[gs-cvs] gs/lib

[Raph Levien]

Update of /cvs/ghostscript/gs/lib
In directory casper:/tmp/cvs-serv7310/lib

Modified Files:
	pdf_main.ps 
Log Message:
Fix: Improve accuracy of transparency detection logic. Fixes SF
bug #586595.


Index: pdf_main.ps
===================================================================
RCS file: /cvs/ghostscript/gs/lib/pdf_main.ps,v
retrieving revision 1.55
retrieving revision 1.56
diff -u -d -r1.55 -r1.56
--- pdf_main.ps	22 Aug 2002 07:12:28 -0000	1.55
+++ pdf_main.ps	28 Aug 2002 17:34:16 -0000	1.56
@@ -801,23 +801,21 @@
 % ------ Transparency support ------ %
 
 % Determine whether a page might invoke any transparency features:
-%	- Group in the page dictionary
-%	- Non-default ca, CA, or SMask in an ExtGState
-%	- Form XObject with Group
+%	- Non-default BM, ca, CA, or SMask in an ExtGState
 %	- Image XObject with SMask
-% ****** DO WE NEED TO LOOK IN RESOURCE DICTS OF OTHER CONTENT STREAMS? ******
+% Note: we deliberately don't check to see whether a Group is defined,
+% because Adobe Illustrator 10 (and possibly other applications) define
+% a page-level group whether transparency is actually used or not.
+% Ignoring the presence of Group is justified because, in the absence
+% of any other transparency features, they have no effect.
 /pageusestransparency {		% <pagedict> pageusestransparency <bool>
   PDFversion 1.4 lt NOTRANSPARENCY or {
     pop false
   } {
-    dup /Group known {
-      pop true
-    } {
-      false exch {
-	dup resourceusestransparency { pop not exit } if
-	/Parent knownoget not { exit } if
-      } loop
-    } ifelse
+    false exch {
+      dup resourceusestransparency { pop not exit } if
+      /Parent knownoget not { exit } if
+    } loop
   } ifelse
 } bind def
 % Check the Resources of a page or Form.
@@ -827,6 +825,9 @@
     dup /ExtGState knownoget {
       false exch {
 	exch pop oforce
+	dup /BM knownoget { dup /Normal ne exch /Compatible ne and
+	                    { pop not exit } if
+                          } if
 	dup /ca knownoget { 1 ne { pop not exit } if } if
 	dup /CA knownoget { 1 ne { pop not exit } if } if
 	dup /SMask knownoget { /None ne { pop not exit } if } if
@@ -838,7 +839,6 @@
 	exch pop oforce dup /Subtype get
 	dup /Image eq { 1 index /SMask known { pop pop not exit } if } if
 	/Form eq {
-	  dup /Group known { pop not exit } if
 	  resourceusestransparency { not exit } if
 	} {
 	  pop