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authoraavit <eirik.aavitsland@digia.com>2012-11-07 15:19:20 +0100
committerThe Qt Project <gerrit-noreply@qt-project.org>2012-11-09 16:07:51 +0100
commitd91c1422a9d0b96172fb13da5a179688b590d125 (patch)
tree9aff422dd03654899306ec0f7099a4c268881a6d /src
parentf4a8e940eda1904ed2fba247c1d2752106ccc5c9 (diff)
Fix GIF image decoding: do not zero transparent pixels
For the special transparent color index, the decoder would skip writing anything out (thus leaving the pixels at 0 rgba value). Although correct for later frames, for the initial frame this would loose the color information for such pixels (which one otherwise could have made visible e.g. by converting then image to an alpha-less image format). Change-Id: I316cefce8f21797feedebfbf98296ad84eaa4b99 Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com> (cherry picked from qt/c309d424f45dc0e7b62fbbbabf20dbfe355f48a7) Reviewed-by: aavit <eirik.aavitsland@digia.com>
Diffstat (limited to 'src')
-rw-r--r--src/gui/image/qgifhandler.cpp15
1 files changed, 6 insertions, 9 deletions
diff --git a/src/gui/image/qgifhandler.cpp b/src/gui/image/qgifhandler.cpp
index cedb27c193..b60d1a1711 100644
--- a/src/gui/image/qgifhandler.cpp
+++ b/src/gui/image/qgifhandler.cpp
@@ -488,7 +488,7 @@ int QGIFFormat::decode(QImage *image, const uchar *buffer, int length,
} else {
if (needfirst) {
firstcode=oldcode=code;
- if (!out_of_bounds && image->height() > y && firstcode!=trans_index)
+ if (!out_of_bounds && image->height() > y && ((frame == 0) || (firstcode != trans_index)))
((QRgb*)FAST_SCAN_LINE(bits, bpl, y))[x] = color(firstcode);
x++;
if (x>=swidth) out_of_bounds = true;
@@ -540,17 +540,13 @@ int QGIFFormat::decode(QImage *image, const uchar *buffer, int length,
}
oldcode=incode;
const int h = image->height();
- const QRgb *map = lcmap ? localcmap : globalcmap;
QRgb *line = 0;
if (!out_of_bounds && h > y)
line = (QRgb*)FAST_SCAN_LINE(bits, bpl, y);
while (sp>stack) {
const uchar index = *(--sp);
- if (!out_of_bounds && h > y && index!=trans_index) {
- if (index > ncols)
- line[x] = Q_TRANSPARENT;
- else
- line[x] = map ? map[index] : 0;
+ if (!out_of_bounds && h > y && ((frame == 0) || (index != trans_index))) {
+ line[x] = color(index);
}
x++;
if (x>=swidth) out_of_bounds = true;
@@ -1031,11 +1027,12 @@ void QGIFFormat::nextY(unsigned char *bits, int bpl)
inline QRgb QGIFFormat::color(uchar index) const
{
- if (index == trans_index || index > ncols)
+ if (index > ncols)
return Q_TRANSPARENT;
QRgb *map = lcmap ? localcmap : globalcmap;
- return map ? map[index] : 0;
+ QRgb col = map ? map[index] : 0;
+ return index == trans_index ? col & Q_TRANSPARENT : col;
}
//-------------------------------------------------------------------------