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| author | Michael Drake <tlsa@netsurf-browser.org> | 2021-11-03 14:44:03 +0000 |
|---|---|---|
| committer | Michael Drake <tlsa@netsurf-browser.org> | 2021-11-03 14:44:03 +0000 |
| commit | 0f7bcedeedff2cdee82644213741b5b96d655d92 (patch) | |
| tree | f419b43103a8eaf152eadc261449b6f627cb506d | |
| parent | 22b5b8f627a770172fbcc9e37656dcf40836f5df (diff) | |
| download | libnsgif-0f7bcedeedff2cdee82644213741b5b96d655d92.tar.gz libnsgif-0f7bcedeedff2cdee82644213741b5b96d655d92.tar.bz2 | |
GIF: Align disposal methods with spec.
| -rw-r--r-- | src/libnsgif.c | 29 |
1 files changed, 16 insertions, 13 deletions
diff --git a/src/libnsgif.c b/src/libnsgif.c index 9001941..fb1c675 100644 --- a/src/libnsgif.c +++ b/src/libnsgif.c @@ -45,12 +45,15 @@ /** No transparency */ #define GIF_NO_TRANSPARENCY (0xFFFFFFFFu) -/* GIF Flags */ -#define GIF_FRAME_COMBINE 1 -#define GIF_FRAME_CLEAR 2 -#define GIF_FRAME_RESTORE 3 -#define GIF_FRAME_QUIRKS_RESTORE 4 +enum gif_disposal { + GIF_DISPOSAL_UNSPECIFIED, + GIF_DISPOSAL_NONE, + GIF_DISPOSAL_RESTORE_BG, + GIF_DISPOSAL_RESTORE_PREV, + GIF_DISPOSAL_RESTORE_QUIRK, /**< Alias for GIF_DISPOSAL_RESTORE_PREV. */ +}; +/* GIF Flags */ #define GIF_INTERLACE_MASK 0x40 #define GIF_COLOUR_TABLE_MASK 0x80 #define GIF_COLOUR_TABLE_SIZE_MASK 0x07 @@ -138,15 +141,15 @@ static gif_result gif__parse_extension_graphic_control( * believe some (older?) software may even actually * export this way. We handle this as a type of * "quirks" mode. */ - if (frame->disposal_method == GIF_FRAME_QUIRKS_RESTORE) { - frame->disposal_method = GIF_FRAME_RESTORE; + if (frame->disposal_method == GIF_DISPOSAL_RESTORE_QUIRK) { + frame->disposal_method = GIF_DISPOSAL_RESTORE_PREV; } /* if we are clearing the background then we need to * redraw enough to cover the previous frame too. */ frame->redraw_required = - frame->disposal_method == GIF_FRAME_CLEAR || - frame->disposal_method == GIF_FRAME_RESTORE; + frame->disposal_method == GIF_DISPOSAL_RESTORE_BG || + frame->disposal_method == GIF_DISPOSAL_RESTORE_PREV; return GIF_OK; } @@ -855,7 +858,7 @@ static void gif_clear_frame( uint32_t offset_x; uint32_t offset_y; - assert(frame->disposal_method == GIF_FRAME_CLEAR); + assert(frame->disposal_method == GIF_DISPOSAL_RESTORE_BG); /* Ensure this frame is supposed to be decoded */ if (frame->display == false) { @@ -1010,10 +1013,10 @@ gif_internal_decode_frame(gif_animation *gif, } else { struct gif_frame *prev = &gif->frames[frame_idx - 1]; - if (prev->disposal_method == GIF_FRAME_CLEAR) { + if (prev->disposal_method == GIF_DISPOSAL_RESTORE_BG) { gif_clear_frame(gif, prev, frame_data); - } else if (prev->disposal_method == GIF_FRAME_RESTORE) { + } else if (prev->disposal_method == GIF_DISPOSAL_RESTORE_PREV) { /* * If the previous frame's disposal method requires we * restore the previous image, restore our saved image. @@ -1025,7 +1028,7 @@ gif_internal_decode_frame(gif_animation *gif, } } - if (frame->disposal_method == GIF_FRAME_RESTORE) { + if (frame->disposal_method == GIF_DISPOSAL_RESTORE_PREV) { /* Store the previous frame for later restoration */ gif__record_frame(gif); } |