diff options
Diffstat (limited to 'rdgif.c')
-rw-r--r-- | rdgif.c | 59 |
1 files changed, 42 insertions, 17 deletions
@@ -5,7 +5,7 @@ * Copyright (C) 1991-1997, Thomas G. Lane. * Modified 2019 by Guido Vollbeding. * libjpeg-turbo Modifications: - * Copyright (C) 2021, D. R. Commander. + * Copyright (C) 2021-2022, D. R. Commander. * For conditions of distribution and use, see the accompanying README.ijg * file. * @@ -45,7 +45,7 @@ typedef unsigned char U_CHAR; #define ReadOK(file, buffer, len) \ - (JFREAD(file, buffer, len) == ((size_t)(len))) + (fread(buffer, 1, len, file) == ((size_t)(len))) #define MAXCOLORMAPSIZE 256 /* max # of colors in a GIF colormap */ @@ -345,7 +345,7 @@ LOCAL(void) ReadColorMap(gif_source_ptr sinfo, int cmaplen, JSAMPARRAY cmap) /* Read a GIF colormap */ { - int i; + int i, gray = 1; for (i = 0; i < cmaplen; i++) { #if BITS_IN_JSAMPLE == 8 @@ -356,6 +356,14 @@ ReadColorMap(gif_source_ptr sinfo, int cmaplen, JSAMPARRAY cmap) cmap[CM_RED][i] = (JSAMPLE)UPSCALE(ReadByte(sinfo)); cmap[CM_GREEN][i] = (JSAMPLE)UPSCALE(ReadByte(sinfo)); cmap[CM_BLUE][i] = (JSAMPLE)UPSCALE(ReadByte(sinfo)); + if (cmap[CM_RED][i] != cmap[CM_GREEN][i] || + cmap[CM_GREEN][i] != cmap[CM_BLUE][i]) + gray = 0; + } + + if (sinfo->cinfo->in_color_space == JCS_RGB && gray) { + sinfo->cinfo->in_color_space = JCS_GRAYSCALE; + sinfo->cinfo->input_components = 1; } } @@ -516,10 +524,15 @@ start_input_gif(j_compress_ptr cinfo, cjpeg_source_ptr sinfo) source->pub.get_pixel_rows = get_pixel_rows; } + if (cinfo->in_color_space != JCS_GRAYSCALE) { + cinfo->in_color_space = JCS_RGB; + cinfo->input_components = NUMCOLORS; + } + /* Create compressor input buffer. */ source->pub.buffer = (*cinfo->mem->alloc_sarray) - ((j_common_ptr)cinfo, JPOOL_IMAGE, (JDIMENSION)width * NUMCOLORS, - (JDIMENSION)1); + ((j_common_ptr)cinfo, JPOOL_IMAGE, + (JDIMENSION)width * cinfo->input_components, (JDIMENSION)1); source->pub.buffer_height = 1; /* Pad colormap for safety. */ @@ -530,8 +543,6 @@ start_input_gif(j_compress_ptr cinfo, cjpeg_source_ptr sinfo) } /* Return info about the image. */ - cinfo->in_color_space = JCS_RGB; - cinfo->input_components = NUMCOLORS; cinfo->data_precision = BITS_IN_JSAMPLE; /* we always rescale data to this */ cinfo->image_width = width; cinfo->image_height = height; @@ -556,11 +567,18 @@ get_pixel_rows(j_compress_ptr cinfo, cjpeg_source_ptr sinfo) register JSAMPARRAY colormap = source->colormap; ptr = source->pub.buffer[0]; - for (col = cinfo->image_width; col > 0; col--) { - c = LZWReadByte(source); - *ptr++ = colormap[CM_RED][c]; - *ptr++ = colormap[CM_GREEN][c]; - *ptr++ = colormap[CM_BLUE][c]; + if (cinfo->in_color_space == JCS_GRAYSCALE) { + for (col = cinfo->image_width; col > 0; col--) { + c = LZWReadByte(source); + *ptr++ = colormap[CM_RED][c]; + } + } else { + for (col = cinfo->image_width; col > 0; col--) { + c = LZWReadByte(source); + *ptr++ = colormap[CM_RED][c]; + *ptr++ = colormap[CM_GREEN][c]; + *ptr++ = colormap[CM_BLUE][c]; + } } return 1; } @@ -646,11 +664,18 @@ get_interlaced_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo) FALSE); /* Scan the row, expand colormap, and output */ ptr = source->pub.buffer[0]; - for (col = cinfo->image_width; col > 0; col--) { - c = *sptr++; - *ptr++ = colormap[CM_RED][c]; - *ptr++ = colormap[CM_GREEN][c]; - *ptr++ = colormap[CM_BLUE][c]; + if (cinfo->in_color_space == JCS_GRAYSCALE) { + for (col = cinfo->image_width; col > 0; col--) { + c = *sptr++; + *ptr++ = colormap[CM_RED][c]; + } + } else { + for (col = cinfo->image_width; col > 0; col--) { + c = *sptr++; + *ptr++ = colormap[CM_RED][c]; + *ptr++ = colormap[CM_GREEN][c]; + *ptr++ = colormap[CM_BLUE][c]; + } } source->cur_row_number++; /* for next time */ return 1; |