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Fix GIF decoding for certain files 

The handling is not perfect yet, but it should be fine enough.
This commit is contained in:
Přemysl Eric Janouch 2022-01-08 05:32:42 +01:00
parent 231b77e6c0
commit b973d323ba
Signed by: p
GPG Key ID: A0420B94F92B9493
1 changed files with 13 additions and 3 deletions
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16
fiv-io.c
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@ -564,10 +564,17 @@ load_wuffs_frame(struct load_wuffs_frame_context *ctx, GError **error)
return false; return false;
} }
// Wuffs' test/data/animated-red-blue.gif, e.g., needs this handling.
cairo_format_t decode_format = ctx->cairo_format;
if (wuffs_base__frame_config__index(&fc) > 0 &&
wuffs_base__pixel_config__pixel_format(&ctx->cfg.pixcfg).repr ==
WUFFS_BASE__PIXEL_FORMAT__BGRA_NONPREMUL)
decode_format = CAIRO_FORMAT_ARGB32;
bool success = false; bool success = false;
unsigned char *targetbuf = NULL; unsigned char *targetbuf = NULL;
cairo_surface_t *surface = cairo_surface_t *surface =
cairo_image_surface_create(ctx->cairo_format, ctx->width, ctx->height); cairo_image_surface_create(decode_format, ctx->width, ctx->height);
cairo_status_t surface_status = cairo_surface_status(surface); cairo_status_t surface_status = cairo_surface_status(surface);
if (surface_status != CAIRO_STATUS_SUCCESS) { if (surface_status != CAIRO_STATUS_SUCCESS) {
set_error(error, cairo_status_to_string(surface_status)); set_error(error, cairo_status_to_string(surface_status));
@ -659,6 +666,7 @@ load_wuffs_frame(struct load_wuffs_frame_context *ctx, GError **error)
cairo_surface_mark_dirty(canvas); cairo_surface_mark_dirty(canvas);
// Apply that frame's disposal method. // Apply that frame's disposal method.
// XXX: We do not expect opaque pictures to receive holes this way.
wuffs_base__rect_ie_u32 bounds = wuffs_base__rect_ie_u32 bounds =
wuffs_base__frame_config__bounds(&ctx->last_fc); wuffs_base__frame_config__bounds(&ctx->last_fc);
// TODO(p): This field needs to be colour-managed. // TODO(p): This field needs to be colour-managed.
@ -686,6 +694,8 @@ load_wuffs_frame(struct load_wuffs_frame_context *ctx, GError **error)
// TODO(p): Implement, it seems tricky. // TODO(p): Implement, it seems tricky.
// Might need another surface to keep track of the state. // Might need another surface to keep track of the state.
break; break;
case WUFFS_BASE__ANIMATION_DISPOSAL__NONE:
break;
} }
// Paint the current frame over that, within its bounds. // Paint the current frame over that, within its bounds.
@ -844,8 +854,6 @@ open_wuffs(wuffs_base__image_decoder *dec, wuffs_base__io_buffer src,
// Wuffs maps tRNS to BGRA in `decoder.decode_trns?`, we should be fine. // Wuffs maps tRNS to BGRA in `decoder.decode_trns?`, we should be fine.
// wuffs_base__pixel_format__transparency() doesn't reflect the image file. // wuffs_base__pixel_format__transparency() doesn't reflect the image file.
// TODO(p): See if wuffs_base__image_config__first_frame_is_opaque() causes
// issues with animations, and eventually ensure an alpha-capable format.
bool opaque = wuffs_base__image_config__first_frame_is_opaque(&ctx.cfg); bool opaque = wuffs_base__image_config__first_frame_is_opaque(&ctx.cfg);
// Wuffs' API is kind of awful--we want to catch wide RGB and wide grey. // Wuffs' API is kind of awful--we want to catch wide RGB and wide grey.
@ -886,6 +894,8 @@ open_wuffs(wuffs_base__image_decoder *dec, wuffs_base__io_buffer src,
ctx.cairo_format = CAIRO_FORMAT_RGB30; ctx.cairo_format = CAIRO_FORMAT_RGB30;
} else if (opaque) { } else if (opaque) {
// BGRX doesn't have as wide swizzler support, namely in GIF. // BGRX doesn't have as wide swizzler support, namely in GIF.
// Moreover, follower frames may still be partly transparent.
// Therefore, we choose to keep "wuffs_format" intact.
ctx.cairo_format = CAIRO_FORMAT_RGB24; ctx.cairo_format = CAIRO_FORMAT_RGB24;
} else if (!ctx.target) { } else if (!ctx.target) {
wuffs_format = WUFFS_BASE__PIXEL_FORMAT__BGRA_PREMUL; wuffs_format = WUFFS_BASE__PIXEL_FORMAT__BGRA_PREMUL;