I was intrigued by feDisplacement, but I cannot seem to control (or figure out
how to control) the direction of the displacement.
Yes, I've had trouble controlling the thing precisely. The little experiments
with the checkerboard, are an attempt to calibrate those effects, here's
another experiment:
http://srufaculty.sru.edu/david.dailey/svg/later/displace7.svg in which you can
see the precise degree of effect as animated. FF4 Opera and ASV all do it I
think.
Here's one of the reasons I wanted to do it -- if one takes a jigsaw puzzle and
wishes to scramble the N pieces (sort of as in
http://srufaculty.sru.edu/david.dailey/svg/clips2.svg only scrambled) then the
repositioning of the images using clipPath will require N copies of the image
to be loaded, I suppose into RAM. For a 1000 piece puzzle that's going to be
expensive. Using a bitblt approach as in canvas one could segment those
memory footprints into much smaller units. and ultimately not consume much more
than the original size of the bitmap, but then the jigsaw pieces aren't objects
and its not easy to carve them into clipPaths and it's not easy to drag and
drop them as one does with SVG objects. So, I was interested in using an
underlying distortion map (created through script) to displace chunks of
imagery by fixed amounts. I couldn't get it to be as precise as I needed
though, and was tempted to complain about it, but could't quite figure out if
it was me or the filter that was at fault.
feOffset as seen here
http://srufaculty.sru.edu/david.dailey/svg/later/offsets7.svg works well in FF
but not at all quickly in Opera or ASV. It was the other thing I considered. If
the speed found in FF could be expected then it might solve my problem, but not
likely yours which requires more gradual and less discrete displacements.
cheers
David
- Original Message -
From: patrickdengler
To: svg-developers@yahoogroups.com
Sent: Sunday, February 20, 2011 5:52 PM
Subject: [svg-developers] Re: Filter Help
Wow! Thanks for the immediate follow up.
I've toyed with each of these, especially I was intrigued by feDisplacement,
but I cannot seem to control (or figure out how to control) the direction of
the displacement.
filter id=imageFilter
feDisplacementMap scale=25
yChannelSelector=B
xChannelSelector=R
in=SourceGraphic /
/filter
This does a pretty good job (or at least a start). I really want that boing
stretch look in whatever dx/dy direction.
[Non-text portions of this message have been removed]
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