vcl: add initial PDF import-as-graphic filter

This allows Insert -> Image e.g. in Writer to read a PDF file, and
insert the metafile equivalent of the first page into the document.

Currently the original PDF document is lost on import (unlike when
inserting an SVG file).

Change-Id: Ib0472c5d9bd9a1da054353fa3a3a638a1052721e
Reviewed-on: https://gerrit.libreoffice.org/26586
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Jenkins <ci@libreoffice.org>

1 files changed, 107 insertions, 0 deletions

diff --git a/vcl/source/filter/ipdf/pdfread.cxx b/vcl/source/filter/ipdf/pdfread.cxx
new file mode 100644
index 000000000000..cc63415eba6d
--- /dev/null
+++ b/vcl/source/filter/ipdf/pdfread.cxx
@@ -0,0 +1,107 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#include "pdfread.hxx"
+
+#include <com/sun/star/beans/XPropertySet.hpp>
+#include <com/sun/star/document/XFilter.hpp>
+#include <com/sun/star/document/XImporter.hpp>
+#include <com/sun/star/drawing/XDrawPagesSupplier.hpp>
+#include <com/sun/star/frame/Desktop.hpp>
+#include <com/sun/star/io/XStream.hpp>
+#include <com/sun/star/lang/XMultiServiceFactory.hpp>
+
+#include <comphelper/processfactory.hxx>
+#include <comphelper/propertyvalue.hxx>
+#include <comphelper/scopeguard.hxx>
+#include <unotools/streamwrap.hxx>
+#include <vcl/wmf.hxx>
+
+using namespace com::sun::star;
+
+namespace
+{
+
+/// Imports a PDF stream into Draw.
+uno::Reference<lang::XComponent> importIntoDraw(SvStream& rStream)
+{
+    // Create an empty Draw component.
+    uno::Reference<frame::XDesktop2> xDesktop = css::frame::Desktop::create(comphelper::getProcessComponentContext());
+    uno::Reference<frame::XComponentLoader> xComponentLoader(xDesktop, uno::UNO_QUERY);
+    uno::Sequence<beans::PropertyValue> aLoadArguments =
+    {
+        comphelper::makePropertyValue("Hidden", true)
+    };
+    uno::Reference<lang::XComponent> xComponent = xComponentLoader->loadComponentFromURL("private:factory/sdraw", "_default", 0, aLoadArguments);
+
+    // Import the PDF into it.
+    uno::Reference<lang::XMultiServiceFactory> xMultiServiceFactory(comphelper::getProcessServiceFactory());
+    // Need to go via FilterFactory, otherwise XmlFilterAdaptor::initialize() is not called.
+    uno::Reference<lang::XMultiServiceFactory> xFilterFactory(xMultiServiceFactory->createInstance("com.sun.star.document.FilterFactory"), uno::UNO_QUERY);
+    uno::Reference<document::XFilter> xFilter(xFilterFactory->createInstanceWithArguments("draw_pdf_import", uno::Sequence<uno::Any>()), uno::UNO_QUERY);
+    uno::Reference<document::XImporter> xImporter(xFilter, uno::UNO_QUERY);
+    xImporter->setTargetDocument(xComponent);
+
+    uno::Reference<io::XStream> xStream(new utl::OStreamWrapper(rStream));
+    uno::Sequence<beans::PropertyValue> aImportArguments =
+    {
+        // XmlFilterAdaptor::importImpl() mandates URL, even if it's empty.
+        comphelper::makePropertyValue("URL", OUString()),
+        comphelper::makePropertyValue("InputStream", xStream),
+    };
+
+    if (xFilter->filter(aImportArguments))
+        return xComponent;
+    else
+    {
+        xComponent->dispose();
+        return uno::Reference<lang::XComponent>();
+    }
+}
+
+}
+
+VCL_DLLPUBLIC bool ImportPDF(SvStream& rStream, Graphic& rGraphic)
+{
+    uno::Reference<lang::XComponent> xComponent = importIntoDraw(rStream);
+    if (!xComponent.is())
+        return false;
+    comphelper::ScopeGuard aGuard([&xComponent]()
+    {
+        xComponent->dispose();
+    });
+
+    // Get the preview of the first page.
+    uno::Reference<drawing::XDrawPagesSupplier> xDrawPagesSupplier(xComponent, uno::UNO_QUERY);
+    uno::Reference<drawing::XDrawPages> xDrawPages = xDrawPagesSupplier->getDrawPages();
+    if (xDrawPages->getCount() <= 0)
+        return false;
+
+    uno::Reference<beans::XPropertySet> xFirstPage(xDrawPages->getByIndex(0), uno::UNO_QUERY);
+    uno::Sequence<sal_Int8> aSequence;
+    if (!(xFirstPage->getPropertyValue("Preview") >>= aSequence))
+        return false;
+
+    if (!aSequence.hasElements())
+        return false;
+
+    // Convert it into a GDIMetaFile.
+    SvMemoryStream aPreviewStream(aSequence.getLength());
+    aPreviewStream.WriteBytes(aSequence.getArray(), aSequence.getLength());
+    aPreviewStream.Seek(0);
+    GDIMetaFile aMtf;
+    if (!ConvertWMFToGDIMetaFile(aPreviewStream, aMtf))
+        return false;
+
+    rGraphic = aMtf;
+
+    return true;
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */