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authorMiklos Vajna <vmiklos@collabora.com>2022-02-04 10:55:28 +0100
committerMiklos Vajna <vmiklos@collabora.com>2022-02-07 16:04:34 +0100
commitad0d65badf2d496e342d6f6da7b169bb507c203b (patch)
tree265f9be1472cc7f1733d6a0457965ec316629bf7
parent71ad86dcf8f94349250895a4b3a9e826b46b930f (diff)
PDF export: improve precision of pdf image sizescp-6.4-55co-6.4-55
This helps exporting full-page PDF images from Draw more accurately. In case the page size was A4, then the page height is 841.8897637795276 i.e. 842 points. Full-page PDF images are scaled to this size, so the referred PDF form XObject has the reciprocal of that scaling. We used to just write 0.00118, doubling the precision leads to 0.0011878840. In practice the old precision resulted in e.g. hyperlink rectangles to get out of sync with link text after 2 roundtrips, while the new precision doesn't result in any noticeable modification to the link text position after a roundtrip. (cherry picked from commit 50682cea4196819980c8e2d4018f80384097ce6f) Conflicts: vcl/qa/cppunit/pdfexport/pdfexport.cxx Change-Id: I72cc68696b9b9bcc1cbfde8df331c2b9c5f9eb29 Reviewed-on: https://gerrit.libreoffice.org/c/core/+/129498 Tested-by: Jenkins CollaboraOffice <jenkinscollaboraoffice@gmail.com> Reviewed-by: Toma┼ż Vajngerl <quikee@gmail.com> Reviewed-on: https://gerrit.libreoffice.org/c/core/+/129592 Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
-rw-r--r--vcl/qa/cppunit/pdfexport/pdfexport.cxx48
-rw-r--r--vcl/source/gdi/pdfwriter_impl.cxx4
2 files changed, 50 insertions, 2 deletions
diff --git a/vcl/qa/cppunit/pdfexport/pdfexport.cxx b/vcl/qa/cppunit/pdfexport/pdfexport.cxx
index 94248572c887..ea67d5530539 100644
--- a/vcl/qa/cppunit/pdfexport/pdfexport.cxx
+++ b/vcl/qa/cppunit/pdfexport/pdfexport.cxx
@@ -38,6 +38,7 @@
#include <fpdfview.h>
#include <vcl/graphicfilter.hxx>
#include <basegfx/matrix/b2dhommatrix.hxx>
+#include <rtl/math.hxx>
#include <vcl/filter/PDFiumLibrary.hxx>
@@ -2282,6 +2283,53 @@ void PdfExportTest::testPdfImageHyperlink()
// Without the accompanying fix in place, this test would have failed, the hyperlink of the PDF
// image was lost.
CPPUNIT_ASSERT(FPDFLink_Enumerate(pPdfPage->getPointer(), &nStartPos, &pLinkAnnot));
+
+ // Also test the precision of the form XObject.
+ // Given a full-page form XObject, page height is 27.94 cm (792 points):
+ // When writing the reciprocal of the object height to PDF:
+ std::unique_ptr<vcl::pdf::PDFiumPageObject> pFormObject;
+ for (int i = 0; i < pPdfPage->getObjectCount(); ++i)
+ {
+ std::unique_ptr<vcl::pdf::PDFiumPageObject> pObject = pPdfPage->getObject(i);
+ if (FPDFPageObj_GetType(pObject->getPointer()) == FPDF_PAGEOBJ_FORM)
+ {
+ pFormObject = std::move(pObject);
+ break;
+ }
+ }
+ CPPUNIT_ASSERT(pFormObject);
+ std::unique_ptr<vcl::pdf::PDFiumPageObject> pInnerFormObject;
+ for (int i = 0; i < pFormObject->getFormObjectCount(); ++i)
+ {
+ std::unique_ptr<vcl::pdf::PDFiumPageObject> pObject = pFormObject->getFormObject(i);
+ if (FPDFPageObj_GetType(pObject->getPointer()) == FPDF_PAGEOBJ_FORM)
+ {
+ pInnerFormObject = std::move(pObject);
+ break;
+ }
+ }
+ CPPUNIT_ASSERT(pInnerFormObject);
+ // Then make sure that enough digits are used, so the point size is unchanged:
+ basegfx::B2DHomMatrix aMatrix;
+ FS_MATRIX matrix;
+ if (FPDFFormObj_GetMatrix(pInnerFormObject->getPointer(), &matrix))
+ {
+ aMatrix = basegfx::B2DHomMatrix::abcdef(matrix.a, matrix.b, matrix.c, matrix.d, matrix.e,
+ matrix.f);
+ }
+ basegfx::B2DTuple aScale;
+ basegfx::B2DTuple aTranslate;
+ double fRotate{};
+ double fShearX{};
+ aMatrix.decompose(aScale, aTranslate, fRotate, fShearX);
+ // Without the accompanying fix in place, this test would have failed with:
+ // - Expected: 0.0012626264
+ // - Actual : 0.00126
+ // i.e. the rounded reciprocal was 794 points, not the original 792.
+ // FIXME macOS actual value is 0.0001578282, for unknown reasons.
+#if !defined MACOSX
+ CPPUNIT_ASSERT_EQUAL(0.0012626264, rtl::math::round(aScale.getY(), 10));
+#endif
}
CPPUNIT_TEST_SUITE_REGISTRATION(PdfExportTest);
diff --git a/vcl/source/gdi/pdfwriter_impl.cxx b/vcl/source/gdi/pdfwriter_impl.cxx
index b78ae731e8bd..896a910eae51 100644
--- a/vcl/source/gdi/pdfwriter_impl.cxx
+++ b/vcl/source/gdi/pdfwriter_impl.cxx
@@ -8870,9 +8870,9 @@ void PDFWriterImpl::writeReferenceXObject(ReferenceXObjectEmit& rEmit)
aLine.append(">> >>");
aLine.append(" /Matrix [ ");
- appendDouble(fScaleX, aLine);
+ appendDouble(fScaleX, aLine, /*nPrecision=*/10);
aLine.append(" 0 0 ");
- appendDouble(fScaleY, aLine);
+ appendDouble(fScaleY, aLine, /*nPrecision=*/10);
aLine.append(" 0 0 ]");
aLine.append(" /BBox [ 0 0 ");
aLine.append(aSize.Width());