565812 - Reconsider fallback behavior when nsISMILType:Add fails

Status: RESOLVED DUPLICATE of bug 573716

(Core :: SVG, defect)

Description

[Daniel Holbert [:dholbert]]

Attachment: testcase 1

jwatt brought up in IRC the question of what our fallback behavior should be when nsISMILType::Add fails -- particularly when it's in the middle of an animation sandwich.

I'm attaching a testcase that tests a variety of situations, where an animation in the middle of an animation sandwich fails at adding for whatever reason. (either because it's got an invalid value -- the empty string in this case -- or because it's got a valid value that can't be added -- "none" in this case.[1])

In particular: Should we allow animations to affect the animation sandwich at all, if they depend on addition & their addition fails?  Right now, we let them affect the sandwich, but perhaps we should change that...

[1] NOTE: Opera seems to allow interpolation & addition with the value "none", and treats it as if it were "black".  This isn't strictly correct, IMHO -- "none" is transparent, so it's not really interpolatable with RGB values.  For this reason, Mozilla's implementation doesn't allow addition/interpolation with none.

Comment 1

[Daniel Holbert [:dholbert]]

Right now, Firefox shows a dark red color, on all rects in testcase 1, which means only the final animation is actually having a visible effect.

Chromium shows a pale greenish color on all rects, which means that all animations are having a visible effect, except:
 - the second row is a little darker, indicating that from="invalid" by="valid" has some sort of minor effect without breaking everything
 - the bottom-right rect is black, indicating that by="none" breaks animations that stack on top of it.

Opera has a light-green in the first rect, indicating that <from=invalid by=invalid> doesn't affect animations above or below it in the sandwich.  However, the rest of the rects are some shade of red, similar to Mozilla.

Comment 2

[Daniel Holbert [:dholbert]]

(In reply to comment #1)
> Chromium shows a pale greenish color on all rects, which means that all
> animations are having a visible effect, except:

s/all animations/all valid animations/

Comment 3

[Daniel Holbert [:dholbert]]

This behavior may be specified somewhere in SVG SMIL specs, too -- if it is, that's great.  I'm mostly filing this bug for investigation, since I'm not sure our behavior is optimal, and Gecko/Presto/Webkit seem to all have different behavior.