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+/*
+LodePNG Examples
+
+Copyright (c) 2005-2012 Lode Vandevenne
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+ 1. The origin of this software must not be misrepresented; you must not
+ claim that you wrote the original software. If you use this software
+ in a product, an acknowledgment in the product documentation would be
+ appreciated but is not required.
+
+ 2. Altered source versions must be plainly marked as such, and must not be
+ misrepresented as being the original software.
+
+ 3. This notice may not be removed or altered from any source
+ distribution.
+*/
+
+#include "lodepng.h"
+#include <iostream>
+
+/*
+This example converts a PNG file to a BMP file.
+NOTE: it overwrites the output file without warning if it exists!
+Give the PNG and the BMP file names as command line arguments.
+*/
+
+/*
+g++ lodepng.cpp example_png2bmp.cpp -Wall -Wextra -pedantic -ansi -lSDL -O3
+*/
+
+
+
+//Input image must be RGB buffer (3 bytes per pixel), but you can easily make it
+//support RGBA input and output by changing the inputChannels and/or outputChannels
+//in the function to 4.
+void encodeBMP(std::vector<unsigned char>& bmp, const unsigned char* image, int w, int h)
+{
+ //3 bytes per pixel used for both input and output.
+ int inputChannels = 3;
+ int outputChannels = 3;
+
+ //bytes 0-13
+ bmp.push_back('B'); bmp.push_back('M'); //0: bfType
+ bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); //2: bfSize; size not yet known for now, filled in later.
+ bmp.push_back(0); bmp.push_back(0); //6: bfReserved1
+ bmp.push_back(0); bmp.push_back(0); //8: bfReserved2
+ bmp.push_back(54 % 256); bmp.push_back(54 / 256); bmp.push_back(0); bmp.push_back(0); //10: bfOffBits (54 header bytes)
+
+ //bytes 14-53
+ bmp.push_back(40); bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); //14: biSize
+ bmp.push_back(w % 256); bmp.push_back(w / 256); bmp.push_back(0); bmp.push_back(0); //18: biWidth
+ bmp.push_back(h % 256); bmp.push_back(h / 256); bmp.push_back(0); bmp.push_back(0); //22: biHeight
+ bmp.push_back(1); bmp.push_back(0); //26: biPlanes
+ bmp.push_back(outputChannels * 8); bmp.push_back(0); //28: biBitCount
+ bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); //30: biCompression
+ bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); //34: biSizeImage
+ bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); //38: biXPelsPerMeter
+ bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); //42: biYPelsPerMeter
+ bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); //46: biClrUsed
+ bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); //50: biClrImportant
+
+ /*
+ Convert the input RGBRGBRGB pixel buffer to the BMP pixel buffer format. There are 3 differences with the input buffer:
+ -BMP stores the rows inversed, from bottom to top
+ -BMP stores the color channels in BGR instead of RGB order
+ -BMP requires each row to have a multiple of 4 bytes, so sometimes padding bytes are added between rows
+ */
+
+ int imagerowbytes = outputChannels * w;
+ imagerowbytes = imagerowbytes % 4 == 0 ? imagerowbytes : imagerowbytes + (4 - imagerowbytes % 4); //must be multiple of 4
+
+ for(int y = h - 1; y >= 0; y--) //the rows are stored inversed in bmp
+ {
+ int c = 0;
+ for(int x = 0; x < imagerowbytes; x++)
+ {
+ if(x < w * outputChannels)
+ {
+ int inc = c;
+ //Convert RGB(A) into BGR(A)
+ if(c == 0) inc = 2;
+ else if(c == 2) inc = 0;
+ bmp.push_back(image[inputChannels * (w * y + x / outputChannels) + inc]);
+ }
+ else bmp.push_back(0);
+ c++;
+ if(c >= outputChannels) c = 0;
+ }
+ }
+
+ // Fill in the size
+ bmp[2] = bmp.size() % 256;
+ bmp[3] = (bmp.size() / 256) % 256;
+ bmp[4] = (bmp.size() / 65536) % 256;
+ bmp[5] = bmp.size() / 16777216;
+}
+
+int main(int argc, char *argv[])
+{
+ if(argc < 3)
+ {
+ std::cout << "Please provice input PNG and output BMP file names" << std::endl;
+ return 0;
+ }
+ const char* infile = argv[1];
+ const char* outfile = argv[2];
+
+
+ std::vector<unsigned char> image; //the raw pixels
+ unsigned width, height;
+
+ unsigned error = lodepng::decode(image, width, height, infile, LCT_RGB, 8);
+
+ if(error)
+ {
+ std::cout << "error " << error << ": " << lodepng_error_text(error) << std::endl;
+ return 0;
+ }
+
+ std::vector<unsigned char> bmp;
+ encodeBMP(bmp, &image[0], width, height);
+
+ lodepng::save_file(bmp, outfile);
+}