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98 lines
3.0 KiB
98 lines
3.0 KiB
/*- pngtopng |
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* |
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* COPYRIGHT: Written by John Cunningham Bowler, 2011, 2017. |
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* To the extent possible under law, the author has waived all copyright and |
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* related or neighboring rights to this work. This work is published from: |
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* United States. |
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* |
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* Last changed in libpng 1.6.29 [March 16, 2017] |
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* |
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* Read a PNG and write it out in a fixed format, using the 'simplified API' |
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* that was introduced in libpng-1.6.0. |
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* |
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* This sample code is just the code from the top of 'example.c' with some error |
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* handling added. See example.c for more comments. |
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*/ |
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#include <stddef.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include <stdio.h> |
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/* Normally use <png.h> here to get the installed libpng, but this is done to |
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* ensure the code picks up the local libpng implementation: |
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*/ |
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#include "../../png.h" |
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#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) && \ |
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defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) |
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int main(int argc, const char **argv) |
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{ |
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int result = 1; |
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if (argc == 3) |
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{ |
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png_image image; |
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/* Only the image structure version number needs to be set. */ |
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memset(&image, 0, sizeof image); |
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image.version = PNG_IMAGE_VERSION; |
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if (png_image_begin_read_from_file(&image, argv[1])) |
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{ |
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png_bytep buffer; |
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/* Change this to try different formats! If you set a colormap format |
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* then you must also supply a colormap below. |
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*/ |
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image.format = PNG_FORMAT_RGBA; |
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buffer = malloc(PNG_IMAGE_SIZE(image)); |
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if (buffer != NULL) |
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{ |
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if (png_image_finish_read(&image, NULL/*background*/, buffer, |
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0/*row_stride*/, NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP */)) |
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{ |
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if (png_image_write_to_file(&image, argv[2], |
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0/*convert_to_8bit*/, buffer, 0/*row_stride*/, |
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NULL/*colormap*/)) |
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result = 0; |
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else |
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fprintf(stderr, "pngtopng: write %s: %s\n", argv[2], |
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image.message); |
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} |
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else |
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fprintf(stderr, "pngtopng: read %s: %s\n", argv[1], |
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image.message); |
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free(buffer); |
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} |
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else |
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{ |
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fprintf(stderr, "pngtopng: out of memory: %lu bytes\n", |
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(unsigned long)PNG_IMAGE_SIZE(image)); |
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/* This is the only place where a 'free' is required; libpng does |
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* the cleanup on error and success, but in this case we couldn't |
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* complete the read because of running out of memory and so libpng |
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* has not got to the point where it can do cleanup. |
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*/ |
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png_image_free(&image); |
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} |
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} |
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else |
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/* Failed to read the first argument: */ |
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fprintf(stderr, "pngtopng: %s: %s\n", argv[1], image.message); |
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} |
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else |
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/* Wrong number of arguments */ |
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fprintf(stderr, "pngtopng: usage: pngtopng input-file output-file\n"); |
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return result; |
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} |
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#endif /* READ && WRITE */
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