The PNGCrush Emscripten demo is available at https://github.com/gonfunko/CS-263/tree/master/Project/pngcrush-emscripten. To get the source, clone the root git repo and copy the pngcrush-emscripten folder into a directory being served by a web server.
The entire demo is functional as soon as it is being served. Navigate to index.html in a browser, and drag a PNG image into the drag region in the lower left corner. Alternatively, you can use the Upload an image button to choose a PNG using a standard file picker dialog. As soon as the image is uploaded, PNGCrush will be run on it, and the compressed image will be downloaded to your system.
If you’d like to rebuild the main PNGCrush JavaScript file, you can do so fairly easily. Start by following the instructions in Installation.
Then, copy the src directory to the same directory as your Emscripten installation directory (named emscripten), cd into src, and run the following commands:
The final command compiles the LLVM bitcode to JavaScript, includes the functions in the done.js file, runs at a high optimization level, disables the Closure compiler (necessary to prevent runtime issues) and writes out pngcrush.js. This file can be copied into the js directory to deploy it.