1915286 - Undefined direction angle if we cannot find a tangent angle in ComputePointAtLength()

Status: RESOLVED FIXED

(Core :: CSS Transitions and Animations, defect)

Description

[Boris Chiou [:boris]]

Attachment: testcase

It seems we may use an undefined direction angle if the path is just a point. e.g. see the yellow triangle in https://codepen.io/anon/pen/PrLYNw?editors=1100.

Comment 1

[Boris Chiou [:boris]]

Attachment: testcase

See the yellow triangle. It should use 0deg (i.e. toward right).

Comment 2

[Boris Chiou [:boris]]

Attachment: Bug 1915286 - Use 0rad as the default value if the path length is zero.

When ths path length is zero, we may get (0, 0) as the tangent angle
from ComputePointAtLength(). Using (0, 0) to atan2() may get an
undefined result. We should avoid this, so use 0rad. This makes more
sense and match other browsers.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/6d8f66466c14
Use 0rad as the default value if the path length is zero. r=dholbert

Comment 4

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/47830 for changes under testing/web-platform/tests

Comment 5

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/6d8f66466c14

Comment 6

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR merged by moz-wptsync-bot