diff options
| author | Lode <lvandeve@gmail.com> | 2015-02-16 22:55:55 +0100 |
|---|---|---|
| committer | Lode <lvandeve@gmail.com> | 2015-02-16 22:55:55 +0100 |
| commit | bf2aa0a46fc8c1d398604cd384bc2c583774cc1f (patch) | |
| tree | 08a444bab7d70c828f158608a9a2849b86b133c1 /example_sdl.cpp | |
| parent | 9eaef3d1764f0e1e0234362824d30fc2df51af4d (diff) | |
move examples to examples directory
Diffstat (limited to 'example_sdl.cpp')
| -rw-r--r-- | example_sdl.cpp | 132 |
1 files changed, 0 insertions, 132 deletions
diff --git a/example_sdl.cpp b/example_sdl.cpp deleted file mode 100644 index 0c68ef5..0000000 --- a/example_sdl.cpp +++ /dev/null @@ -1,132 +0,0 @@ -/* -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; - } -} |
