pdf: preserve the original page dimensions on import

Also allow for rendering PDFs to images at custom
resolution, instead of hard-coded (old hard-coded
value of 96 dpi is now default arguments).

Change-Id: Ia5b52f72d6ce7130a2debc7c6f86504aa041bdc8
Reviewed-on: https://gerrit.libreoffice.org/54786
Reviewed-by: Jan Holesovsky <kendy@collabora.com>
Tested-by: Jan Holesovsky <kendy@collabora.com>

3 files changed, 40 insertions, 20 deletions

diff --git a/include/vcl/pdfread.hxx b/include/vcl/pdfread.hxx
index 8fd840685248..5d79c6d38146 100644
--- a/include/vcl/pdfread.hxx
+++ b/include/vcl/pdfread.hxx
@@ -21,11 +21,16 @@ VCL_DLLPUBLIC bool ImportPDF(SvStream& rStream, Bitmap &rBitmap,
                              size_t nPageIndex,
                              css::uno::Sequence<sal_Int8> &rPdfFata,
                              sal_uInt64 nPos = STREAM_SEEK_TO_BEGIN,
-                             sal_uInt64 nSize = STREAM_SEEK_TO_END);
-VCL_DLLPUBLIC bool ImportPDF(SvStream& rStream, Graphic& rGraphic);
+                             sal_uInt64 nSize = STREAM_SEEK_TO_END,
+                             const double fResolutionDPI = 96.);
 
-VCL_DLLPUBLIC size_t ImportPDF(const OUString& rURL, std::vector<Bitmap>& rBitmaps,
-                               css::uno::Sequence<sal_Int8>& rPdfData);
+VCL_DLLPUBLIC bool ImportPDF(SvStream& rStream, Graphic& rGraphic,
+                             const double fResolutionDPI = 96.);
+
+VCL_DLLPUBLIC size_t ImportPDF(const OUString& rURL,
+                               std::vector<Bitmap>& rBitmaps,
+                               css::uno::Sequence<sal_Int8>& rPdfData,
+                               const double fResolutionDPI = 96.);
 }
 
 #endif // INCLUDED_VCL_SOURCE_FILTER_IPDF_PDFREAD_HXX
diff --git a/sd/source/filter/pdf/sdpdffilter.cxx b/sd/source/filter/pdf/sdpdffilter.cxx
index 4f7bd4ed0a6c..01e6ee5623de 100644
--- a/sd/source/filter/pdf/sdpdffilter.cxx
+++ b/sd/source/filter/pdf/sdpdffilter.cxx
@@ -99,9 +99,12 @@ bool SdPdfFilter::Import()
     const OUString aFileName(
         mrMedium.GetURLObject().GetMainURL(INetURLObject::DecodeMechanism::NONE));
 
+    // Rendering resolution.
+    const double dResolutionDPI = 96.;
+
     uno::Sequence<sal_Int8> aPdfData;
     std::vector<Bitmap> aBitmaps;
-    if (vcl::ImportPDF(aFileName, aBitmaps, aPdfData) == 0)
+    if (vcl::ImportPDF(aFileName, aBitmaps, aPdfData, dResolutionDPI) == 0)
         return false;
 
     // Prepare the link with the PDF stream.
@@ -129,8 +132,12 @@ bool SdPdfFilter::Import()
 
         // Create the page and insert the Graphic.
         SdPage* pPage = mrDocument.GetSdPage(nPageNumber++, PageKind::Standard);
-        const Size aGrfSize(OutputDevice::LogicToLogic(aGraphic.GetPrefSize(), aGraphic.GetPrefMapMode(),
-                                                       MapMode(MapUnit::Map100thMM)));
+        Size aGrfSize(OutputDevice::LogicToLogic(aGraphic.GetPrefSize(), aGraphic.GetPrefMapMode(),
+                                                 MapMode(MapUnit::Map100thMM)));
+
+        // Resize to original size based on 72 dpi to preserve page size.
+        aGrfSize = Size(aGrfSize.Width() * 72. / dResolutionDPI,
+                        aGrfSize.Height() * 72. / dResolutionDPI);
 
         // Make the page size match the rendered image.
         pPage->SetSize(aGrfSize);
diff --git a/vcl/source/filter/ipdf/pdfread.cxx b/vcl/source/filter/ipdf/pdfread.cxx
index 52d8e7277719..f61c4062fb37 100644
--- a/vcl/source/filter/ipdf/pdfread.cxx
+++ b/vcl/source/filter/ipdf/pdfread.cxx
@@ -58,15 +58,16 @@ int CompatibleWriter::WriteBlockCallback(FPDF_FILEWRITE* pFileWrite, const void*
 }
 
 /// Convert to inch, then assume 96 DPI.
-double pointToPixel(double fPoint)
+inline double pointToPixel(const double fPoint, const double fResolutionDPI)
 {
-    return fPoint / 72 * 96;
+    return fPoint * fResolutionDPI / 72.;
 }
 
 /// Does PDF to bitmap conversion using pdfium.
 size_t generatePreview(SvStream& rStream, std::vector<Bitmap>& rBitmaps,
                        sal_uInt64 nPos, sal_uInt64 nSize,
-                       const size_t nFirstPage = 0, int nPages = 1)
+                       const size_t nFirstPage = 0, int nPages = 1,
+                       const double fResolutionDPI = 96.)
 {
     FPDF_LIBRARY_CONFIG aConfig;
     aConfig.version = 2;
@@ -97,8 +98,8 @@ size_t generatePreview(SvStream& rStream, std::vector<Bitmap>& rBitmaps,
             break;
 
         // Returned unit is points, convert that to pixel.
-        const size_t nPageWidth = pointToPixel(FPDF_GetPageWidth(pPdfPage));
-        const size_t nPageHeight = pointToPixel(FPDF_GetPageHeight(pPdfPage));
+        const size_t nPageWidth = pointToPixel(FPDF_GetPageWidth(pPdfPage), fResolutionDPI);
+        const size_t nPageHeight = pointToPixel(FPDF_GetPageHeight(pPdfPage), fResolutionDPI);
         FPDF_BITMAP pPdfBitmap = FPDFBitmap_Create(nPageWidth, nPageHeight, /*alpha=*/1);
         if (!pPdfBitmap)
             break;
@@ -201,13 +202,17 @@ bool getCompatibleStream(SvStream& rInStream, SvStream& rOutStream,
 }
 #else
 size_t generatePreview(SvStream&, std::vector<Bitmap>&,
-                     sal_uInt64 nPos, sal_uInt64 nSize,
-                     size_t nFirstPage = 0, int nLastPage = 0)
+                       sal_uInt64 nPos, sal_uInt64 nSize,
+                       size_t nFirstPage = 0, int nLastPage = 0,
+                       const double fResolutionDPI = 96.)
 {
     (void)rStream;
     (void)rBitmap;
     (void)nPos;
     (void)nSize;
+    (void)nFirstPage;
+    (void)nLastPage;
+    (void)fResolutionDPI;
 
     return false;
 }
@@ -229,11 +234,12 @@ namespace vcl
 bool ImportPDF(SvStream& rStream, Bitmap &rBitmap,
                size_t nPageIndex,
                css::uno::Sequence<sal_Int8> &rPdfData,
-               sal_uInt64 nPos, sal_uInt64 nSize)
+               sal_uInt64 nPos, sal_uInt64 nSize,
+               const double fResolutionDPI)
 {
     // Get the preview of the first page.
     std::vector<Bitmap> aBitmaps;
-    if (generatePreview(rStream, aBitmaps, nPos, nSize, nPageIndex, 1) != 1 ||
+    if (generatePreview(rStream, aBitmaps, nPos, nSize, nPageIndex, 1, fResolutionDPI) != 1 ||
         aBitmaps.empty())
         return false;
 
@@ -253,11 +259,12 @@ bool ImportPDF(SvStream& rStream, Bitmap &rBitmap,
 }
 
 
-bool ImportPDF(SvStream& rStream, Graphic& rGraphic)
+bool ImportPDF(SvStream& rStream, Graphic& rGraphic,
+               const double fResolutionDPI)
 {
     uno::Sequence<sal_Int8> aPdfData;
     Bitmap aBitmap;
-    bool bRet = ImportPDF(rStream, aBitmap, 0, aPdfData);
+    bool bRet = ImportPDF(rStream, aBitmap, 0, aPdfData, fResolutionDPI);
     rGraphic = aBitmap;
     rGraphic.setPdfData(std::make_shared<css::uno::Sequence<sal_Int8>>(aPdfData));
     rGraphic.setPageNumber(0); // We currently import only the first page.
@@ -265,12 +272,13 @@ bool ImportPDF(SvStream& rStream, Graphic& rGraphic)
 }
 
 size_t ImportPDF(const OUString& rURL, std::vector<Bitmap>& rBitmaps,
-                 css::uno::Sequence<sal_Int8>& rPdfData)
+                 css::uno::Sequence<sal_Int8>& rPdfData,
+                 const double fResolutionDPI)
 {
     std::unique_ptr<SvStream> xStream(
         ::utl::UcbStreamHelper::CreateStream(rURL, StreamMode::READ | StreamMode::SHARE_DENYNONE));
 
-    if (generatePreview(*xStream, rBitmaps, STREAM_SEEK_TO_BEGIN, STREAM_SEEK_TO_END, 0, -1) == 0)
+    if (generatePreview(*xStream, rBitmaps, STREAM_SEEK_TO_BEGIN, STREAM_SEEK_TO_END, 0, -1, fResolutionDPI) == 0)
         return 0;
 
     // Save the original PDF stream for later use.