| /*- pngtopng |
| * |
| * COPYRIGHT: Written by John Cunningham Bowler, 2011. |
| * To the extent possible under law, the author has waived all copyright and |
| * related or neighboring rights to this work. This work is published from: |
| * United States. |
| * |
| * Read a PNG and write it out in a fixed format, using the 'simplified API' |
| * that was introduced in libpng-1.6.0. |
| * |
| * This sample code is just the code from the top of 'example.c' with some error |
| * handling added. See example.c for more comments. |
| */ |
| #include <stddef.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <stdio.h> |
| |
| /* Normally use <png.h> here to get the installed libpng, but this is done to |
| * ensure the code picks up the local libpng implementation: |
| */ |
| #include "../../png.h" |
| #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) && \ |
| defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) |
| |
| int main(int argc, const char **argv) |
| { |
| int result = 1; |
| |
| if (argc == 3) |
| { |
| png_image image; |
| |
| /* Only the image structure version number needs to be set. */ |
| memset(&image, 0, sizeof image); |
| image.version = PNG_IMAGE_VERSION; |
| |
| if (png_image_begin_read_from_file(&image, argv[1])) |
| { |
| png_bytep buffer; |
| |
| /* Change this to try different formats! If you set a colormap format |
| * then you must also supply a colormap below. |
| */ |
| image.format = PNG_FORMAT_RGBA; |
| |
| buffer = malloc(PNG_IMAGE_SIZE(image)); |
| |
| if (buffer != NULL) |
| { |
| if (png_image_finish_read(&image, NULL/*background*/, buffer, |
| 0/*row_stride*/, NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP */)) |
| { |
| if (png_image_write_to_file(&image, argv[2], |
| 0/*convert_to_8bit*/, buffer, 0/*row_stride*/, |
| NULL/*colormap*/)) |
| result = 0; |
| |
| else |
| fprintf(stderr, "pngtopng: write %s: %s\n", argv[2], |
| image.message); |
| |
| free(buffer); |
| } |
| |
| else |
| { |
| fprintf(stderr, "pngtopng: read %s: %s\n", argv[1], |
| image.message); |
| |
| /* This is the only place where a 'free' is required; libpng does |
| * the cleanup on error and success, but in this case we couldn't |
| * complete the read because of running out of memory. |
| */ |
| png_image_free(&image); |
| } |
| } |
| |
| else |
| fprintf(stderr, "pngtopng: out of memory: %lu bytes\n", |
| (unsigned long)PNG_IMAGE_SIZE(image)); |
| } |
| |
| else |
| /* Failed to read the first argument: */ |
| fprintf(stderr, "pngtopng: %s: %s\n", argv[1], image.message); |
| } |
| |
| else |
| /* Wrong number of arguments */ |
| fprintf(stderr, "pngtopng: usage: pngtopng input-file output-file\n"); |
| |
| return result; |
| } |
| #endif /* READ && WRITE */ |