PDF export of PDF images: compress page stream if requested

compressStream() automatically takes care of
VCL_DEBUG_DISABLE_PDFCOMPRESSION, so this also simplifies code.

Change-Id: I7661123e6ba73f8f064ec0543a03e2ec15fd2468
Reviewed-on: https://gerrit.libreoffice.org/36415
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Jenkins <ci@libreoffice.org>
(cherry picked from commit 54a4121f2040bd11f3d6056767f2d7ad6c7745ac)

2 files changed, 17 insertions, 12 deletions

diff --git a/vcl/qa/cppunit/pdfexport/pdfexport.cxx b/vcl/qa/cppunit/pdfexport/pdfexport.cxx
index 76cad0f2a9af..36b5134bdaf3 100644
--- a/vcl/qa/cppunit/pdfexport/pdfexport.cxx
+++ b/vcl/qa/cppunit/pdfexport/pdfexport.cxx
@@ -481,10 +481,16 @@ void PdfExportTest::testTdf107089()
     // Make sure 'Hello' is part of the form object's stream.
     vcl::filter::PDFStreamElement* pStream = pForm->GetStream();
     CPPUNIT_ASSERT(pStream);
-    SvMemoryStream& rObjectStream = pStream->GetMemory();
+    SvMemoryStream aObjectStream;
+    ZCodec aZCodec;
+    aZCodec.BeginCompression();
+    pStream->GetMemory().Seek(0);
+    aZCodec.Decompress(pStream->GetMemory(), aObjectStream);
+    CPPUNIT_ASSERT(aZCodec.EndCompression());
+    aObjectStream.Seek(0);
     OString aHello("Hello");
-    auto pStart = static_cast<const char*>(rObjectStream.GetData());
-    const char* pEnd = pStart + rObjectStream.GetSize();
+    auto pStart = static_cast<const char*>(aObjectStream.GetData());
+    const char* pEnd = pStart + aObjectStream.GetSize();
     auto it = std::search(pStart, pEnd, aHello.getStr(), aHello.getStr() + aHello.getLength());
     // This failed, 'Hello' was part only a mixed compressed/uncompressed stream, i.e. garbage.
     CPPUNIT_ASSERT(it != pEnd);
diff --git a/vcl/source/gdi/pdfwriter_impl.cxx b/vcl/source/gdi/pdfwriter_impl.cxx
index 2c94de56c183..a6ced4d62952 100644
--- a/vcl/source/gdi/pdfwriter_impl.cxx
+++ b/vcl/source/gdi/pdfwriter_impl.cxx
@@ -12003,10 +12003,11 @@ void PDFWriterImpl::writeReferenceXObject(ReferenceXObjectEmit& rEmit)
         aLine.append(aSize.Height());
         aLine.append(" ]");
 
+        if (!g_bDebugDisableCompression)
+            aLine.append(" /Filter/FlateDecode");
         aLine.append(" /Length ");
 
-        sal_Int32 nLength = 0;
-        OStringBuffer aStream;
+        SvMemoryStream aStream;
         for (auto pContent : aContentStreams)
         {
             filter::PDFStreamElement* pPageStream = pContent->GetStream();
@@ -12035,21 +12036,19 @@ void PDFWriterImpl::writeReferenceXObject(ReferenceXObjectEmit& rEmit)
                     continue;
                 }
 
-                nLength += aMemoryStream.GetSize();
-                aStream.append(static_cast<const sal_Char*>(aMemoryStream.GetData()), aMemoryStream.GetSize());
+                aStream.WriteBytes(aMemoryStream.GetData(), aMemoryStream.GetSize());
             }
             else
-            {
-                nLength += rPageStream.GetSize();
-                aStream.append(static_cast<const sal_Char*>(rPageStream.GetData()), rPageStream.GetSize());
-            }
+                aStream.WriteBytes(rPageStream.GetData(), rPageStream.GetSize());
         }
 
+        compressStream(&aStream);
+        sal_Int32 nLength = aStream.Tell();
         aLine.append(nLength);
 
         aLine.append(">>\nstream\n");
         // Copy the original page streams to the form XObject stream.
-        aLine.append(aStream.makeStringAndClear());
+        aLine.append(static_cast<const sal_Char*>(aStream.GetData()), aStream.GetSize());
         aLine.append("\nendstream\nendobj\n\n");
         if (!updateObject(nWrappedFormObject))
             return;