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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.
-*/
-
-//Compile command for Linux:
-//g++ lodepng.cpp example_sdl.cpp -lSDL -O3 -o showpng
-
-/*
-LodePNG SDL example
-This example displays a PNG with a checkerboard pattern to show tranparency.
-It requires the SDL library to compile and run.
-If multiple filenames are given to the command line, it shows all of them.
-Press any key to see next image, or esc to quit.
-*/
-
-#include "lodepng.h"
-
-#include <iostream>
-#include <SDL/SDL.h>
-
-int show(const std::string& caption, const unsigned char* rgba, unsigned w, unsigned h)
-{
- //avoid too large window size by downscaling large image
- unsigned jump = 1;
- if(w / 1024 >= jump) jump = w / 1024 + 1;
- if(h / 1024 >= jump) jump = h / 1024 + 1;
-
- //init SDL
- if(SDL_Init(SDL_INIT_VIDEO) < 0)
- {
- std::cout << "error, SDL video init failed" << std::endl;
- return 0;
- }
- SDL_Surface* scr = SDL_SetVideoMode(w / jump, h / jump, 32, SDL_HWSURFACE);
- if(!scr)
- {
- std::cout << "error, no SDL screen" << std::endl;
- return 0;
- }
- SDL_WM_SetCaption(caption.c_str(), NULL); //set window caption
-
- //plot the pixels of the PNG file
- for(unsigned y = 0; y + jump - 1 < h; y += jump)
- for(unsigned x = 0; x + jump - 1 < w; x += jump)
- {
- //get RGBA components
- Uint32 r = rgba[4 * y * w + 4 * x + 0]; //red
- Uint32 g = rgba[4 * y * w + 4 * x + 1]; //green
- Uint32 b = rgba[4 * y * w + 4 * x + 2]; //blue
- Uint32 a = rgba[4 * y * w + 4 * x + 3]; //alpha
-
- //make translucency visible by placing checkerboard pattern behind image
- int checkerColor = 191 + 64 * (((x / 16) % 2) == ((y / 16) % 2));
- r = (a * r + (255 - a) * checkerColor) / 255;
- g = (a * g + (255 - a) * checkerColor) / 255;
- b = (a * b + (255 - a) * checkerColor) / 255;
-
- //give the color value to the pixel of the screenbuffer
- Uint32* bufp;
- bufp = (Uint32 *)scr->pixels + (y * scr->pitch / 4) / jump + (x / jump);
- *bufp = 65536 * r + 256 * g + b;
- }
-
- //pause until you press escape and meanwhile redraw screen
- SDL_Event event;
- int done = 0;
- while(done == 0)
- {
- while(SDL_PollEvent(&event))
- {
- if(event.type == SDL_QUIT) done = 2;
- else if(SDL_GetKeyState(NULL)[SDLK_ESCAPE]) done = 2;
- else if(event.type == SDL_KEYDOWN) done = 1; //press any other key for next image
- }
- SDL_UpdateRect(scr, 0, 0, 0, 0); //redraw screen
- SDL_Delay(5); //pause 5 ms so it consumes less processing power
- }
-
- SDL_Quit();
- return done == 2 ? 1 : 0;
-}
-
-/*shows image with SDL. Returns 1 if user wants to fully quit, 0 if user wants to see next image.*/
-int showfile(const char* filename)
-{
- std::cout << "showing " << filename << std::endl;
-
- std::vector<unsigned char> buffer, image;
- lodepng::load_file(buffer, filename); //load the image file with given filename
- unsigned w, h;
- unsigned error = lodepng::decode(image, w, h, buffer); //decode the png
-
- //stop if there is an error
- if(error)
- {
- std::cout << "decoder error " << error << ": " << lodepng_error_text(error) << std::endl;
- return 0;
- }
-
- return show(filename, &image[0], w, h);
-}
-
-int main(int argc, char* argv[])
-{
- if(argc <= 1) std::cout << "Please enter PNG file name(s) to display" << std::endl;
-
- for(int i = 1; i < argc; i++)
- {
- if(showfile(argv[i])) return 0;
- }
-}