/* heatmap - High performance heatmap creation in C. * * The MIT License (MIT) * * Copyright (c) 2013 Lucas Beyer * * Permission is hereby granted, free of charge, to any person obtaining a copy of * this software and associated documentation files (the "Software"), to deal in * the Software without restriction, including without limitation the rights to * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of * the Software, and to permit persons to whom the Software is furnished to do so, * subject to the following conditions: * * The above copyright notice and this permission notice shall be included in all * copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ #include #include #include #include "lodepng.h" #include "heatmap.h" int main() { static const size_t w = 256, h = 512, npoints = 1000; unsigned char image[256*512*4]; unsigned i; /* Create the heatmap object with the given dimensions (in pixel). */ heatmap_t* hm = heatmap_new(w, h); srand(time(NULL)); /* Add a bunch of random points to the heatmap now. */ for(i = 0 ; i < npoints ; ++i) { /* Fake a normal distribution. */ unsigned x = rand() % w/3 + rand() % w/3 + rand() % w/3; unsigned y = rand() % h/3 + rand() % h/3 + rand() % h/3; heatmap_add_point(hm, x, y); } /* This creates an image out of the heatmap. * `image` now contains the image data in 32-bit RGBA. */ heatmap_render_default_to(hm, image); /* Now that we've got a finished heatmap picture, * we don't need the map anymore. */ heatmap_free(hm); /* Finally, we use the fantastic lodepng library to save it as an image. */ { unsigned error = lodepng_encode32_file("heatmap.png", image, w, h); if(error) fprintf(stderr, "Error (%u) creating PNG file: %s\n", error, lodepng_error_text(error)); } return 0; }