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Canvas drawWindow with context.scale adds borders around some images

NEW
Unassigned

Status

()

Core
Canvas: 2D
P3
normal
9 years ago
7 years ago

People

(Reporter: dholbert, Unassigned)

Tracking

Trunk
x86
Linux
Points:
---
Dependency tree / graph
Bug Flags:
blocking1.9.1 -
wanted1.9.1 +

Firefox Tracking Flags

(Not tracked)

Details

Attachments

(2 attachments)

(Reporter)

Description

9 years ago
Created attachment 333270 [details]
screenshot 1: borders added around one QMO logo and Google logo.

Steps to Reproduce:
 1. Open these URLs in tabs:
      http://www.google.com/
      http://www.mozilla.org/projects/minefield/
      [anything else]
 2. Use Ctrl-Tab to bring up the new Tab-Switcher
 3. Examine the previews for google and the minefield startup page.

ACTUAL RESULTS:  
  Some images in the previews have borders added around them.  These aren't just JPEG artifacts, AFAICT.

EXPECTED RESULTS:
  No new borders should be added in the previews.

See screenshots for examples. (I've added red arrows to point to the borders.)

I'm testing using a fresh mozilla-central debug build from today.
(Reporter)

Comment 1

9 years ago
Created attachment 333272 [details]
screenshot 2: top-border added to other QMO logo

This screenshot shows that the added borders aren't always the same.  In this case, a top border was added around the Q-shaped QMO logo on the left. (This top border was not present in screenshot 1.)

Updated

9 years ago
Component: Tabbed Browser → Layout: Canvas
Product: Firefox → Core
QA Contact: tabbed.browser → layout.canvas
My guess is that what's happening is that the image is RGB24, with a solid white background.. but we're hitting the EXTEND_PAD failure here, so we're sampling outside of the image bounds and getting solid black (because we're doing RGB24) compositing.  This is kinda broken in a lot of ways, but I really don't know what the right fix should be.

Updated

9 years ago
Summary: Ctrl-Tab Preview adds borders around some images → Canvas drawWindow with context.scale adds borders around some images

Updated

9 years ago
Blocks: 436304
Flags: blocking1.9.1?
Yep.  This might be fixed by roc's work in bug 458487.
Flags: wanted1.9.1+
Flags: blocking1.9.1?
Flags: blocking1.9.1-
Priority: -- → P3
(In reply to comment #3)
> Yep.  This might be fixed by roc's work in bug 458487.

I'm still seeing the borders around the QMO logos (attachment 333272 [details]).
Currently we're not pixel-snapping when there's a scale in the context, so these fringes are sure to happen.
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