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-rw-r--r--fastiv-io.c63
1 files changed, 62 insertions, 1 deletions
diff --git a/fastiv-io.c b/fastiv-io.c
index 5ce8ea3..90560fe 100644
--- a/fastiv-io.c
+++ b/fastiv-io.c
@@ -207,6 +207,7 @@ struct load_wuffs_frame_context {
wuffs_base__io_buffer *src; ///< Wuffs source buffer
wuffs_base__image_config cfg; ///< Wuffs image configuration
wuffs_base__slice_u8 workbuf; ///< Work buffer for Wuffs
+ wuffs_base__frame_config last_fc; ///< Previous frame configuration
uint32_t width; ///< Copied from cfg.pixcfg
uint32_t height; ///< Copied from cfg.pixcfg
cairo_format_t cairo_format; ///< Target format for surfaces
@@ -222,7 +223,7 @@ struct load_wuffs_frame_context {
static bool
load_wuffs_frame(struct load_wuffs_frame_context *ctx, GError **error)
{
- wuffs_base__frame_config fc = {0};
+ wuffs_base__frame_config fc = {};
wuffs_base__status status =
wuffs_base__image_decoder__decode_frame_config(ctx->dec, &fc, ctx->src);
if (status.repr == wuffs_base__note__end_of_data && ctx->result)
@@ -310,6 +311,65 @@ load_wuffs_frame(struct load_wuffs_frame_context *ctx, GError **error)
// Pixel data has been written, need to let Cairo know.
cairo_surface_mark_dirty(surface);
+ // Single-frame images get a fast path, animations are are handled slowly:
+ if (wuffs_base__frame_config__index(&fc) > 0) {
+ // Copy the previous frame to a new surface.
+ cairo_surface_t *canvas = cairo_image_surface_create(
+ ctx->cairo_format, ctx->width, ctx->height);
+ int stride = cairo_image_surface_get_stride(canvas);
+ int height = cairo_image_surface_get_height(canvas);
+ memcpy(cairo_image_surface_get_data(canvas),
+ cairo_image_surface_get_data(ctx->result_tail), stride * height);
+ cairo_surface_mark_dirty(canvas);
+
+ // Apply that frame's disposal method.
+ wuffs_base__rect_ie_u32 bounds =
+ wuffs_base__frame_config__bounds(&ctx->last_fc);
+ wuffs_base__color_u32_argb_premul bg =
+ wuffs_base__frame_config__background_color(&ctx->last_fc);
+
+ double a = (bg >> 24) / 255., r = 0, g = 0, b = 0;
+ if (a) {
+ r = (uint8_t) (bg >> 16) / 255. / a;
+ g = (uint8_t) (bg >> 8) / 255. / a;
+ b = (uint8_t) (bg) / 255. / a;
+ }
+
+ cairo_t *cr = cairo_create(canvas);
+ switch (wuffs_base__frame_config__disposal(&ctx->last_fc)) {
+ case WUFFS_BASE__ANIMATION_DISPOSAL__RESTORE_BACKGROUND:
+ cairo_rectangle(cr, bounds.min_incl_x, bounds.min_incl_y,
+ bounds.max_excl_x - bounds.min_incl_x,
+ bounds.max_excl_y - bounds.min_incl_y);
+ cairo_set_source_rgba(cr, r, g, b, a);
+ cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
+ cairo_fill(cr);
+ break;
+ case WUFFS_BASE__ANIMATION_DISPOSAL__RESTORE_PREVIOUS:
+ // TODO(p): Implement, it seems tricky.
+ // Might need another surface to keep track of the state.
+ break;
+ }
+
+ // Paint the current frame over that, within its bounds.
+ bounds = wuffs_base__frame_config__bounds(&fc);
+ cairo_rectangle(cr, bounds.min_incl_x, bounds.min_incl_y,
+ bounds.max_excl_x - bounds.min_incl_x,
+ bounds.max_excl_y - bounds.min_incl_y);
+ cairo_clip(cr);
+
+ cairo_set_operator(cr,
+ wuffs_base__frame_config__overwrite_instead_of_blend(&fc)
+ ? CAIRO_OPERATOR_SOURCE
+ : CAIRO_OPERATOR_OVER);
+
+ cairo_set_source_surface(cr, surface, 0, 0);
+ cairo_paint(cr);
+ cairo_destroy(cr);
+ cairo_surface_destroy(surface);
+ surface = canvas;
+ }
+
if (ctx->meta_exif)
cairo_surface_set_user_data(surface, &fastiv_io_key_exif,
g_bytes_ref(ctx->meta_exif), (cairo_destroy_func_t) g_bytes_unref);
@@ -334,6 +394,7 @@ load_wuffs_frame(struct load_wuffs_frame_context *ctx, GError **error)
success = true;
ctx->result_tail = surface;
+ ctx->last_fc = fc;
fail:
if (!success) {