kripken/emscripten — pull request #2747 by Daft-Freak (2014-08-30 18:02:59+00:00)
Title: add api useful for handling HiDPI

With this you can do something like:
```
double ratio = emscripten_get_device_pixel_ratio();
emscripten_set_canvas_size(w * ratio, h * ratio);
emscripten_set_canvas_css_size(w, h);
```
to get HiDPI webgl.