I can't give a specific solution for processing but if you are ok with a generic answer you can do the following and then possibly integrate that with processing:
Chrome's text ability is currently poor (I believe a left-over from WebKit) not just with canvas but in general. This becomes especially visible when rotation is applied. The (backward) "ø
" you see is in fact the e
but due to the poor text engine and rounding errors the details melts together and it ends up looking like a Nordic char in this case.
A work-around is to draw the text you want to rotate to an off-screen canvas with no rotation applied, then use that canvas as an image that you draw to your main canvas to which rotation is applied.
This will produce a much better result and also perform better as normal image interpolation is used instead of the text engine.
An example can be:
/// draw text to off-screen canvas
osCtx.font = '12px arial';
osCtx.textBaseline = 'top';
osCtx.fillText(txt, 0, 0);
/// draw off-screen canvas rotated to main canvas
ctx.translate(w * 0.5, h * 0.5);
ctx.rotate(0.5);
ctx.drawImage(osCanvas, 0, 0);
Which will result in the same text looking like this instead:
versus drawn directly as text: