Bug 692353

Summary:	TIFFSEP always antialiases against full "black"
Product:	Ghostscript	Reporter:	Adam Augusta <roxton>
Component:	PDF Interpreter	Assignee:	Alex Cherepanov <alex>
Status:	RESOLVED WORKSFORME
Severity:	normal	CC:	roxton
Priority:	P4
Version:	master
Hardware:	Macintosh
OS:	MacOS X
Customer:		Word Size:	---
Attachments:	Simple 2-spot PDF 50% field spot output

Description Adam Augusta 2011-07-18 13:22:35 UTC

Created attachment 7684 [details]
Simple 2-spot PDF

If I'm interpreting these results correctly, TIFFSEP always seems to antialias against solid "black", even if the adjacent spot isn't solid.

In this example, Spot #1 is a field of 50%.  Spot #2 is a flower on top of it.

When rasterized (result.s0.tif), the field of black is at 50%, except the pixels coincident with the flower, where some of the pixels are actually darker than 50%.

This bug may be associated with Bug 687674 and possibly Bug 692303.

gs -sDEVICE=tiffsep -dBATCH -dSAFER -dNOPAUSE -dGraphicsAlphaBits=4 -dTextAlphaBits=4 -r72 -sOutputFile="result.tif" AntiAliasTest.pdf 

This was tested against the master (configured with --with-libiconv=no).

Comment 1 Adam Augusta 2011-07-18 13:23:16 UTC

Created attachment 7685 [details]
50% field spot output

Comment 2 Ken Sharp 2013-06-11 09:53:53 UTC

This appears to be fixed in current code, possibly as a result of fixing some of the other problems referenced above.