Color rendering & transparency with metapost
Hi, I have some trouble using a gradient background (solid) with a transparent element : \startMPinclusions def test_shade (expr a, b) = pickup pencircle scaled 1mm ; color ca ; ca := \MPcolor{a} ; color cb ; cb := \MPcolor{b} ; color cc ; cc := \MPcolor{c} ; sh := define_linear_shade(origin shifted(0cm,.5*\overlayheight),origin,ca,cb) ; fill fullsquare xscaled \overlaywidth yscaled \overlayheight withshade sh; draw origin withcolor cc; draw origin shifted(0cm,-.25*\overlayheight) withcolor cc; enddef ; \stopMPinclusions \setupcolors[state=start] \definecolor[a][r=.57254902,g=.784313725,b=.917647059] \definecolor[b][white] \definecolor[c][darkred] \starttext \defineoverlay[bgoverlay][\uniqueMPgraphic{bg_top_shade}] \setupbackgrounds[page][background=bgoverlay] \startuniqueMPgraphic{bg_top_shade} test_shade(origin, origin shifted(0cm,1cm)); draw fullcircle scaled 10cm shifted (0cm,0.25*\overlayheight) withcolor transparent(1,0.5,white) withpen pencircle scaled 2cm; %%%%%%%% If you comment out the previous line the color rendering is definitelly different... \stopuniqueMPgraphic \input knuth \stoptext I have searched the ML without success, any idea ? Regards, Renaud
On Sat, Nov 1, 2008 at 1:38 AM, Renaud Aubin
This is my test. Where is the problem ? minimals-beta Linux luigicasa-laptop 2.6.24-21-generic #1 SMP Tue Oct 21 23:43:45 UTC 2008 i686 GNU/Linux This is LuaTeX, Version snapshot-0.30.2-2008102016, build unknown ConTeXt MtxRun | current version: 2008.10.31 13:58 -- luigi
Thank Luigi for your response, the problem is that the background color rendering isn't the same if you comment out or not the following line : draw fullcircle scaled 10cm shifted (0cm,0.25*\overlayheight) withcolor transparent(1,0.5,white) withpen pencircle scaled 2cm; After some experiments, the problem is solved ( hence not understood ???) using rgb=no in setupcolors... It's maybe a viewer-centric problem : I use acroread 8.1.2 under linux. Renaud luigi scarso a écrit :
On Sat, Nov 1, 2008 at 2:06 AM, Renaud Aubin
true
After some experiments, the problem is solved ( hence not understood ???) using rgb=no in setupcolors...
They seem differents again
It's maybe a viewer-centric problem : I use acroread 8.1.2 under linux.
no, I don't believe. Try to investigate with \pdfcompresslevel0 at the beginning -- luigi
participants (2)
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luigi scarso -
Renaud Aubin