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92 lines
3.2 KiB
C++
92 lines
3.2 KiB
C++
/*
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LodePNG Examples
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Copyright (c) 2005-2012 Lode Vandevenne
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source
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distribution.
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*/
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#include "lodepng.h"
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#include <iostream>
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/*
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3 ways to decode a PNG from a file to RGBA pixel data (and 2 in-memory ways).
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*/
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//g++ lodepng.cpp example_decode.cpp -ansi -pedantic -Wall -Wextra -O3
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//Example 1
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//Decode from disk to raw pixels with a single function call
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void decodeOneStep(const char* filename) {
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std::vector<unsigned char> image; //the raw pixels
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unsigned width, height;
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//decode
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unsigned error = lodepng::decode(image, width, height, filename);
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//if there's an error, display it
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if(error) std::cout << "decoder error " << error << ": " << lodepng_error_text(error) << std::endl;
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//the pixels are now in the vector "image", 4 bytes per pixel, ordered RGBARGBA..., use it as texture, draw it, ...
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}
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//Example 2
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//Load PNG file from disk to memory first, then decode to raw pixels in memory.
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void decodeTwoSteps(const char* filename) {
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std::vector<unsigned char> png;
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std::vector<unsigned char> image; //the raw pixels
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unsigned width, height;
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//load and decode
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unsigned error = lodepng::load_file(png, filename);
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if(!error) error = lodepng::decode(image, width, height, png);
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//if there's an error, display it
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if(error) std::cout << "decoder error " << error << ": " << lodepng_error_text(error) << std::endl;
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//the pixels are now in the vector "image", 4 bytes per pixel, ordered RGBARGBA..., use it as texture, draw it, ...
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}
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//Example 3
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//Load PNG file from disk using a State, normally needed for more advanced usage.
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void decodeWithState(const char* filename) {
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std::vector<unsigned char> png;
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std::vector<unsigned char> image; //the raw pixels
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unsigned width, height;
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lodepng::State state; //optionally customize this one
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unsigned error = lodepng::load_file(png, filename); //load the image file with given filename
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if(!error) error = lodepng::decode(image, width, height, state, png);
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//if there's an error, display it
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if(error) std::cout << "decoder error " << error << ": "<< lodepng_error_text(error) << std::endl;
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//the pixels are now in the vector "image", 4 bytes per pixel, ordered RGBARGBA..., use it as texture, draw it, ...
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//State state contains extra information about the PNG such as text chunks, ...
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}
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int main(int argc, char *argv[]) {
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const char* filename = argc > 1 ? argv[1] : "test.png";
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decodeOneStep(filename);
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}
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