Common points in SVG polygon and polyline do not coincide




6 years ago
4 years ago


(Reporter: duncan.loveday, Unassigned)



15 Branch
Windows 7

Firefox Tracking Flags

(Not tracked)



(2 attachments)



6 years ago
Created attachment 700708 [details]

User Agent: Mozilla/5.0 (Windows NT 6.1; rv:20.0) Gecko/20130105 Firefox/20.0
Build ID: 20130105030839

Steps to reproduce:

Load this test SVG. note the point (300,200) in present in both the polygon and polyline.

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "">
<svg xmlns="">
<polygon points="200,200 300,200" fill="none" stroke="#00ff00" stroke-width="20px"/>
<polyline points="300,100 300,200" fill="none" stroke="#ff0000" stroke-width="20px"/>

Actual results:

In the resulting image the polygon and polyline do not meet in the corner.

Expected results:

In the resulting image the polygon and polyline should meet in the corner.

Comment 1

6 years ago
Same behaviour in Fx 17.0.1 and a recent nightly.

Displayed as expected in IE9 and earlier versions of Firefox.
Could you get a regression range please Duncan?

type about:buildconfig in the address bar in the last good and subsequent first bad build and post the Built from link please.

or alternatively and perhaps more simply: is a handy tool that automates the regression-finding process (and prints out a link at the end, with the last-good and first-bad changesets built in).
Component: General → SVG

Comment 3

6 years ago
Also looks correct in chrome and opera.

Yes I'll try to get the range.

Comment 5

6 years ago
Likely Azure-Thebes bug, not SVG. Disabling HWA fixes the issue.


Suspected bug:
Bas Schouten — Bug 715768: Enable Azure-Thebes wrapper by default for D2D. r=jrmuizel
Blocks: 715768
Component: SVG → Graphics
Ever confirmed: true
Keywords: regression
Version: 17 Branch → 15 Branch

Comment 6

6 years ago
Created attachment 700758 [details]
screenshot FF21 Win 7

Anyway I got various results with HWA/Azure on/off, see my screenshot.

Comment 7

6 years ago
Bottom left matches what I see in IE9, opera, chrome

Comment 8

6 years ago
Possibly worth mentioning that it is the polygon that looks wrong. It seems to overshoot at *both ends*. Two polylines look right; two polygons cross; a polygon and a polyline make a T shape.
Bottom left of that screenshot is what I see on Mac, fwiw.

Comment 10

6 years ago
Can I work around this in any way by changing my web app code ?
Can you still reproduce the issue with latest version with clean new fresh profile without any addons and plugins?
Flags: needinfo?(duncan.loveday)

Comment 12

4 years ago
I'm seeing "bottom left" of the second attachment now using a nightly for 38.0a1 (2015-01-17) (Built from That's probably correct as the mid points of the two lines coincide.
Flags: needinfo?(duncan.loveday)

Comment 13

4 years ago
Chrome, Opera, IE10, Safari and Firefox all show the "bottom left" version. Happy days.
Thank you very much for checking.
If it's fixed or it looks so, I'm closing this bug as WORKSFORME.
Last Resolved: 4 years ago
Resolution: --- → WORKSFORME
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