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John Alanbrook
2025-12-21 10:38:00 -06:00
parent 8941908553
commit ea3499db51
2 changed files with 48 additions and 19 deletions
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55
gif.c
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@@ -3,7 +3,13 @@
#include <stdlib.h>
#include "stb_image_common.h"
// GIF decoding via stb_image (returns first frame only for animated GIFs)
// GIF decoding via stb_image - handles animated GIFs
// Returns an object with:
// .width, .height - dimensions
// .frames - array of frame objects, each with:
// .width, .height, .format, .pitch, .pixels, .depth, .hdr
// .duration - frame duration in milliseconds (for animated GIFs)
// .frame_count - number of frames
JSValue js_gif_decode(JSContext *js, JSValue this_val, int argc, JSValueConst *argv)
{
size_t len;
@@ -11,31 +17,54 @@ JSValue js_gif_decode(JSContext *js, JSValue this_val, int argc, JSValueConst *a
if (raw == NULL) return JS_EXCEPTION;
if (!raw) return JS_ThrowReferenceError(js, "could not get GIF data from blob");
int n, width, height;
void *data = stbi_load_from_memory(raw, len, &width, &height, &n, 4);
int n, width, height, frames_count;
int *delays = NULL;
void *data = stbi_load_gif_from_memory(raw, len, &delays, &width, &height, &frames_count, &n, 4);
if (!data)
return JS_ThrowReferenceError(js, "failed to decode GIF: %s", stbi_failure_reason());
if (width <= 0 || height <= 0) {
stbi_image_free(data);
if (delays) stbi_image_free(delays);
return JS_ThrowReferenceError(js, "decoded GIF has invalid size: %dx%d", width, height);
}
int pitch = width * 4;
size_t pixels_size = pitch * height;
size_t frame_size = pitch * height;
JSValue obj = JS_NewObject(js);
JS_SetPropertyStr(js, obj, "width", JS_NewInt32(js, width));
JS_SetPropertyStr(js, obj, "height", JS_NewInt32(js, height));
JS_SetPropertyStr(js, obj, "format", JS_NewString(js, "rgba32"));
JS_SetPropertyStr(js, obj, "pitch", JS_NewInt32(js, pitch));
JS_SetPropertyStr(js, obj, "pixels", js_new_blob_stoned_copy(js, data, pixels_size));
JS_SetPropertyStr(js, obj, "depth", JS_NewInt32(js, 8));
JS_SetPropertyStr(js, obj, "hdr", JS_NewBool(js, 0));
// Create frames array
JSValue frames_array = JS_NewArray(js);
for (int i = 0; i < frames_count; i++) {
JSValue frame = JS_NewObject(js);
JS_SetPropertyStr(js, frame, "width", JS_NewInt32(js, width));
JS_SetPropertyStr(js, frame, "height", JS_NewInt32(js, height));
JS_SetPropertyStr(js, frame, "format", JS_NewString(js, "rgba32"));
JS_SetPropertyStr(js, frame, "pitch", JS_NewInt32(js, pitch));
void *frame_pixels = (unsigned char*)data + (frame_size * i);
JS_SetPropertyStr(js, frame, "pixels", js_new_blob_stoned_copy(js, frame_pixels, frame_size));
JS_SetPropertyStr(js, frame, "depth", JS_NewInt32(js, 8));
JS_SetPropertyStr(js, frame, "hdr", JS_NewBool(js, 0));
// Add duration in milliseconds (delays are in centiseconds, i.e. 1/100th of a second)
int duration_ms = delays ? delays[i] * 10 : 100;
JS_SetPropertyStr(js, frame, "duration", JS_NewInt32(js, duration_ms));
JS_SetPropertyUint32(js, frames_array, i, frame);
}
// Create result object
JSValue result = JS_NewObject(js);
JS_SetPropertyStr(js, result, "width", JS_NewInt32(js, width));
JS_SetPropertyStr(js, result, "height", JS_NewInt32(js, height));
JS_SetPropertyStr(js, result, "frames", frames_array);
JS_SetPropertyStr(js, result, "frame_count", JS_NewInt32(js, frames_count));
stbi_image_free(data);
return obj;
if (delays) stbi_image_free(delays);
return result;
}
static const JSCFunctionListEntry js_gif_funcs[] = {