Based on this article written by Evan Wallace.
- rough glyph polygon rendering using odd-even rule
- glyph quadratic Bézier curve rendering
- grayscale antialiasing
- subpixel antialiasing
To see font subpixel antialiasing properly, zoom the page to get 1:1 canvas to display pixel mapping. For example, if your OS doesn't use any DPI scaling for your monitor, set the page zoom to 100%. If your OS is set to 200% DPI scale, zoom the page to 50%.
Otherwise, the text will be scaled.