1400663 - No subpixel AA when using paint-order

Status: UNCONFIRMED

(Core :: Graphics: Text, defect, P3)

Description

[Philipp Pief]

Attachment: Windows default settings (DW)

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:56.0) Gecko/20100101 Firefox/56.0
Build ID: 20170914024831

Steps to reproduce:

1. Go to https://bl.ocks.org/Herst/cea785948891831cee238861735492d0?x=393.394&y=154.369&k=0.369&fontSize=50&strokeWidth=7&fontFamily=sans-serif a demo page which compares using paint-order to drawing a text twice.

2. See that in Example 1 and 2 are in principle doing the same so the result should look the same but this isn't the case. Most notably greyscale anti-aliasing is used in Example 2, the one using SVGs paint-order so the stroke is drawn behind the fill (as opposed to Example 1 which simply draws text elements with identical content but one for the stroke and the other for the fill).

Comment 1

[Robert Longson [:longsonr]]

I suspect that's just an artifact of where exactly you happen to draw the text.

Comment 2

[Philipp Pief]

Attachment: fxLin.png

Can't reproduce on my Linux Desktop BTW.

Comment 3

[Philipp Pief]

> I suspect that's just an artifact of where exactly you happen to draw the text.

No, as can be seen from the screenshots from bug 1427220 it even happens if you try to place the <svg:text>s on top of each other.

The screenshots of bug 1427220 also shows that the issue appears on Windows but not Linux. On Linux I am always getting greyscale antialiasing and in Google Chrome there is always subpixel AA.