On Sat, Aug 10, 2013 at 1:07 AM, Glenn Maynard <gl...@zewt.org> wrote:
> On Fri, Aug 9, 2013 at 11:07 PM, Rik Cabanier <caban...@gmail.com> wrote: > >> >> Chrome seems ignore stroke widths that are smaller than 1 (which is >>>> reasonable). >>>> >>> >>> (That seems wrong to me--it should continue to draw based on pixel >>> coverage--but that's a separate issue...) >>> >> >> Is it? Obviously you can't draw less than a pixel, but the user did >> specify that he wants it too look black. >> > > strokeStyle = "black" doesn't mean "every pixel in the stroke should be > black". It's the color of the pen. If you draw over half of a pixel with > a black pen, you get 50% grey. > > It'd be one thing if Chrome didn't antialias at all, but if Chrome is > antialiasing a stroke with a lineWidth of 1.5, it doesn't make sense that > it's not antialiasing a stroke with a lineWidth of 0.75. I don't think > this is strictly specified; the only mention of anti-aliasing is an example > of how to do it (oversampling). > Chrome (well, Skia actually) uses a "hairline" mode for line widths < 1. It draws a line of width 1, and uses the width to modulate the alpha. I think the idea is to prevent blotchiness/unevenness caused by undersampling or missed coverage (Skia uses 16 samples of AA). Here's an example: hairline on the left, .2 width path on the right: http://jsfiddle.net/FWLZt/ Stephen > > This is tangental, though. Might want to start another thread if you want > to go over this more, or we'll derail this one... > Done. > > > -- > Glenn Maynard > >
