feComposite arithmetic is broken with neg values
Bug #1044989 reported by
v1nce
This bug affects 1 person
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Inkscape |
Invalid
|
Undecided
|
Unassigned |
Bug Description
I try to make the following filter
|a - b|
so I use
max(a,b) <=> lighter(a,b) <= ok
min(a,b) <=> darker(a,b) <= ok
|a,b| should be equal to max - min
So i joined max and min using a composite|
I used a black to white gradient over grey
I expected to get a grey/black/grey gradient and I only get a full grey
I tried some other combination to see if I get what I'd expected
(x >0)
x 0 0 0 = ok
0 x 0 0 = ok
0 0 x 0 = ok
0 0 0 x = ok
eveytime a negative value comes into the game then things go wrong
0 1 -1 0 = ko
0 0 -1 1 = ko
0 -1 0 1 = ko
Inkscape 0.48.3.1 r 9886
Ubuntu 12.04
tags: | added: filters-svg |
summary: |
- blendmode composite arithmetic is broken with neg values + feComposite arithmetic is broken with neg values |
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Reproduced with Inkscape 0.48.3.1 on OS X 10.7.4
Not fully reproduced with 0.48+devel r11643 (see attached bitmap export)
I have yet to find an SVG renderer which would render the filter effect ("Max(a,b) - Min(a,b)") as shown in the "What's expected" sample in the file:
- Firefox 14, Chromium 23, Safari 6 fail completely to render any of the used filter effects.
- Opera 12 does better, but also fails to render the bottom one ("Max(a,b) - Min(a,b)").
- Squiggle (Batik 1.7, 1.8pre) does better, but differs from the claimed expected result, and from what Inkscape trunk renders.
-> needs further investigation as to what the correct rendering of the custom filter effect in SVG would look like.