Bug 689439

Summary: Alpha type SMask incorrectly displayed
Product: Ghostscript Reporter: Adrian Johnson <ajohnson>
Component: PDF InterpreterAssignee: Michael Vrhel <michael.vrhel>
Status: RESOLVED FIXED    
Severity: normal Keywords: bountiable
Priority: P4    
Version: 8.60   
Hardware: PC   
OS: Linux   
Customer: Word Size: ---
Attachments: mask-alpha-pdf-argb32-out.pdf

Description Adrian Johnson 2007-09-09 06:13:19 UTC 
The attached file was displayed with gs -sDEVICE=x11
mask-alpha-pdf-argb32-out.pdf. The file does not display correctly in
Ghostscript 8.60. 

The file draws a triangle and rectangle in a transparency group with an Alpha
type SMask consisting of a circle with the RGBA (0.4, 0.4, 0.4, 0.8) and the
background with RGBA (0.8, 0.8, 0.8, 0.4).

Adobe Reader 8.1.0 on Windows XP displays the file correctly with area inside
the circle drawn with alpha=0.8 mask and the area outside the circle drawn with
alpha = 0.4 mask.

Using Ghostscript 8.60 the area inside the circle is drawn with what appears to
be the alpha=0.4 mask and the area outside the circle drawn with alpha=0.8. It
looks like Ghostscript is creating the mask from the colors instead of the alpha.

Adobe Reader 7 for Linux also displays the file incorrectly.
Comment 1 Adrian Johnson 2007-09-09 06:13:59 UTC 
Created attachment 3354 [details]
mask-alpha-pdf-argb32-out.pdf
Comment 2 Ray Johnston 2007-09-18 09:44:14 UTC 
Problem in transparency somewhat related to 689438
Comment 3 Ray Johnston 2007-12-17 12:08:39 UTC 
Reassigning to new owner
Comment 4 Michael Vrhel 2010-12-02 18:30:00 UTC 
This was fixed when we fixed alpha blending for the pdf 1.7 fts test files.