On Mon, Dec 5, 2011 at 5:29 PM, Dennis E. Hamilton <[email protected]> wrote: > Without looking, but based on how Eric described the effect, I believe it is > aliasing on the monitor if not elsewhere in the pipeline. Especially if it > shows a Moiré pattern. >
If it is a gradient, and it happens at high zooms, then this could be banding. http://en.wikipedia.org/wiki/Colour_banding -Rob > There are an amazing number of places in the rendering pipeline where > something could be off, especially if there is any intermediate resampling. > > It is a function of rasterization of the image. > > - Dennis > > PS: The funniest case for me is when I attempt to take pictures of my > computer LCD display with my digital camera. The LCD preview on the back of > the camera shows unbelievably bad Moiré (think of the number of times > resampling, especially down-sampling, is being done), but if I zoom into the > image on the camera's LCD display I find that the 10 Mpixel digital image is > often -- not always -- clean and without much aliasing, if any. (My manual > anti-aliasing procedure is to defocus the image slightly.) > > > -----Original Message----- > From: eric b [mailto:[email protected]] > Sent: Monday, December 05, 2011 09:57 > To: [email protected] > Subject: Re: [Code] strategy for "child works spaces" > > Hi, > > Le 5 déc. 11 à 18:51, Rory O'Farrell a écrit : > >> On Mon, 5 Dec 2011 18:40:14 +0100 >> eric b <[email protected]> wrote: >> <snip> >>> 2) Opening an .svg containing gradients, I played with the zoom, >>> until a big value, and the only strange issue I saw was sort of >>> spatial filtering, say spectral effect, like aliasing in the areas >>> containing the gradient. After some tries, the phenomen occurs >>> every times for some well defined zoom values (sorry if I'm not >>> clear). >> >> Do you mean that the continuous tone gradient resolves into dicrete >> tonal steps? >> > > Something lke that, yes. In applied optics (my job in the real life) > the name is "aliasing", but I'm unsure this is what we observe here. > > If you want to verify, I can provide a link to download Mac OS X > Intel build, either german, english or french (apologies, Windows is > not finished yet). > > > Regards, > Eric > > -- > qɔᴉɹə > Projet OOo4Kids : http://wiki.ooo4kids.org/index.php/Main_Page > L'association EducOOo : http://www.educoo.org > Blog : http://eric.bachard.org/news > > > > > >
