The alpha channel example, Example 30 e.g. x30c, generates Postscript files that do not display the transparency effect on my OS X machine. The first page has the colored boxes but without transparency; also, there is no black border.
The second page shows only a single large red box with no alpha and with a black border only at the top and right. Also, there is a black hairline near the bottom of the red square which, when dissected with a graphics program, reveals that the big red box actually is two red boxes and the black hairline is a small gap between them. (Small gaps between abutting graphics shows up in other places such as in surface plots, so this might not be unique to this example.) The black hairline notwithstanding, dissection in a graphics program shows that the smaller colored boxes are in fact present but completely obscured due to lack of transparency in the red box which lies in front of them. The two pages of this example display the same on either Adobe Reader 8.1.2 or PDF viewers based on Apple's PDFkit such as Preview and Skim. However, I notice that Adobe Reader will not read Postscript files (has that always been the case?) and I converted the Postscript files to PDF using Preview, Apple's reader app; there could be a problem with the conversion that caused the Adobe Reader results to be the same. Safari 3.1.1 and Firefox 3.0 display the SVG files also without alpha and with a different set of other artifacts. The PNG file displays with no alpha and pastel (that is, faded, or reduced saturation) box colors from page 1. (Page 2 is not generated or does not display when I open the file.) The amount and nature (brightness) of the fading depends on what program I use to view the file. The JPEG file displays proper colors and borders for page 1 but no alpha. GIF looks same as JPEG. Short version: no alpha to be seen anywhere on my machine. Jerry ------------------------------------------------------------------------- Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 _______________________________________________ Plplot-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/plplot-devel
