Not sure why those files are now hard to download but here are the direct links. Probably nothing surprising to the developers except for the very odd-looking lines in David's zoomed plot. Jerry
http://idisk.mac.com/oscarruitt-Public/PDFkit%20screen%20shot.pdf http://idisk.mac.com/oscarruitt-Public/Adobe%20Reader%20screen% 20shot.pdf http://idisk.mac.com/oscarruitt-Public/David's%20plot%20antialiased.pdf http://idisk.mac.com/oscarruitt-Public/David's%20plot%20not% 20antialiased.pdf Jerry On Nov 18, 2008, at 1:41 PM, Jerry wrote: > > > Begin forwarded message: > > From: Jerry Bauck <[EMAIL PROTECTED]> > Date: November 18, 2008 1:40:20 PM MST > To: plplot_general <plplot-general@lists.sourceforge.net> > Subject: Fwd: [Plplot-general] peculiar "segmented" fills using shade > plots / plplot 5.8.0 & 5.9.0 > > > > Begin forwarded message: > > From: Jerry <[EMAIL PROTECTED]> > Date: November 18, 2008 1:11:07 AM MST > To: plplot_general <plplot-general@lists.sourceforge.net> > Subject: Re: [Plplot-general] peculiar "segmented" fills using shade > plots / plplot 5.8.0 & 5.9.0 > > > On Nov 14, 2008, at 7:06 PM, Hezekiah M. Carty wrote: > >> On Fri, Nov 14, 2008 at 7:59 PM, David Seery <[EMAIL PROTECTED]> wrote: >>> I would like to produce contour plots in which the contours are >>> filled >>> with a solid colour. Although the documentation implies that this is >>> not possible, I gather from reading the examples that it is achieved >>> by calling plpsty(0). Unfortunately, subsequent calls to plshades >>> produce weirdly segmented images, in which the solid fill is >>> broken up >>> with unwanted lines, like this: >>> >>> http://www.damtp.cam.ac.uk/user/djs61/figures.pdf >> >> This is, at least in part, due to the fact the the plshade functions >> in PLplot draw the filled contours as a series of polygons. >> Depending >> on the output device settings used and (in the case of SVG, PS and >> PDF >> output) the viewer used, you may see gaps between these individual >> polygons. You can see this in the PNG output for example 21 on the >> PLplot web site (see the middle image at the bottom of the page):: >> >> http://plplot.sourceforge.net/examples.php?demo=21 > > I have seen this phenomenon routinely when looking at Postscript or > PDF using Apple's PDFkit rendering. I have no idea if it shows up on > other platforms or file formats. Typically there is a hairline gap > between polygons which does _not_ scale when zoomed--the hairline > remains a hairline at all zoom levels. With a surface plot in which a > front surface made of many polygons hides a hidden surface, the front > surface actually appears translucent because of the many "cracks." > The first time I saw this I thought that PLplot had an alpha channel. > (This was before it _did_ have an alpha channel.) Here is a screen > shot (from Skim, which uses PDFkit) of Example 21 from my Mac's > screen--note that the red grid lines are visible behind the surface, > too. > > (Go to http://public.me.com/oscarruitt and open PDFkit screen > shot.pdf) > > > I have assumed in the past that this is a rounding bug in Apple's > rendering routine. However, since the cracks disappear when > antialiasing is turned off (as Hez noted earlier in this thread), it > seems that it is an artifact of the antialiasing. Indeed, one can > easily see where it comes from if each polygon is individually > rendered against the dark or differently-colored background without > regard to the adjoining polygons. The edge of each polygon is > smoothed with the background, forming the dark (or colored) edge. > Then the adjoining polygon is rendered the same way, making its own > dark edge. Then the two images are laid next to one another and the > two dark edges line up (maybe with one obscuring the other) and form > the dark crack. The reason that they don't appear on prints is that > either they are much smaller since printer resolution is much better > than screen resolution and/or printers don't use antialiasing. > > For comparison, this is a screen shot from Adobe Reader 8.1.2 (which > I rarely use because, well, just look at Preview or Skim.) The > problem is better but still noticeable. > > (Go to http://public.me.com/oscarruitt and open Adobe Reader screen > shot.pdf) > > > I believe that Adobe bypasses Apple's antialiasing routines in favor > of their own which are less aggressive. > > > I zoomed in on David's plot at http://www.damtp.cam.ac.uk/user/djs61/ > figures.pdf, specifically the lines to the left. I was surprised to > see that they have an unusual appearance: > > Antialiased: > (Go to http://public.me.com/oscarruitt and open David's plot > antialiased.pdf) > > Not antialiased: > (Go to http://public.me.com/oscarruitt and open David's plot no > antialiased.pdf) > > > Not sure what is going on here. Surely a line is represented > mathematically as a line and not a bunch of squiggles. > > Jerry > > > > ---------------------------------------------------------------------- > --- > This SF.Net email is sponsored by the Moblin Your Move Developer's > challenge > Build the coolest Linux based applications with Moblin SDK & win > great prizes > Grand prize is a trip for two to an Open Source event anywhere in > the world > http://moblin-contest.org/redirect.php?banner_id=100&url=/ > _______________________________________________ > Plplot-general mailing list > Plplot-general@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/plplot-general > ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Plplot-general mailing list Plplot-general@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-general
