On Thu, Jan 17, 2008 at 07:20:29PM -0800, Alan Irwin wrote: > On 2008-01-17 19:27-0000 Andrew Ross wrote: > > >> [...]Andrew (Ross), do you confirm the above qualitative problem with the > >> png > >> result? > > > > Alan, I can confirm that I observe exactly the same behaviour with both > > debian oldstable and ubuntu gutsy (latest stable). > > >> [...]Anyhow, Andrew, the apparent non-linear transformation between > >> transparency > >> index (alpha channel) and transparency result for both jpeg and png results > >> from libgd is a mystery which I hope you will be able to solve. > > > > I'm currently equally perplexed. Hopefully we can come up with a simple > > test case to try out some ideas. > > Hi Andrew: > > As you know I don't have access to cairo at the moment. However, you do. > How does the first page of example 30 compare for transparency between png > and pngcairo? My impression is the png version looks okay. If it happens > that pngcairo has the same transparency interpretation as png for the first > page, but not the second, that might be an important clue about where the > trouble lies.
By eye page 1 looks fine, but page 2 for png shows the problem you describe. To me this suggests it is something to do with the cmap1 palette. This is also why I didn't notice any problems when I first implemented the changes to the gd driver. Andrew ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
