From 8f9856b3869ca85018dacf2f79b8c3e2e9830d48 Mon Sep 17 00:00:00 2001
From: Jeremias Maerki <jeremias@apache.org>
Date: Mon, 20 Mar 2006 13:49:05 +0000
Subject: [PATCH] Certain filter combinations in PDF could lead to invalid
 PDFs. DecodeParams were not properly handled. Default filter for XMP metadata
 set to NullFilter as XMP metadata should always be embedded as clear-text so
 non-PDF-aware XMP processors can extract the metadata. Default filter for
 DCT/JPEG- and CCITT/TIFF-encoded images set to NullFilter because these two
 compression methods already do a good job. An additional flate filter (as was
 applied before due to the single default) helps a just little but also adds
 processing time. If anyone wants to squeeze every possible bit out of the PDF
 you can use the following in the user configuration:       <filterList
 type="tiff">         <value>flate</value>       </filterList>      
 <filterList type="jpeg">         <value>flate</value>       </filterList>

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@387213 13f79535-47bb-0310-9956-ffa450edef68
---
 .../org/apache/fop/pdf/PDFFilterList.java     | 30 +++++++++++++++----
 status.xml                                    |  4 +++
 2 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/src/java/org/apache/fop/pdf/PDFFilterList.java b/src/java/org/apache/fop/pdf/PDFFilterList.java
index 6ffda9da7..c26185b37 100644
--- a/src/java/org/apache/fop/pdf/PDFFilterList.java
+++ b/src/java/org/apache/fop/pdf/PDFFilterList.java
@@ -163,8 +163,19 @@ public class PDFFilterList {
             }
         }
         if (filterset == null || filterset.size() == 0) {
-            // built-in default to flate
-            addFilter(new FlateFilter());
+            if (METADATA_FILTER.equals(type)) {
+                //XMP metadata should not be embedded in clear-text
+                addFilter(new NullFilter());
+            } else if (JPEG_FILTER.equals(type)) {
+                //JPEG is already well compressed
+                addFilter(new NullFilter());
+            } else if (TIFF_FILTER.equals(type)) {
+                //CCITT-encoded images are already well compressed
+                addFilter(new NullFilter());
+            } else {
+                // built-in default to flate
+                addFilter(new FlateFilter());
+            }
         } else {
             for (int i = 0; i < filterset.size(); i++) {
                 String v = (String)filterset.get(i);
@@ -187,17 +198,24 @@ public class PDFFilterList {
             List parms = new java.util.ArrayList();
 
             // run the filters
+            int nonNullParams = 0;
             for (int count = 0; count < filters.size(); count++) {
                 PDFFilter filter = (PDFFilter)filters.get(count);
                 // place the names in our local vector in reverse order
-                names.add(0, filter.getName());
-                if (filter.getDecodeParms() != null) {
-                    parms.add(0, filter.getDecodeParms());
+                if (filter.getName().length() > 0) {
+                    names.add(0, filter.getName());
+                    if (filter.getDecodeParms() != null) {
+                        parms.add(0, filter.getDecodeParms());
+                        nonNullParams++;
+                    } else {
+                        parms.add(0, null);
+                    }
                 }
             }
 
             // now build up the filter entries for the dictionary
-            return buildFilterEntries(names) + buildDecodeParms(parms);
+            return buildFilterEntries(names) 
+                    + (nonNullParams > 0 ? buildDecodeParms(parms) : "");
         }
         return "";
 
diff --git a/status.xml b/status.xml
index 4e23f12c1..f36b6968b 100644
--- a/status.xml
+++ b/status.xml
@@ -27,6 +27,10 @@
 
   <changes>
     <release version="FOP Trunk">
+      <action context="Code" dev="JM" type="fix">
+        Bugfix: Certain filter combinations in PDF could lead to invalid PDFs. 
+        DecodeParams were not properly handled.
+      </action>
       <action context="Code" dev="JM" type="fix">
         Bugfix: CCITT Group 4 encoded TIFF images with multiple strips are now properly
         embedded in PDF files.
-- 
2.39.5