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JPEG: Handle errors when saving with libjpeg #431

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merged 2 commits into from
Mar 11, 2024
Merged

JPEG: Handle errors when saving with libjpeg #431

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56a1f39
JPEG: Factor out the middle of IMG_SaveJPG_RW_jpeglib
smcv Mar 11, 2024
ac5f692
JPEG: Add error-recovery when saving with libjpeg
smcv Mar 11, 2024
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81 changes: 52 additions & 29 deletions src/IMG_jpg.c
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Original file line number Diff line number Diff line change
Expand Up @@ -478,15 +478,61 @@ static void jpeg_SDL_RW_dest(j_compress_ptr cinfo, SDL_RWops *ctx)
dest->pub.free_in_buffer = OUTPUT_BUFFER_SIZE;
}

struct savejpeg_vars
{
struct jpeg_compress_struct cinfo;
struct my_error_mgr jerr;
Sint64 original_offset;
};

static int JPEG_SaveJPEG_RW(struct savejpeg_vars *vars, SDL_Surface *jpeg_surface, SDL_RWops *dst, int quality)
{
/* Create a compression structure and load the JPEG header */
vars->cinfo.err = lib.jpeg_std_error(&vars->jerr.errmgr);
vars->jerr.errmgr.error_exit = my_error_exit;
vars->jerr.errmgr.output_message = output_no_message;
vars->original_offset = SDL_RWtell(dst);

if(setjmp(vars->jerr.escape)) {
/* If we get here, libjpeg found an error */
lib.jpeg_destroy_compress(&vars->cinfo);
SDL_RWseek(dst, vars->original_offset, SDL_RW_SEEK_SET);
return IMG_SetError("Error saving JPEG with libjpeg");
}

lib.jpeg_create_compress(&vars->cinfo);
jpeg_SDL_RW_dest(&vars->cinfo, dst);

vars->cinfo.image_width = jpeg_surface->w;
vars->cinfo.image_height = jpeg_surface->h;
vars->cinfo.in_color_space = JCS_RGB;
vars->cinfo.input_components = 3;

lib.jpeg_set_defaults(&vars->cinfo);
lib.jpeg_set_quality(&vars->cinfo, quality, TRUE);
lib.jpeg_start_compress(&vars->cinfo, TRUE);

while (vars->cinfo.next_scanline < vars->cinfo.image_height) {
JSAMPROW row_pointer[1];
int offset = vars->cinfo.next_scanline * jpeg_surface->pitch;

row_pointer[0] = ((Uint8*)jpeg_surface->pixels) + offset;
lib.jpeg_write_scanlines(&vars->cinfo, row_pointer, 1);
}

lib.jpeg_finish_compress(&vars->cinfo);
lib.jpeg_destroy_compress(&vars->cinfo);
return 0;
}

static int IMG_SaveJPG_RW_jpeglib(SDL_Surface *surface, SDL_RWops *dst, int quality)
{
/* The JPEG library reads bytes in R,G,B order, so this is the right
* encoding for either endianness */
struct savejpeg_vars vars;
static const Uint32 jpg_format = SDL_PIXELFORMAT_RGB24;
struct jpeg_compress_struct cinfo;
struct my_error_mgr jerr;
JSAMPROW row_pointer[1];
SDL_Surface* jpeg_surface = surface;
int ret;

if (!IMG_Init(IMG_INIT_JPG)) {
return -1;
Expand All @@ -500,36 +546,13 @@ static int IMG_SaveJPG_RW_jpeglib(SDL_Surface *surface, SDL_RWops *dst, int qual
}
}

/* Create a decompression structure and load the JPEG header */
cinfo.err = lib.jpeg_std_error(&jerr.errmgr);
jerr.errmgr.error_exit = my_error_exit;
jerr.errmgr.output_message = output_no_message;

lib.jpeg_create_compress(&cinfo);
jpeg_SDL_RW_dest(&cinfo, dst);

cinfo.image_width = jpeg_surface->w;
cinfo.image_height = jpeg_surface->h;
cinfo.in_color_space = JCS_RGB;
cinfo.input_components = 3;

lib.jpeg_set_defaults(&cinfo);
lib.jpeg_set_quality(&cinfo, quality, TRUE);
lib.jpeg_start_compress(&cinfo, TRUE);

while (cinfo.next_scanline < cinfo.image_height) {
int offset = cinfo.next_scanline * jpeg_surface->pitch;
row_pointer[0] = ((Uint8*)jpeg_surface->pixels) + offset;
lib.jpeg_write_scanlines(&cinfo, row_pointer, 1);
}

lib.jpeg_finish_compress(&cinfo);
lib.jpeg_destroy_compress(&cinfo);
SDL_zero(vars);
ret = JPEG_SaveJPEG_RW(&vars, jpeg_surface, dst, quality);

if (jpeg_surface != surface) {
SDL_DestroySurface(jpeg_surface);
}
return 0;
return ret;
}

#elif defined(USE_STBIMAGE)
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