I have a test which renders an AttributedString with few chars replaced by a shape. I am rendering this using a TextLayout. I am also rendering the blackbox bounds and outline of the text layout.

I see a difference between Mustang b40 and the current build (b90) (in fact, the diff appears on b59d as well). The outline drawn on the current build (b90) is not as smoother as it is shown in b40. For some characters such as 'e', 'a', 'g' - the outline is actually drawn inside the textlayout in certain curved areas.

I have attached a screenshot comparing b40 and b90. On Tiger, the image looks same as Mustang-b40. Hence this is a regression introduced in Mustang. These differences become less apparent when I turn on AA. I reproduced it for 'Helvetica'. I do see some differences for Arial also but not as apparent as 'Helvetica'.

I have attached a sample test. Execute the sample test. You would see a string being rendered with shapes (blue), blackbox bounds(red) and Textlayout outline (green). If the green outline overlaps on blue text, the bug is reproduced.