Re: [Gimp-developer] Re: GIMP and multiple processors
Hi, Daniel Egger [EMAIL PROTECTED] writes: I just played around with the blend tool on a 100x100px image and looked very closely for any artifacts with and without supersampling. The result was that I couldn't produce any visible aliasing effects no matter how hard I try other than by using a sawtooth repeat pattern. That seems like a *huge* price to pay for something that can be easily done by accident. Sorry, but I don't see your point. It has been show that supersampling makes sense for some corner cases. It is off by default and users can activate it in case they run into one of the corner cases. Of course it could be faster but where's your problem? Sven ___ Gimp-developer mailing list Gimp-developer@lists.xcf.berkeley.edu http://lists.xcf.berkeley.edu/mailman/listinfo/gimp-developer
Re: [Gimp-developer] Re: GIMP and multiple processors
On 02.03.2005, at 13:29, Sven Neumann wrote: Sorry, but I don't see your point. It has been show that supersampling makes sense for some corner cases. It is off by default and users can activate it in case they run into one of the corner cases. Of course it could be faster but where's your problem? No problem on this side of the wire other then that is feature is counterintuitive, slow, undocumented and pretty much useless for the blend tool except for deliberate cases. I'm trying to figure out whether this (NB: the generic supersampling code) is something worth improving and if it is what an adequate interface would be. Servus, Daniel PGP.sig Description: This is a digitally signed message part
Re: [Gimp-developer] Re: GIMP and multiple processors
Hi, Daniel Egger [EMAIL PROTECTED] writes: No problem on this side of the wire other then that is feature is counterintuitive, slow, undocumented and pretty much useless for the blend tool except for deliberate cases. I agree that it is slow, but it is certainly not counterintuitive, it is documented and it is useful. The fact that it is not generally useful is reasonably reflected by the fact that it is off by default. Sven ___ Gimp-developer mailing list Gimp-developer@lists.xcf.berkeley.edu http://lists.xcf.berkeley.edu/mailman/listinfo/gimp-developer
Re: [Gimp-developer] Re: GIMP and multiple processors
On 01.03.2005, at 16:42, GSR - FR wrote: GSR (?) already gave such an example. It might be worth considering only supersampling when the end of a segment is a different color than the start of the next one. Supersampling is to avoid aliasing, which is not caused only by those discontinuities but high frequency data (IIRC abrupt change is like infinite frequency). You can have aliasing with a square wave (segments that do not match) but also with a sine wave (segments that match). Right. But where in reality can this happen using a gradient blend? I just played around with the blend tool on a 100x100px image and looked very closely for any artifacts with and without supersampling. The result was that I couldn't produce any visible aliasing effects no matter how hard I try other than by using a sawtooth repeat pattern. That seems like a *huge* price to pay for something that can be easily done by accident. What does the commercial counterpart offer here? Servus, Daniel PGP.sig Description: This is a digitally signed message part
Re: [Gimp-developer] Re: GIMP and multiple processors
On Tue, 2005-03-01 at 22:48 +0100, Daniel Egger wrote: On 01.03.2005, at 16:42, GSR - FR wrote: GSR (?) already gave such an example. It might be worth considering only supersampling when the end of a segment is a different color than the start of the next one. Supersampling is to avoid aliasing, which is not caused only by those discontinuities but high frequency data (IIRC abrupt change is like infinite frequency). You can have aliasing with a square wave (segments that do not match) but also with a sine wave (segments that match). Right. But where in reality can this happen using a gradient blend? I just played around with the blend tool on a 100x100px image and looked very closely for any artifacts with and without supersampling. The result was that I couldn't produce any visible aliasing effects no matter how hard I try other than by using a sawtooth repeat pattern. That seems like a *huge* price to pay for something that can be easily done by accident. What does the commercial counterpart offer here? Photoshop does not do antialiasing. It also does not offer as many gradient types that are likely to need it (for example spiral). It ought to be easy enough to detect when antialiasing will be needed and automagically turn it on. I havnt looked at the supersampling code yet, but I think it might be much faster to do the supersampling in a second pass since such a small percentage of pixels actually need it. Jay Cox [EMAIL PROTECTED] ___ Gimp-developer mailing list Gimp-developer@lists.xcf.berkeley.edu http://lists.xcf.berkeley.edu/mailman/listinfo/gimp-developer
