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cute_aseprite.h: Added support for indexed and grayscale pixels #423

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cute_aseprite.h: Added support for indexed and grayscale pixels #423

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72 changes: 38 additions & 34 deletions cute_aseprite.h
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Original file line number Diff line number Diff line change
Expand Up @@ -116,6 +116,8 @@ void cute_aseprite_free(ase_t* aseprite);
#include <stdint.h>

typedef struct ase_color_t ase_color_t;
typedef struct ase_grayscale_t ase_grayscale_t;
typedef struct ase_index_t ase_index_t;
typedef struct ase_frame_t ase_frame_t;
typedef struct ase_layer_t ase_layer_t;
typedef struct ase_cel_t ase_cel_t;
Expand All @@ -133,6 +135,16 @@ struct ase_color_t
uint8_t r, g, b, a;
};

struct ase_grayscale_t
{
uint8_t v, a;
};

struct ase_index_t
{
uint8_t i;
};

struct ase_fixed_t
{
uint16_t a;
Expand Down Expand Up @@ -200,7 +212,7 @@ struct ase_frame_t
{
ase_t* ase;
int duration_milliseconds;
ase_color_t* pixels;
void* pixels;
int cel_count;
ase_cel_t cels[CUTE_ASEPRITE_MAX_LAYERS];
};
Expand Down Expand Up @@ -910,31 +922,6 @@ static int s_max(int a, int b)
return a < b ? b : a;
}

static ase_color_t s_color(ase_t* ase, void* src, int index)
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@RandyGaul RandyGaul Feb 4, 2026

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We need to leave a helper function so people can add in their own new blending support. The blending loops below are optional and only added in for convenience. There are many ways to blend aseprite layers together, I just picked the most "typical" to support for now.

{
ase_color_t result;
if (ase->mode == ASE_MODE_RGBA) {
result = ((ase_color_t*)src)[index];
} else if (ase->mode == ASE_MODE_GRAYSCALE) {
uint8_t saturation = ((uint8_t*)src)[index * 2];
uint8_t a = ((uint8_t*)src)[index * 2 + 1];
result.r = result.g = result.b = saturation;
result.a = a;
} else {
CUTE_ASEPRITE_ASSERT(ase->mode == ASE_MODE_INDEXED);
uint8_t palette_index = ((uint8_t*)src)[index];
if (palette_index == ase->transparent_palette_entry_index) {
result.r = 0;
result.g = 0;
result.b = 0;
result.a = 0;
} else {
result = ase->palette.entries[palette_index].color;
}
}
return result;
}

ase_t* cute_aseprite_load_from_memory(const void* memory, int size, void* mem_ctx)
{
ase_t* ase = (ase_t*)CUTE_ASEPRITE_ALLOC(sizeof(ase_t), mem_ctx);
Expand Down Expand Up @@ -1239,9 +1226,18 @@ ase_t* cute_aseprite_load_from_memory(const void* memory, int size, void* mem_ct
// Blend all cel pixels into each of their respective frames, for convenience.
for (int i = 0; i < ase->frame_count; ++i) {
ase_frame_t* frame = ase->frames + i;
frame->pixels = (ase_color_t*)CUTE_ASEPRITE_ALLOC((int)(sizeof(ase_color_t)) * ase->w * ase->h, mem_ctx);
CUTE_ASEPRITE_MEMSET(frame->pixels, 0, sizeof(ase_color_t) * (size_t)ase->w * (size_t)ase->h);
ase_color_t* dst = frame->pixels;
int size;
if (ase->mode == ASE_MODE_RGBA) {
size = (int) (sizeof(ase_color_t)) * ase->w * ase->h;
} else if(ase->mode == ASE_MODE_GRAYSCALE) {
size = (int) (sizeof(ase_grayscale_t)) * ase->w * ase->h;
} else {
CUTE_ASEPRITE_ASSERT(ase->mode == ASE_MODE_INDEXED);
size = (int) (sizeof(ase_index_t)) * ase->w * ase->h;
}
frame->pixels = CUTE_ASEPRITE_ALLOC(size, mem_ctx);
CUTE_ASEPRITE_MEMSET(frame->pixels, 0, size);
void* dst = frame->pixels;
for (int j = 0; j < frame->cel_count; ++j) {
ase_cel_t* cel = frame->cels + j;
if (!(cel->layer->flags & ASE_LAYER_FLAGS_VISIBLE)) {
Expand Down Expand Up @@ -1277,11 +1273,19 @@ ase_t* cute_aseprite_load_from_memory(const void* memory, int size, void* mem_ct
int aw = ase->w;
for (int dx = dl, sx = cl; dx < dr; dx++, sx++) {
for (int dy = dt, sy = ct; dy < db; dy++, sy++) {
int dst_index = aw * dy + dx;
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@RandyGaul RandyGaul Feb 4, 2026

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Did you accidentally delete this?

ase_color_t src_color = s_color(ase, src, cw * sy + sx);
ase_color_t dst_color = dst[dst_index];
ase_color_t result = s_blend(src_color, dst_color, opacity);
dst[dst_index] = result;
if (ase->mode == ASE_MODE_RGBA) {
ase_color_t *d = (ase_color_t *) dst;
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@RandyGaul RandyGaul Feb 4, 2026

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Need to match formatting style for the rest of the file -- (ase_color_t*) not ase_color_t *

ase_color_t src_color = ((ase_color_t *) src)[cw * sy + sx];
ase_color_t dst_color = d[dst_index];
ase_color_t result = s_blend(src_color, dst_color, opacity);
d[dst_index] = result;
} else if (ase->mode == ASE_MODE_GRAYSCALE) {
ase_grayscale_t *d = (ase_grayscale_t *) dst;
d[dst_index] = ((ase_grayscale_t *) src)[cw * sy + sx];
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@RandyGaul RandyGaul Feb 4, 2026

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Formatting: ((ase_grayscale_t *) src) -> ((ase_grayscale_t*)src)

} else {
ase_index_t *d = (ase_index_t *) dst;
d[dst_index] = ((ase_index_t *) src)[cw * sy + sx];
}
}
}
}
Expand Down