At the web page http://srufaculty.sru.edu/david.dailey/svg/composite.svg
Opera (9.6) and IE/ASV do things surprisingly similar. I had previously suspected not so much similarity would exist ever between complex filters such as feTurbulence with feComposite. The reading of the seed variable in feTurbulence appears to result in a nearly identical rendition. A notable exception is the example using operator arithmetic with a mask applied. The SMIL animation of baseFrequency (coincident with that of seed to provide a large basis for comparison) is quite different between these two SMIL supporting browsers. Let's turn off the SMIL and look at just the still frames: http://srufaculty.sru.edu/david.dailey/svg/composite2.svg Here we may now compare FF as well which supports those filters (Safari and Chrome are not there yet). The chroma in FF and IE are more similar, but the radius in FF and Opera are more similar. In Opera the interaction between the chroma of the mask and those of the image itself seem to be more pronounced. Which implementation is "correct"? The simpler "composite/arithmetic" examples may be contrasted in Photoshop by superimposing the images under a "difference" filter - subtracting one image from another. Two identical images subtracted from one another leave a monochrome black rectangle. In http://srufaculty.sru.edu/david.dailey/svg/CompositeDiff.jpg We may see the differences between the three renderings. Opera and IE are almost (but not quite) identical. FF is the odd one out. If one rescales the images a wee bit (by shrinking the Opera image while overlaying) one can approach a blacker rectangle, implying that most of the differences observed are due to slight differences in the size of the drawing space. As we begin to talk about cross-browser standards for passing or not passing tests and benchmarks, I have been skeptical that specs will ever nail things down precisely enough to allow bitwise comparison of output. This little experiment ended up closer than I expected it would, but still supports the basic premise that exactness of output may never be pixel perfect across browsers. On the other hand, it seems as though the wild divergence of the case with the mask applied over the composite filter is a bit more divergent than I would have expected, and particularly when the animation is applied. FWIW, the effect in Opera is what I was trying for, though I'm not confident that that's what it should have been. (Ultimately I wanted a fractal shape - not an oval - to be filled with fractal-looking chroma, wiggling cloud-like over time) cheers David [Non-text portions of this message have been removed] ------------------------------------ ----- To unsubscribe send a message to: [EMAIL PROTECTED] -or- visit http://groups.yahoo.com/group/svg-developers and click "edit my membership" ----Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/svg-developers/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/svg-developers/join (Yahoo! ID required) <*> To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
