png2ff.c (1996B)
1 /* See LICENSE file for copyright and license details. */ 2 #include <arpa/inet.h> 3 4 #include <errno.h> 5 #include <stdint.h> 6 #include <stdio.h> 7 #include <stdlib.h> 8 #include <string.h> 9 10 #include <png.h> 11 12 #include "util.h" 13 14 static void 15 png_err(png_struct *pngs, const char *msg) 16 { 17 (void)pngs; 18 die("libpng: %s", msg); 19 } 20 21 static void 22 png_setup_reader(png_struct **s, png_info **i, uint32_t *w, uint32_t *h) 23 { 24 *s = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, png_err, NULL); 25 *i = png_create_info_struct(*s); 26 27 if (!*s || !*i) { 28 die("Failed to initialize libpng"); 29 } 30 31 png_init_io(*s, stdin); 32 if (png_get_valid(*s, *i, PNG_INFO_tRNS)) { 33 png_set_tRNS_to_alpha(*s); 34 } 35 png_set_add_alpha(*s, 255*257, PNG_FILLER_AFTER); 36 png_set_expand_gray_1_2_4_to_8(*s); 37 png_set_gray_to_rgb(*s); 38 png_set_packing(*s); 39 png_read_png(*s, *i, PNG_TRANSFORM_PACKING | PNG_TRANSFORM_EXPAND, NULL); 40 *w = png_get_image_width(*s, *i); 41 *h = png_get_image_height(*s, *i); 42 } 43 44 static void 45 usage(void) 46 { 47 die("usage: %s", argv0); 48 } 49 50 int 51 main(int argc, char *argv[]) 52 { 53 png_struct *pngs; 54 png_info *pngi; 55 uint32_t width, height, rowlen, r, i; 56 uint16_t *row; 57 uint8_t **pngrows; 58 59 /* arguments */ 60 argv0 = argv[0], argc--, argv++; 61 62 if (argc) { 63 usage(); 64 } 65 66 /* prepare */ 67 png_setup_reader(&pngs, &pngi, &width, &height); 68 row = ereallocarray(NULL, width, (sizeof("RGBA") - 1) * sizeof(uint16_t)); 69 rowlen = width * (sizeof("RGBA") - 1); 70 pngrows = png_get_rows(pngs, pngi); 71 72 /* write data */ 73 ff_write_header(width, height); 74 75 switch(png_get_bit_depth(pngs, pngi)) { 76 case 8: 77 for (r = 0; r < height; ++r) { 78 for (i = 0; i < rowlen; i++) { 79 row[i] = htons(257 * pngrows[r][i]); 80 } 81 efwrite(row, sizeof(uint16_t), rowlen, stdout); 82 } 83 break; 84 case 16: 85 for (r = 0; r < height; ++r) { 86 efwrite(pngrows[r], sizeof(uint16_t), rowlen, stdout); 87 } 88 break; 89 default: 90 die("Invalid bit-depth"); 91 } 92 93 /* clean up */ 94 png_destroy_read_struct(&pngs, &pngi, NULL); 95 96 return fshut(stdout, "<stdout>"); 97 }