tdf#74670 tdf#91286 PPTX XLSX export: save image once

Impress and Calc used to dump the same image file
as many times as it was featured in the document,
resulting redundant, sometimes huge documents.

Note: using only checksum to recognize image duplication
is a regression, because checksum collision results
image loss. This is a very unlikely event, and
the following commits have got the same problem.
The solution is comparing the images with the same
checksum byte for byte.

See also commit b484e9814c66d8d51cea974390963a6944bc9d73
"tdf#83227 oox: reuse RelId in DML/VML export for the same graphic"
and commit 797fef38612fb2fd62d1f6591619b9361e526bca
"tdf#118535 DOCX export: save header image once".

Change-Id: I9f233d521941381746634cf4f9b5991da0dadda9
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/131928
Tested-by: László Németh <nemeth@numbertext.org>
Reviewed-by: László Németh <nemeth@numbertext.org>

3 files changed, 28 insertions, 0 deletions

diff --git a/sd/qa/unit/data/odp/tdf74670.odp b/sd/qa/unit/data/odp/tdf74670.odp
new file mode 100644
index 000000000000..98e223eb0725
--- /dev/null
+++ b/sd/qa/unit/data/odp/tdf74670.odp
diff --git a/sd/qa/unit/export-tests-ooxml3.cxx b/sd/qa/unit/export-tests-ooxml3.cxx
index 776d436b7edf..3f4bec336ef1 100644
--- a/sd/qa/unit/export-tests-ooxml3.cxx
+++ b/sd/qa/unit/export-tests-ooxml3.cxx
@@ -106,6 +106,7 @@ public:
     void testTdf147121();
     void testTdf140912_PicturePlaceholder();
     void testEnhancedPathViewBox();
+    void testTdf74670();
 
     CPPUNIT_TEST_SUITE(SdOOXMLExportTest3);
 
@@ -182,6 +183,7 @@ public:
     CPPUNIT_TEST(testTdf147121);
     CPPUNIT_TEST(testTdf140912_PicturePlaceholder);
     CPPUNIT_TEST(testEnhancedPathViewBox);
+    CPPUNIT_TEST(testTdf74670);
     CPPUNIT_TEST_SUITE_END();
 
     virtual void registerNamespaces(xmlXPathContextPtr& pXmlXPathCtx) override
@@ -1893,6 +1895,30 @@ void SdOOXMLExportTest3::testEnhancedPathViewBox()
     CPPUNIT_ASSERT_EQUAL(sal_Int32(2045), aBoundRectangle.Width);
 }
 
+void SdOOXMLExportTest3::testTdf74670()
+{
+    ::sd::DrawDocShellRef xDocShRef
+        = loadURL(m_directories.getURLFromSrc(u"/sd/qa/unit/data/odp/tdf74670.odp"), ODP);
+    utl::TempFile tmpfile;
+    xDocShRef = saveAndReload(xDocShRef.get(), PPTX, &tmpfile);
+    xDocShRef->DoClose();
+
+    uno::Reference<packages::zip::XZipFileAccess2> xNameAccess
+        = packages::zip::ZipFileAccess::createWithURL(comphelper::getComponentContext(m_xSFactory),
+                                                      tmpfile.GetURL());
+    const uno::Sequence<OUString> aNames(xNameAccess->getElementNames());
+    int nImageFiles = 0;
+    for (const auto& rElementName : aNames)
+        if (rElementName.startsWith("ppt/media/image"))
+            nImageFiles++;
+
+    // Without the accompanying fix in place, this test would have failed with:
+    // - Expected: 1
+    // - Actual  : 2
+    // i.e. the embedded picture would have been saved twice.
+    CPPUNIT_ASSERT_EQUAL(1, nImageFiles);
+}
+
 CPPUNIT_TEST_SUITE_REGISTRATION(SdOOXMLExportTest3);
 
 CPPUNIT_PLUGIN_IMPLEMENT();
diff --git a/sd/source/filter/eppt/pptx-epptooxml.cxx b/sd/source/filter/eppt/pptx-epptooxml.cxx
index 07be6521d678..8823cbd00d53 100644
--- a/sd/source/filter/eppt/pptx-epptooxml.cxx
+++ b/sd/source/filter/eppt/pptx-epptooxml.cxx
@@ -428,6 +428,7 @@ bool PowerPointExport::importDocument() noexcept
 bool PowerPointExport::exportDocument()
 {
     DrawingML::ResetCounters();
+    DrawingML::PushExportGraphics();
     maShapeMap.clear();
 
     mXModel = getModel();
@@ -504,6 +505,7 @@ bool PowerPointExport::exportDocument()
 
     commitStorage();
 
+    DrawingML::PopExportGraphics();
     maShapeMap.clear();
     maAuthors.clear();
     maRelId.clear();