Wow! That is very odd. Firefox and Chrome show the squares in the same locations.
Opera, which, along with IE/ASV, for years has had the most stable and complete implementation of filters, does not show the oddity, making me think it is an implementation problem. The last time I looked at Perlin noise (e.g., [1]), I didn't see anything that should cause those discontinuities. Safari doesn't seem to like SVG, as a general principle and, like IE9 shows a black rectangle. I haven't been able to test in ASV yet. That FF and Chrome and Inkscape would all behave the same way, suggest that they all just plugged in the same slightly flawed chunk of underlying source code. I would suggest submitting a bug report to Firefox and see what those folks think about the issue. Interestingly, it happens at all values of numOctaves. How did you find these funny numbers: 514, 1977, 2337, 4777, 8032, 9615 ? (They are not a sequence in the Encyclopedia of sequences [2] - I tried just on a whim.) Did you really try all 10,000 values of seed? A lot of times with things involving seeds, there is also a modulus, m, and if Euler's totient function of the seed and the modulus is other than m-1, then you get funky holes in the periodicity, but, from my experience, those holes are usually more numerous. Cheers David [1] http://webstaff.itn.liu.se/~stegu/TNM022-2005/perlinnoiselinks/perlin-noise- math-faq.html [2] http://oeis.org/ From: svg-developers@yahoogroups.com [mailto:svg-developers@yahoogroups.com] On Behalf Of Ryan Richards Sent: Thursday, April 25, 2013 5:30 AM To: svg-developers@yahoogroups.com Subject: [svg-developers] Seed 514 in feTurbulence causes squares Seeds 514, 1977, 2337, 4777, 8032, 9615 (only checked 0-10000) cause blank squares in feTurbulence in Firefox, Inkscape, and Batik. Is it the algorithm itself or the implementations? <svg version="1.1" width="338" height="488" xmlns="http://www.w3.org/2000/svg";> <defs> <filter id="Seed"> <feTurbulence type="turbulence" baseFrequency="0.1 0.1" numOctaves="5" seed="514"/> </filter> </defs> <path d="m0,0 h338 v488 h-338 v-488" filter="url(#Seed)"/> </svg> [Non-text portions of this message have been removed] ------------------------------------ ----- To unsubscribe send a message to: svg-developers-unsubscr...@yahoogroups.com -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: svg-developers-dig...@yahoogroups.com svg-developers-fullfeatu...@yahoogroups.com <*> To unsubscribe from this group, send an email to: svg-developers-unsubscr...@yahoogroups.com <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
