From d91c1422a9d0b96172fb13da5a179688b590d125 Mon Sep 17 00:00:00 2001 From: aavit Date: Wed, 7 Nov 2012 15:19:20 +0100 Subject: 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 (cherry picked from qt/c309d424f45dc0e7b62fbbbabf20dbfe355f48a7) Reviewed-by: aavit --- src/gui/image/qgifhandler.cpp | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) (limited to 'src') 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; } //------------------------------------------------------------------------- -- cgit v1.2.3