eab97c5df0e1ea47ebf895fd (patch)
treebe9fe35ad391540c7fc8e328d22cc01b5e4592da /src
parent1852ece715b6eefadd8c9bf048d5f8d147f08b5b (diff)
Ensure valid data after QImage::invertPixels
QImage::invertPixels may produce invalid data after inversions of images with premultiplied alpha, because the inverted colors will be larger than the alpha. This patch converts any image with a premultiplied alpha channel to ARGB32 before inverting the pixels, and then back to the original format after the inversion. Support is added for correct inversion of RGBA8888 and RGB30 formats. Task-number: QTBUG-39901 Change-Id: Ief24c55f495e67ef2ad6429b5b418d02963a64dd Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>
Diffstat (limited to 'src')
-rw-r--r--src/gui/image/qimage.cpp50
1 files changed, 47 insertions, 3 deletions
diff --git a/src/gui/image/qimage.cpp b/src/gui/image/qimage.cpp
index 8c7c446e96..0d10dd77d2 100644
--- a/src/gui/image/qimage.cpp
+++ b/src/gui/image/qimage.cpp
@@ -1806,6 +1806,9 @@ void QImage::fill(const QColor &color)
is the case for a 1-bit image. Note that the color table is \e not
changed.
+ If the image has a premultiplied alpha channel, the image is first
+ converted to ARGB32 to be inverted and then converted back.
+
\sa {QImage#Image Transformations}{Image Transformations}
*/
@@ -1820,8 +1823,15 @@ void QImage::invertPixels(InvertMode mode)
if (!d)
return;
- if (depth() != 32) {
- // number of used bytes pr line
+ QImage::Format originalFormat = d->format;
+ // Inverting premultiplied pixels would produce invalid image data.
+ if (hasAlphaChannel() && qPixelLayouts[d->format].premultiplied) {
+ if (!d->convertInPlace(QImage::Format_ARGB32, 0))
+ *this = convertToFormat(QImage::Format_ARGB32);
+ }
+
+ if (depth() < 32) {
+ // This assumes no alpha-channel as the only formats with non-premultipled alpha are 32bit.
int bpl = (d->width * d->depth + 7) / 8;
int pad = d->bytes_per_line - bpl;
uchar *sl = d->data;
@@ -1833,10 +1843,44 @@ void QImage::invertPixels(InvertMode mode)
} else {
quint32 *p = (quint32*)d->data;
quint32 *end = (quint32*)(d->data + d->nbytes);
- uint xorbits = (mode == InvertRgba) ? 0xffffffff : 0x00ffffff;
+ quint32 xorbits = 0xffffffff;
+ switch (d->format) {
+ case QImage::Format_RGBA8888:
+ if (mode == InvertRgba)
+ break;
+ // no break
+ case QImage::Format_RGBX8888:
+#if Q_BYTE_ORDER == Q_BIG_ENDIAN
+ xorbits = 0xffffff00;
+ break;
+#else
+ xorbits = 0x00ffffff;
+ break;
+#endif
+ case QImage::Format_ARGB32:
+ if (mode == InvertRgba)
+ break;
+ // no break
+ case QImage::Format_RGB32:
+ xorbits = 0x00ffffff;
+ break;
+ case QImage::Format_BGR30:
+ case QImage::Format_RGB30:
+ xorbits = 0x3fffffff;
+ break;
+ default:
+ Q_UNREACHABLE();
+ xorbits = 0;
+ break;
+ }
while (p < end)
*p++ ^= xorbits;
}
+
+ if (originalFormat != d->format) {
+ if (!d->convertInPlace(originalFormat, 0))
+ *this = convertToFormat(originalFormat);
+ }
}
// Windows defines these