761326 - test_2d.path.arc.scale.1 assumes unrealistic 0.098 tolerance or luck

Status: RESOLVED FIXED

(Core :: Graphics: Canvas2D, defect)

Description

[Benoit Jacob [:bjacob] (mostly away)]

Attachment: fix tolerance in test_2d.path.arc.scale.1

This test is failing on Android (we're enabling canvas tests on Android in bug 759221).

The reason is that it's creating a 100x50 canvas, drawing a circle centered at (50, 25) with radius 56 and expects it to fully cover the whole canvas. We have

  sqrt(50^2 + 25^2) ~= 55.902

So it's assuming a drawing tolerance of roughly 56 - 55.902 == 0.098.

Drawing tolerances used in browsers are typically larger than that: we seem to use 0.3 on mobile and 0.1 on desktop, and IIUC Chrome uses 0.5.

See: http://mxr.mozilla.org/mozilla-central/ident?i=CAIRO_GSTATE_TOLERANCE_DEFAULT&filter=

This patch edits this test to work with tolerances <= 0.5 and be more explicit.

Please send it upstream.

Comment 1

[Benoit Jacob [:bjacob] (mostly away)]

http://hg.mozilla.org/integration/mozilla-inbound/rev/e158c9ebe4a2

Comment 2

[Matt Brubeck (:mbrubeck)]

Sorry, I backed this out on inbound along with bug 759221 because of failures in multiple media tests on desktop platforms:
https://hg.mozilla.org/integration/mozilla-inbound/rev/3b2b9defe6f4

Comment 3

[Benoit Jacob [:bjacob] (mostly away)]

http://hg.mozilla.org/integration/mozilla-inbound/rev/d71c9973b8ed

Comment 4

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/d71c9973b8ed