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Do not use libjpeg quantization (bug#74476)

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* src/image.c (jpeg_load_body): Remove libjpeg quantization.
This commit is contained in:
Manuel Giraud 2024-11-21 17:19:59 +01:00 • committed by Alan Third
parent de98b5a24f
commit 8cd4ab7abd
1 changed files with 31 additions and 49 deletions
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80
src/image.c
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@ -8949,9 +8949,8 @@ jpeg_load_body (struct frame *f, struct image *img,
FILE *fp = NULL;
JSAMPARRAY buffer;
int row_stride, x, y;
int width, height;
int i, ir, ig, ib;
unsigned long *colors;
int width, height, ncomp;
int ir, ig, ib;
Emacs_Pix_Container volatile ximg_volatile = NULL;
/* Open the JPEG file. */
@ -9049,12 +9048,17 @@ jpeg_load_body (struct frame *f, struct image *img,
jpeg_read_header (&mgr->cinfo, 1);
/* Customize decompression so that color quantization will be used.
Start decompression. */
mgr->cinfo.quantize_colors = 1;
/* Start decompression. */
jpeg_start_decompress (&mgr->cinfo);
width = img->width = mgr->cinfo.output_width;
height = img->height = mgr->cinfo.output_height;
ncomp = mgr->cinfo.output_components;
if (ncomp > 2)
ir = 0, ig = 1, ib = 2;
else if (ncomp > 1)
ir = 0, ig = 1, ib = 0;
else
ir = 0, ig = 0, ib = 0;
if (!check_image_size (f, width, height))
{
@ -9073,55 +9077,34 @@ jpeg_load_body (struct frame *f, struct image *img,
sys_longjmp (mgr->setjmp_buffer, 1);
}
/* Allocate colors. When color quantization is used,
mgr->cinfo.actual_number_of_colors has been set with the number of
colors generated, and mgr->cinfo.colormap is a two-dimensional array
of color indices in the range 0..mgr->cinfo.actual_number_of_colors.
No more than 255 colors will be generated. */
USE_SAFE_ALLOCA;
{
if (mgr->cinfo.out_color_components > 2)
ir = 0, ig = 1, ib = 2;
else if (mgr->cinfo.out_color_components > 1)
ir = 0, ig = 1, ib = 0;
else
ir = 0, ig = 0, ib = 0;
/* Use the color table mechanism because it handles colors that
cannot be allocated nicely. Such colors will be replaced with
a default color, and we don't have to care about which colors
can be freed safely, and which can't. */
init_color_table ();
SAFE_NALLOCA (colors, 1, mgr->cinfo.actual_number_of_colors);
for (i = 0; i < mgr->cinfo.actual_number_of_colors; ++i)
{
/* Multiply RGB values with 255 because X expects RGB values
in the range 0..0xffff. */
int r = mgr->cinfo.colormap[ir][i] << 8;
int g = mgr->cinfo.colormap[ig][i] << 8;
int b = mgr->cinfo.colormap[ib][i] << 8;
colors[i] = lookup_rgb_color (f, r, g, b);
}
#ifdef COLOR_TABLE_SUPPORT
/* Remember those colors actually allocated. */
img->colors = colors_in_color_table (&img->ncolors);
free_color_table ();
#endif /* COLOR_TABLE_SUPPORT */
}
/* Read pixels. */
row_stride = width * mgr->cinfo.output_components;
/* Allocate scanlines buffer and Emacs color table. */
row_stride = width * ncomp;
buffer = mgr->cinfo.mem->alloc_sarray ((j_common_ptr) &mgr->cinfo,
JPOOL_IMAGE, row_stride, 1);
init_color_table ();
/* Fill the X image from JPEG data. */
for (y = 0; y < height; ++y)
{
jpeg_read_scanlines (&mgr->cinfo, buffer, 1);
for (x = 0; x < mgr->cinfo.output_width; ++x)
PUT_PIXEL (ximg, x, y, colors[buffer[0][x]]);
for (x = 0; x < width; ++x)
{
int off = x * ncomp;
/* Multiply RGB values with 255 because X expects RGB values
in the range 0..0xffff. */
int r = buffer[0][off + ir] << 8;
int g = buffer[0][off + ig] << 8;
int b = buffer[0][off + ib] << 8;
PUT_PIXEL (ximg, x, y, lookup_rgb_color (f, r, g, b));
}
}
#ifdef COLOR_TABLE_SUPPORT
/* Remember those colors actually allocated. */
img->colors = colors_in_color_table (&img->ncolors);
free_color_table ();
#endif /* COLOR_TABLE_SUPPORT */
/* Clean up. */
jpeg_finish_decompress (&mgr->cinfo);
jpeg_destroy_decompress (&mgr->cinfo);
@ -9135,7 +9118,6 @@ jpeg_load_body (struct frame *f, struct image *img,
/* Put ximg into the image. */
image_put_x_image (f, img, ximg, 0);
SAFE_FREE ();
return 1;
}