Methods for reading a PNG file into an internal pixel buffer.
Uses a lot of memory, and is not suitable for embedded platforms.
In examples/convert.toit there is an experimental converter from PNG
to an icon format. Making input for this from SVG can be done with
resvg:
./target/release/resvg --shape-rendering optimizeSpeed --text-rendering optimizeSpeed --image-rendering optimizeSpeed input.svg output.png
This disables Skia anti-aliasing, which is buggy and messes up the colours.