tdf#102928 PDF export: do recompress CMYK images

The export filter writes /DeviceRGB unconditionally, so for now don't
optimize CMYK image handling here. Though the added GraphicDescriptor
API allows supporting this natively in the export filter in the future.

(cherry picked from commit 70537c8295f1b0a0c58b061dfca6cbc9def0d65b)

Change-Id: I76b44b910948467aeb1f15e5ae765201d183c99d
Reviewed-on: https://gerrit.libreoffice.org/55378
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

4 files changed, 40 insertions, 6 deletions

diff --git a/include/vcl/graphicfilter.hxx b/include/vcl/graphicfilter.hxx
index 2c9ad85b96a0..d84ae3f0a9fa 100644
--- a/include/vcl/graphicfilter.hxx
+++ b/include/vcl/graphicfilter.hxx
@@ -142,6 +142,7 @@ class VCL_DLLPUBLIC GraphicDescriptor final
     sal_uInt16          nPlanes;
     GraphicFileFormat   nFormat;
     bool                bOwnStream;
+    sal_uInt8 mnNumberOfImageComponents;
 
     void                ImpConstruct();
 
@@ -208,6 +209,9 @@ public:
     /** @return bits/pixel or 0 **/
     sal_uInt16          GetBitsPerPixel() const { return nBitsPerPixel; }
 
+    /** @return number of color channels */
+    sal_uInt8 GetNumberOfImageComponents() const { return mnNumberOfImageComponents; }
+
     /** @return filter number that is needed by the GraphFilter to read this format */
     static OUString GetImportFormatShortName( GraphicFileFormat nFormat );
 };
diff --git a/vcl/qa/cppunit/jpeg/JpegReaderTest.cxx b/vcl/qa/cppunit/jpeg/JpegReaderTest.cxx
index 024316c9e739..3d427da1c323 100644
--- a/vcl/qa/cppunit/jpeg/JpegReaderTest.cxx
+++ b/vcl/qa/cppunit/jpeg/JpegReaderTest.cxx
@@ -22,7 +22,7 @@ class JpegReaderTest : public test::BootstrapFixtureBase
         return m_directories.getURLFromSrc(maDataUrl) + sFileName;
     }
 
-    Bitmap loadJPG(const OUString& aURL);
+    Graphic loadJPG(const OUString& aURL);
 
 public:
     JpegReaderTest() :
@@ -91,19 +91,30 @@ bool checkRect(Bitmap& rBitmap, int aLayerNumber, long nAreaHeight, long nAreaWi
     return true;
 }
 
-Bitmap JpegReaderTest::loadJPG(const OUString& aURL)
+int getNumberOfImageComponents(const Graphic& rGraphic)
+{
+    GfxLink aLink = rGraphic.GetLink();
+    SvMemoryStream aMemoryStream(const_cast<sal_uInt8*>(aLink.GetData()), aLink.GetDataSize(),
+                                 StreamMode::READ | StreamMode::WRITE);
+    GraphicDescriptor aDescriptor(aMemoryStream, nullptr);
+    CPPUNIT_ASSERT(aDescriptor.Detect(true));
+    return aDescriptor.GetNumberOfImageComponents();
+}
+
+Graphic JpegReaderTest::loadJPG(const OUString& aURL)
 {
     GraphicFilter& rFilter = GraphicFilter::GetGraphicFilter();
     Graphic aGraphic;
     SvFileStream aFileStream(aURL, StreamMode::READ);
     ErrCode bResult = rFilter.ImportGraphic(aGraphic, aURL, aFileStream);
     CPPUNIT_ASSERT_EQUAL(ERRCODE_NONE, bResult);
-    return aGraphic.GetBitmapEx().GetBitmap();
+    return aGraphic;
 }
 
 void JpegReaderTest::testReadRGB()
 {
-    Bitmap aBitmap = loadJPG(getFullUrl("JPEGTestRGB.jpeg"));
+    Graphic aGraphic = loadJPG(getFullUrl("JPEGTestRGB.jpeg"));
+    Bitmap aBitmap = aGraphic.GetBitmapEx().GetBitmap();
     Size aSize = aBitmap.GetSizePixel();
     CPPUNIT_ASSERT_EQUAL(12L, aSize.Width());
     CPPUNIT_ASSERT_EQUAL(12L, aSize.Height());
@@ -113,11 +124,14 @@ void JpegReaderTest::testReadRGB()
     CPPUNIT_ASSERT(checkRect(aBitmap, 1, 8, 8, Color(0xff, 0x00, 0x00), nMaxDelta));
     CPPUNIT_ASSERT(checkRect(aBitmap, 2, 8, 8, Color(0x00, 0xff, 0x00), nMaxDelta));
     CPPUNIT_ASSERT(checkRect(aBitmap, 3, 8, 8, Color(0x00, 0x00, 0xff), nMaxDelta));
+
+    CPPUNIT_ASSERT_EQUAL(3, getNumberOfImageComponents(aGraphic));
 }
 
 void JpegReaderTest::testReadGray()
 {
-    Bitmap aBitmap = loadJPG(getFullUrl("JPEGTestGray.jpeg"));
+    Graphic aGraphic = loadJPG(getFullUrl("JPEGTestGray.jpeg"));
+    Bitmap aBitmap = aGraphic.GetBitmapEx().GetBitmap();
     Size aSize = aBitmap.GetSizePixel();
     CPPUNIT_ASSERT_EQUAL(12L, aSize.Width());
     CPPUNIT_ASSERT_EQUAL(12L, aSize.Height());
@@ -129,11 +143,14 @@ void JpegReaderTest::testReadGray()
     CPPUNIT_ASSERT(checkRect(aBitmap, 1, 8, 8, Color(0x36, 0x36, 0x36), nMaxDelta));
     CPPUNIT_ASSERT(checkRect(aBitmap, 2, 8, 8, Color(0xb6, 0xb6, 0xb6), nMaxDelta));
     CPPUNIT_ASSERT(checkRect(aBitmap, 3, 8, 8, Color(0x12, 0x12, 0x12), nMaxDelta));
+
+    CPPUNIT_ASSERT_EQUAL(1, getNumberOfImageComponents(aGraphic));
 }
 
 void JpegReaderTest::testReadCMYK()
 {
-    Bitmap aBitmap = loadJPG(getFullUrl("JPEGTestCMYK.jpeg"));
+    Graphic aGraphic = loadJPG(getFullUrl("JPEGTestCMYK.jpeg"));
+    Bitmap aBitmap = aGraphic.GetBitmapEx().GetBitmap();
     Size aSize = aBitmap.GetSizePixel();
     CPPUNIT_ASSERT_EQUAL(12L, aSize.Width());
     CPPUNIT_ASSERT_EQUAL(12L, aSize.Height());
@@ -143,6 +160,8 @@ void JpegReaderTest::testReadCMYK()
     CPPUNIT_ASSERT(checkRect(aBitmap, 1, 8, 8, Color(0xff, 0x00, 0x00), maxDelta));
     CPPUNIT_ASSERT(checkRect(aBitmap, 2, 8, 8, Color(0x00, 0xff, 0x00), maxDelta));
     CPPUNIT_ASSERT(checkRect(aBitmap, 3, 8, 8, Color(0x00, 0x00, 0xff), maxDelta));
+
+    CPPUNIT_ASSERT_EQUAL(4, getNumberOfImageComponents(aGraphic));
 }
 
 CPPUNIT_TEST_SUITE_REGISTRATION(JpegReaderTest);
diff --git a/vcl/source/filter/graphicfilter2.cxx b/vcl/source/filter/graphicfilter2.cxx
index ae181f4269b6..a5635563c4e4 100644
--- a/vcl/source/filter/graphicfilter2.cxx
+++ b/vcl/source/filter/graphicfilter2.cxx
@@ -96,6 +96,7 @@ void GraphicDescriptor::ImpConstruct()
     nFormat = GraphicFileFormat::NOT;
     nBitsPerPixel = 0;
     nPlanes = 0;
+    mnNumberOfImageComponents = 0;
 }
 
 bool GraphicDescriptor::ImpDetectBMP( SvStream& rStm, bool bExtendedInfo )
@@ -371,6 +372,7 @@ bool GraphicDescriptor::ImpDetectJPG( SvStream& rStm,  bool bExtendedInfo )
                                         .ReadUChar( nComponentsIdentifier )
                                         .ReadUChar( nSamplingFactor )
                                         .ReadUChar( nQuantizationTableDestinationSelector );
+                                    mnNumberOfImageComponents = nNumberOfImageComponents;
 
                                     // nSamplingFactor (lower nibble: vertical,
                                     // upper nibble: horizontal) is unused
diff --git a/vcl/source/gdi/pdfextoutdevdata.cxx b/vcl/source/gdi/pdfextoutdevdata.cxx
index 8543da75db9a..d74996ce2403 100644
--- a/vcl/source/gdi/pdfextoutdevdata.cxx
+++ b/vcl/source/gdi/pdfextoutdevdata.cxx
@@ -23,6 +23,7 @@
 #include <vcl/gfxlink.hxx>
 #include <vcl/dllapi.h>
 #include <vcl/metaact.hxx>
+#include <vcl/graphicfilter.hxx>
 #include <basegfx/polygon/b2dpolygon.hxx>
 #include <basegfx/polygon/b2dpolygontools.hxx>
 
@@ -837,6 +838,14 @@ bool PDFExtOutDevData::HasAdequateCompression( const Graphic &rGraphic,
     if (rGraphic.GetLink().GetDataSize() == 0)
         return false;
 
+    GfxLink aLink = rGraphic.GetLink();
+    SvMemoryStream aMemoryStream(const_cast<sal_uInt8*>(aLink.GetData()), aLink.GetDataSize(),
+                                 StreamMode::READ | StreamMode::WRITE);
+    GraphicDescriptor aDescriptor(aMemoryStream, nullptr);
+    if (aDescriptor.Detect(true) && aDescriptor.GetNumberOfImageComponents() == 4)
+        // 4 means CMYK, which is not handled.
+        return false;
+
     Size aSize = rGraphic.GetSizePixel();
 
     // small items better off as PNG anyway