[haiku-bugs] Re: [Haiku] #10214: WebPositive: border-radius make border color overwrite background.
- From: "pulkomandy" <trac@xxxxxxxxxxxx>
- Date: Wed, 05 Mar 2014 14:38:31 -0000
#10214: WebPositive: border-radius make border color overwrite background.
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Reporter: dsjonny | Owner: pulkomandy
Type: bug | Status: assigned
Priority: normal | Milestone: R1
Component: Applications/WebPositive | Version: R1/Development
Resolution: | Keywords:
Blocked By: | Blocking: 10311, 10319
Has a Patch: 0 | Platform: All
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Comment (by pulkomandy):
Problem identified, I think.
When the border is only 1 pixel big, it is drawn using line drawing
primitives. When it is bigger, it is drawn as a BShape made of 2 parts:
* An "outside" polygon that marks the outside limit of the border
* An "inside" polygon that marks the inside limit (where the contents
starts)
The idea is that these should "cancel" each other, so the BShape is filled
with a hole in the middle, letting the contents shine through. There are
two ways to do this:
* Use the even/odd fill rule, or
* Use the "winding"/"non-zero" rule, and make sure the two polygons are in
opposite directions (one should be clockwise, and the other counter-
clockwise). This way the winding of the intersection part will be 0, not
1. Note that such a polygon would also work with the even/odd rule.
In Haiku, we don't have an API for using the even/odd rule. Unfortunately,
WebKit apparently expects us to use the first way.
I'll see if I can change this in WebKit. However, supporting both winding
rules in Haiku will be required at some later point, anyway. (they are
part of the canvas API).
--
Ticket URL: <https://dev.haiku-os.org/ticket/10214#comment:7>
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