127 lines
3.7 KiB
C
127 lines
3.7 KiB
C
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#include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */
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#ifdef PNG_SUPPORTED
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#include <png.h> /* if this fails, you need to install libpng-devel */
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typedef struct png_source_struct {
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struct cjpeg_source_struct pub;
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png_structp png_ptr;
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png_infop info_ptr;
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JDIMENSION current_row;
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} png_source_struct;
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METHODDEF(void)
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finish_input_png (j_compress_ptr cinfo, cjpeg_source_ptr sinfo);
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METHODDEF(JDIMENSION)
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get_pixel_rows_png (j_compress_ptr cinfo, cjpeg_source_ptr sinfo);
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METHODDEF(void)
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start_input_png (j_compress_ptr cinfo, cjpeg_source_ptr sinfo);
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GLOBAL(cjpeg_source_ptr)
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jinit_read_png(j_compress_ptr cinfo)
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{
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png_source_struct *source = (*cinfo->mem->alloc_small)((j_common_ptr) cinfo, JPOOL_IMAGE, sizeof(png_source_struct));
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memset(source, 0, sizeof(*source));
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/* Fill in method ptrs, except get_pixel_rows which start_input sets */
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source->pub.start_input = start_input_png;
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source->pub.finish_input = finish_input_png;
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return &source->pub;
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}
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METHODDEF(void) error_input_png(png_structp png_ptr, png_const_charp msg) {
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j_compress_ptr cinfo = png_get_error_ptr(png_ptr);
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ERREXITS(cinfo, JERR_PNG_ERROR, msg);
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}
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METHODDEF(void)
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start_input_png (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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{
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png_source_struct *source = (png_source_struct *)sinfo;
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source->png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, cinfo, error_input_png, NULL);
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source->info_ptr = png_create_info_struct(source->png_ptr);
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if (!source->png_ptr || !source->info_ptr) {
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ERREXITS(cinfo, JERR_PNG_ERROR, "Can't create read/info_struct");
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return;
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}
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png_set_palette_to_rgb(source->png_ptr);
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png_set_expand_gray_1_2_4_to_8(source->png_ptr);
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png_set_strip_alpha(source->png_ptr);
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png_set_interlace_handling(source->png_ptr);
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png_init_io(source->png_ptr, source->pub.input_file);
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png_read_info(source->png_ptr, source->info_ptr);
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png_uint_32 width, height;
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int bit_depth, color_type;
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png_get_IHDR(source->png_ptr, source->info_ptr, &width, &height,
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&bit_depth, &color_type, NULL, NULL, NULL);
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if (width > 65535 || height > 65535) {
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ERREXITS(cinfo, JERR_PNG_ERROR, "Image too large");
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return;
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}
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if (color_type == PNG_COLOR_TYPE_GRAY || color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
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cinfo->in_color_space = JCS_GRAYSCALE;
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cinfo->input_components = 1;
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} else {
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cinfo->in_color_space = JCS_RGB;
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cinfo->input_components = 3;
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}
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if (bit_depth == 16) {
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png_set_strip_16(source->png_ptr);
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}
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cinfo->data_precision = 8;
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cinfo->image_width = width;
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cinfo->image_height = height;
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double gamma = 0.45455;
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if (!png_get_valid(source->png_ptr, source->info_ptr, PNG_INFO_sRGB)) {
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png_get_gAMA(source->png_ptr, source->info_ptr, &gamma);
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}
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cinfo->input_gamma = gamma;
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sinfo->get_pixel_rows = get_pixel_rows_png;
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png_read_update_info(source->png_ptr, source->info_ptr);
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png_size_t rowbytes = png_get_rowbytes(source->png_ptr, source->info_ptr);
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source->pub.buffer = (*cinfo->mem->alloc_sarray)((j_common_ptr)cinfo, JPOOL_IMAGE, (JDIMENSION)rowbytes, 1);
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source->pub.buffer_height = 1;
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}
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METHODDEF(JDIMENSION)
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get_pixel_rows_png (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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{
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png_source_struct *source = (png_source_struct *)sinfo;
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png_read_row(source->png_ptr, source->pub.buffer[0], NULL);
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return 1;
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}
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METHODDEF(void)
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finish_input_png (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
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{
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png_source_struct *source = (png_source_struct *)sinfo;
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png_read_end(source->png_ptr, source->info_ptr);
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png_destroy_read_struct(&source->png_ptr, &source->info_ptr, NULL);
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}
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#endif
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