coco
125 lines
4.3 KiB
C++
125 lines
4.3 KiB
C++
// Copyright (C) 2011 Davis E. King (davis@dlib.net)
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// License: Boost Software License See LICENSE.txt for the full license.
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#ifndef DLIB_SAVE_PnG_CPPh_
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#define DLIB_SAVE_PnG_CPPh_
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// only do anything with this file if DLIB_PNG_SUPPORT is defined
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#ifdef DLIB_PNG_SUPPORT
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#include "save_png.h"
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#include <cstdio>
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#include <png.h>
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#include "../byte_orderer.h"
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namespace dlib
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{
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// Don't do anything when libpng calls us to tell us about an error. Just return to
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// our own code and throw an exception (at the long jump target).
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void png_reader_user_error_fn_silent(png_structp png_struct, png_const_charp )
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{
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longjmp(png_jmpbuf(png_struct),1);
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}
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void png_reader_user_warning_fn_silent(png_structp , png_const_charp )
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{
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}
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namespace impl
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{
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void impl_save_png (
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const std::string& file_name,
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std::vector<unsigned char*>& row_pointers,
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const long width,
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const png_type type,
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const int bit_depth
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)
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{
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FILE *fp;
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png_structp png_ptr;
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png_infop info_ptr;
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/* Open the file */
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fp = fopen(file_name.c_str(), "wb");
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if (fp == NULL)
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throw image_save_error("Unable to open " + file_name + " for writing.");
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/* Create and initialize the png_struct with the desired error handler
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* functions. If you want to use the default stderr and longjump method,
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* you can supply NULL for the last three parameters. We also check that
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* the library version is compatible with the one used at compile time,
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* in case we are using dynamically linked libraries. REQUIRED.
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*/
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png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, &png_reader_user_error_fn_silent, &png_reader_user_warning_fn_silent);
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if (png_ptr == NULL)
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{
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fclose(fp);
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throw image_save_error("Error while writing PNG file " + file_name);
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}
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/* Allocate/initialize the image information data. REQUIRED */
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info_ptr = png_create_info_struct(png_ptr);
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if (info_ptr == NULL)
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{
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fclose(fp);
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png_destroy_write_struct(&png_ptr, NULL);
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throw image_save_error("Error while writing PNG file " + file_name);
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}
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/* Set error handling. REQUIRED if you aren't supplying your own
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* error handling functions in the png_create_write_struct() call.
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*/
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if (setjmp(png_jmpbuf(png_ptr)))
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{
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/* If we get here, we had a problem writing the file */
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fclose(fp);
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png_destroy_write_struct(&png_ptr, &info_ptr);
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throw image_save_error("Error while writing PNG file " + file_name);
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}
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int color_type = 0;
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switch(type)
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{
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case png_type_rgb: color_type = PNG_COLOR_TYPE_RGB; break;
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case png_type_rgb_alpha: color_type = PNG_COLOR_TYPE_RGB_ALPHA; break;
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case png_type_gray: color_type = PNG_COLOR_TYPE_GRAY; break;
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default:
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{
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fclose(fp);
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png_destroy_write_struct(&png_ptr, &info_ptr);
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throw image_save_error("Invalid color type");
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}
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}
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/* Set up the output control if you are using standard C streams */
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png_init_io(png_ptr, fp);
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int png_transforms = PNG_TRANSFORM_IDENTITY;
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byte_orderer bo;
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if (bo.host_is_little_endian())
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png_transforms |= PNG_TRANSFORM_SWAP_ENDIAN;
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const long height = row_pointers.size();
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png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth, color_type, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
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png_set_rows(png_ptr, info_ptr, &row_pointers[0]);
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png_write_png(png_ptr, info_ptr, png_transforms, NULL);
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/* Clean up after the write, and free any memory allocated */
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png_destroy_write_struct(&png_ptr, &info_ptr);
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/* Close the file */
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fclose(fp);
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}
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}
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}
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#endif // DLIB_PNG_SUPPORT
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#endif // DLIB_SAVE_PnG_CPPh_
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