#include #include #include "meh.h" struct png_t{ struct image img; FILE *f; png_structp png_ptr; png_infop info_ptr; png_infop end_info; int numpasses; }; static int ispng(FILE *f){ unsigned char buf[8]; if(fread(buf, 1, 8, f) != 8) return 0; return png_check_sig(buf, 8); } struct image *png_open(FILE *f){ struct png_t *p; rewind(f); if(!ispng(f)) return NULL; p = malloc(sizeof(struct png_t)); if((p->png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL)) == NULL){ free(p); return NULL; } if((p->info_ptr = png_create_info_struct(p->png_ptr)) == NULL){ png_destroy_read_struct(&p->png_ptr, (png_infopp)NULL, (png_infopp)NULL); free(p); return NULL; } if((p->end_info = png_create_info_struct(p->png_ptr)) == NULL){ png_destroy_read_struct(&p->png_ptr, &p->info_ptr, (png_infopp)NULL); free(p); return NULL; } if(setjmp(png_jmpbuf(p->png_ptr))){ png_destroy_read_struct(&p->png_ptr, &p->info_ptr, &p->end_info); free(p); return NULL; } p->f = f; rewind(f); png_init_io(p->png_ptr, f); png_read_info(p->png_ptr, p->info_ptr); p->img.bufwidth = png_get_image_width(p->png_ptr, p->info_ptr); p->img.bufheight = png_get_image_height(p->png_ptr, p->info_ptr); p->img.fmt = &libpng; return (struct image *)p; } int png_read(struct image *img){ unsigned int y; png_bytepp row_pointers; struct png_t *p = (struct png_t *)img; if(setjmp(png_jmpbuf(p->png_ptr))){ png_destroy_read_struct(&p->png_ptr, &p->info_ptr, &p->end_info); return 1; } { int color_type = png_get_color_type(p->png_ptr, p->info_ptr); int bit_depth = png_get_bit_depth(p->png_ptr, p->info_ptr); if (color_type == PNG_COLOR_TYPE_PALETTE) png_set_expand(p->png_ptr); if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) png_set_expand(p->png_ptr); if (png_get_valid(p->png_ptr, p->info_ptr, PNG_INFO_tRNS)) png_set_expand(p->png_ptr); if (bit_depth == 16) png_set_strip_16(p->png_ptr); if (color_type == PNG_COLOR_TYPE_GRAY || color_type == PNG_COLOR_TYPE_GRAY_ALPHA) png_set_gray_to_rgb(p->png_ptr); png_set_strip_alpha(p->png_ptr); if(png_get_interlace_type(p->png_ptr, p->info_ptr) == PNG_INTERLACE_ADAM7) p->numpasses = png_set_interlace_handling(p->png_ptr); else p->numpasses = 1; png_read_update_info(p->png_ptr, p->info_ptr); } row_pointers = (png_bytepp)malloc(img->bufheight * sizeof(png_bytep)); for(y = 0; y < img->bufheight; y++) row_pointers[y] = img->buf + y * img->bufwidth * 3; png_read_image(p->png_ptr, row_pointers); free(row_pointers); img->state |= LOADED | SLOWLOADED; return 0; } void png_close(struct image *img){ struct png_t *p = (struct png_t *)img; png_destroy_read_struct(&p->png_ptr, &p->info_ptr, &p->end_info); fclose(p->f); } struct imageformat libpng = { png_open, NULL, png_read, png_close };