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@urraka
Last active January 21, 2024 00:20
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#define STB_IMAGE_IMPLEMENTATION
#define STB_IMAGE_WRITE_IMPLEMENTATION
#define STBI_ONLY_PNG
#define STBI_ONLY_JPEG
#define STBI_ONLY_BMP
#define STBI_ONLY_GIF
#include "stb_image.h"
#include "stb_image_write.h"
#ifdef __cplusplus
extern "C" {
#endif
typedef struct gif_result_t {
int delay;
unsigned char *data;
struct gif_result_t *next;
} gif_result;
STBIDEF unsigned char *stbi_xload(char const *filename, int *x, int *y, int *frames)
{
FILE *f;
stbi__context s;
unsigned char *result = 0;
if (!(f = stbi__fopen(filename, "rb")))
return stbi__errpuc("can't fopen", "Unable to open file");
stbi__start_file(&s, f);
if (stbi__gif_test(&s))
{
int c;
stbi__gif g;
gif_result head;
gif_result *prev = 0, *gr = &head;
memset(&g, 0, sizeof(g));
memset(&head, 0, sizeof(head));
*frames = 0;
while (gr->data = stbi__gif_load_next(&s, &g, &c, 4))
{
if (gr->data == (unsigned char*)&s)
{
gr->data = 0;
break;
}
if (prev) prev->next = gr;
gr->delay = g.delay;
prev = gr;
gr = (gif_result*) stbi__malloc(sizeof(gif_result));
memset(gr, 0, sizeof(gif_result));
++(*frames);
}
STBI_FREE(g.out);
if (gr != &head)
STBI_FREE(gr);
if (*frames > 0)
{
*x = g.w;
*y = g.h;
}
result = head.data;
if (*frames > 1)
{
unsigned int size = 4 * g.w * g.h;
unsigned char *p = 0;
result = (unsigned char*)stbi__malloc(*frames * (size + 2));
gr = &head;
p = result;
while (gr)
{
prev = gr;
memcpy(p, gr->data, size);
p += size;
*p++ = gr->delay & 0xFF;
*p++ = (gr->delay & 0xFF00) >> 8;
gr = gr->next;
STBI_FREE(prev->data);
if (prev != &head) STBI_FREE(prev);
}
}
}
else
{
result = stbi__load_main(&s, x, y, frames, 4);
*frames = !!result;
}
fclose(f);
return result;
}
#ifdef __cplusplus
}
#endif
@Platforming-Mayhem
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Platforming-Mayhem commented Nov 20, 2023

@urraka Sorry to bother you, but do u have any idea as to why this is happening when it loads the next frame?
image

image

I also get this exception thrown when loading the next frame on majority of my gifs
image
Some of them don't get this issue, but those are the ones where the gif is created in a specific program, I think it was Adobe Animate CC.
Animated Gifs created in Krita don't work, Animated Gifs created in Photoshop also don't work.

@Platforming-Mayhem
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Nevermind this was my mistake.

@Platforming-Mayhem
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Platforming-Mayhem commented Nov 21, 2023

image
This is how you allow vertical flipping for the gifs :)

@urraka
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urraka commented Nov 22, 2023

Hey @Platforming-Mayhem, looks like you got it working, good to know!

By the way, that last line you're highlighting looks suspicious to me. Isn't stbi_set_flip_vertically_on_load a function? My C/C++ is rusty but I think that might be interpreting it as a pointer and just testing that it's not zero, so stbi__vertical_flip_slices is always called.

@Platforming-Mayhem
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@urraka I'm not sure, since I just copied it from one of the stb_load functions

@urraka
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urraka commented Nov 23, 2023

@Platforming-Mayhem nevermind what I said, my bad. The function is stbi_set_flip_vertically_on_load but you have stbi__vertically_flip_on_load so it's all good ;D

@Platforming-Mayhem
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Hi @urraka,
I've been using this code for a while now but recently I found out that it takes up a lot of memory. Is this normal and is there anyway to decrease the amount of memory that is used?
Thanks :)

@urraka
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urraka commented Jan 4, 2024

Hi @Platforming-Mayhem. The way this works is the easy way out: load every frame into memory in RGBA format. If you have big images with many frames it will take a lot of memory (width * height * 4 * number of frames bytes). I suppose, in theory, one could load the compressed file into memory and buffer a few frames at a time (sort of like video preloading)... but that would need a lot more work.

@Platforming-Mayhem
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Thanks :)
This was a big help :D

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