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| author | Michael Drake <tlsa@netsurf-browser.org> | 2021-10-31 17:11:15 +0000 |
|---|---|---|
| committer | Michael Drake <tlsa@netsurf-browser.org> | 2021-10-31 17:11:57 +0000 |
| commit | 46d7a0bb13a36dabaa5ede2158d22e3e702f5ad2 (patch) | |
| tree | 0e0e262f9afbb2c686871bb515270b9add5b1be6 /src | |
| parent | 8eac839eed55432446077659c052b6459509af2a (diff) | |
| download | libnsgif-46d7a0bb13a36dabaa5ede2158d22e3e702f5ad2.tar.gz libnsgif-46d7a0bb13a36dabaa5ede2158d22e3e702f5ad2.tar.bz2 | |
GIF: Use cached frame details for clear disposal handling.
Diffstat (limited to 'src')
| -rw-r--r-- | src/libnsgif.c | 37 |
1 files changed, 5 insertions, 32 deletions
diff --git a/src/libnsgif.c b/src/libnsgif.c index 3cb1135..e744bcf 100644 --- a/src/libnsgif.c +++ b/src/libnsgif.c @@ -832,37 +832,11 @@ gif_clear_frame(gif_animation *gif, unsigned int frame) goto gif_decode_frame_exit; } - /* 10-byte Image Descriptor is: - * - * +0 CHAR Image Separator (0x2c) - * +1 SHORT Image Left Position - * +3 SHORT Image Top Position - * +5 SHORT Width - * +7 SHORT Height - * +9 CHAR __Packed Fields__ - * 1BIT Local Colour Table Flag - * 1BIT Interlace Flag - * 1BIT Sort Flag - * 2BITS Reserved - * 3BITS Size of Local Colour Table - */ - if (gif_data[0] != GIF_IMAGE_SEPARATOR) { - return_value = GIF_DATA_ERROR; - goto gif_decode_frame_exit; - } - offset_x = gif_data[1] | (gif_data[2] << 8); - offset_y = gif_data[3] | (gif_data[4] << 8); - width = gif_data[5] | (gif_data[6] << 8); - height = gif_data[7] | (gif_data[8] << 8); - - /* Boundary checking - shouldn't ever happen except unless the data has - * been modified since initialisation. - */ - if ((offset_x + width > gif->width) || - (offset_y + height > gif->height)) { - return_value = GIF_DATA_ERROR; - goto gif_decode_frame_exit; - } + offset_x = gif->frames[frame].redraw_x; + offset_y = gif->frames[frame].redraw_y; + width = gif->frames[frame].redraw_width; + height = gif->frames[frame].redraw_height; + flags = gif->frames[frame].flags; /* Make sure we have a buffer to decode to. */ @@ -871,7 +845,6 @@ gif_clear_frame(gif_animation *gif, unsigned int frame) } /* Decode the flags */ - flags = gif_data[9]; colour_table_size = 2 << (flags & GIF_COLOUR_TABLE_SIZE_MASK); /* Advance data pointer to next block either colour table or image |