vcl PDF export: fix re-exporting PDF images with page-level rotation

PDF images are effectively 1 page PDF documents. The page object may
have a /Rotate key, which was simply ignored before. We turn page
objects into form XObjects on PDF export, such rotation can be expressed
with a /Matrix key.

Add support for the 90 degrees rotation case, this can be generalized
later if wanted.

Change-Id: I55a4f63e0b986637ccdeba0b783f1db9a85c4d93
Reviewed-on: https://gerrit.libreoffice.org/82154
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
Tested-by: Jenkins

2 files changed, 28 insertions, 0 deletions

diff --git a/vcl/qa/cppunit/pdfexport/data/pdf-image-resource-inline-xobject-ref.pdf b/vcl/qa/cppunit/pdfexport/data/pdf-image-resource-inline-xobject-ref.pdf
index b62068eae9dd..739a80c4766d 100644
--- a/vcl/qa/cppunit/pdfexport/data/pdf-image-resource-inline-xobject-ref.pdf
+++ b/vcl/qa/cppunit/pdfexport/data/pdf-image-resource-inline-xobject-ref.pdf
diff --git a/vcl/qa/cppunit/pdfexport/pdfexport.cxx b/vcl/qa/cppunit/pdfexport/pdfexport.cxx
index ba62f301bec4..22585a9827eb 100644
--- a/vcl/qa/cppunit/pdfexport/pdfexport.cxx
+++ b/vcl/qa/cppunit/pdfexport/pdfexport.cxx
@@ -36,6 +36,7 @@
 #include <fpdf_doc.h>
 #include <fpdfview.h>
 #include <vcl/graphicfilter.hxx>
+#include <basegfx/matrix/b2dhommatrix.hxx>
 
 using namespace ::com::sun::star;
 
@@ -1877,6 +1878,33 @@ void PdfExportTest::testPdfImageResourceInlineXObjectRef()
     // - Actual  : 0
     // i.e. the sub-form was missing its image.
     CPPUNIT_ASSERT_EQUAL(1, FPDFFormObj_CountObjects(pFormObject));
+
+    // Check if the inner form object (original page object in the pdf image) has the correct
+    // rotation.
+    FPDF_PAGEOBJECT pInnerFormObject = FPDFFormObj_GetObject(pFormObject, 0);
+    CPPUNIT_ASSERT_EQUAL(FPDF_PAGEOBJ_FORM, FPDFPageObj_GetType(pInnerFormObject));
+    CPPUNIT_ASSERT_EQUAL(1, FPDFFormObj_CountObjects(pInnerFormObject));
+    FPDF_PAGEOBJECT pImage = FPDFFormObj_GetObject(pInnerFormObject, 0);
+    CPPUNIT_ASSERT_EQUAL(FPDF_PAGEOBJ_IMAGE, FPDFPageObj_GetType(pImage));
+    double fA = 0;
+    double fB = 0;
+    double fC = 0;
+    double fD = 0;
+    double fE = 0;
+    double fF = 0;
+    FPDFFormObj_GetMatrix(pInnerFormObject, &fA, &fB, &fC, &fD, &fE, &fF);
+    basegfx::B2DHomMatrix aMat{ fA, fC, fE, fB, fD, fF };
+    basegfx::B2DTuple aScale;
+    basegfx::B2DTuple aTranslate;
+    double fRotate = 0;
+    double fShearX = 0;
+    aMat.decompose(aScale, aTranslate, fRotate, fShearX);
+    int nRotateDeg = basegfx::rad2deg(fRotate);
+    // Without the accompanying fix in place, this test would have failed with:
+    // - Expected: -90
+    // - Actual  : 0
+    // i.e. rotation was lost on pdf export.
+    CPPUNIT_ASSERT_EQUAL(-90, nRotateDeg);
 }
 
 CPPUNIT_TEST_SUITE_REGISTRATION(PdfExportTest);