Bug 697048

Summary:	Regression: missing drop shadow starting with 093bd18bd923644fcd25c507088c0ebc63b4c320
Product:	Ghostscript	Reporter:	Marcos H. Woehrmann <marcos.woehrmann>
Component:	Graphics Library	Assignee:	Ray Johnston <ray.johnston>
Status:	RESOLVED FIXED
Severity:	normal	CC:	robin.watts
Priority:	P4
Version:	master
Hardware:	PC
OS:	All
Customer:		Word Size:	---
Attachments:	testdrop3.txt testdrop5.pdf

Description Marcos H. Woehrmann 2016-08-15 11:17:32 UTC

Starting with 093bd18bd923644fcd25c507088c0ebc63b4c320 the attached PDF file is rendered without its drop shadow when converted to pkmraw.  Converting to ppmraw works as expected.

The command line I'm using for testing:

  bin/gs sDEVICE=pkmraw -o test.pkm -r300 ./testdrop.pdf

Comment 2 Robin Watts 2017-02-23 07:01:56 UTC

Created attachment 13421 [details]
testdrop3.txt

Greatly simplified file.

We start with a simple cyan background, then plot a black rectangle drawn on top of it, using Multiply blendmode, with an overprint mode of 1.

  gs -sDEVICE=ppmraw -o out.ppm -r72 testdrop3.pdf

shows the rectangle as expected.

  gs -sDEVICE=pkmraw -o out.pkm -r72 testdrop3.pdf

shows no markings from the rectangle.

Comment 3 Robin Watts 2017-02-24 10:18:48 UTC

Created attachment 13426 [details]
testdrop5.pdf

Better example file (silly typo fixed).

Comment 4 Robin Watts 2017-02-24 12:34:08 UTC

Fixed in:

commit af3c1d10726b2d932d951bf021193cbd5bcc734d
Author: Robin Watts <robin.watts@artifex.com>
Date:   Fri Feb 24 19:05:52 2017 +0000

    Bug 697048: Fix compatible overprint blend mode.

    Fix from Michael Vrhel.

    Compatible overprint is operating in subtractive color spaces, so
    a 'zero' component actually means 0xFF.