1025696 - animation-fill-mode doesn't behave as expected when animating background-position

Status: RESOLVED INVALID

(Core :: CSS Parsing and Computation, defect)

Description

[temhawk]

Attachment: Image strip to be animated in test case 001

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:30.0) Gecko/20100101 Firefox/30.0 (Beta/Release)
Build ID: 20140605174243

Steps to reproduce:

I wrote some HTML & CSS to create an animation from an image strip that contains several "frames". While I succeeded in creating the animation itself, I wanted the last frame to remain visible at the end of the animation and this is what I'm having trouble with. It seems that "animation-fill-mode: forwards;" does not work as it should. (Please see the attached test case).


Actual results:

The first frame (i.e. no background-position offsets) was shown when the animation completed.


Expected results:

The last frame (i.e. "background-position: -6000px;") should have been shown when the animation completed.

Comment 1

[temhawk]

Attachment: Test case 001

Comment 2

[temhawk]

Argh, silly me. There's no bug. I didn't understand how it works. There are 30 frames but you have to use steps(29), and reduce the background-position offset by 1 frame's height worth of pixels.