Add core code for printing PDF data using PDFium

Enables printing PDFs to QPrinters via PDFium.

Bitmap to QImage conversion code based on code by Paulo Pinheiro
<paulovap.os@gmail.com>

Task-number: QTBUG-50556
Change-Id: I536200dc3dc56109624959b1d3d4644e4c20d1c0
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

4 files changed, 303 insertions, 0 deletions

diff --git a/src/core/core_common.pri b/src/core/core_common.pri
index 9c29aea71..721e8c71a 100644
--- a/src/core/core_common.pri
+++ b/src/core/core_common.pri
@@ -10,3 +10,4 @@ CHROMIUM_SRC_DIR = $$QTWEBENGINE_ROOT/$$getChromiumSrcDir()
 INCLUDEPATH += $$CHROMIUM_SRC_DIR
 
 qtHaveModule(positioning):QT += positioning
+qtHaveModule(printsupport):QT += printsupport
diff --git a/src/core/core_gyp_generator.pro b/src/core/core_gyp_generator.pro
index b2cd7b693..5196d6438 100644
--- a/src/core/core_gyp_generator.pro
+++ b/src/core/core_gyp_generator.pro
@@ -196,3 +196,8 @@ qtHaveModule(positioning) {
     HEADERS += location_provider_qt.h
     DEFINES += QT_USE_POSITIONING=1
 }
+
+qtHaveModule(printsupport) {
+    SOURCES += pdfium_printing_wrapper_qt.cpp
+    HEADERS += pdfium_printing_wrapper_qt.h
+}
diff --git a/src/core/pdfium_printing_wrapper_qt.cpp b/src/core/pdfium_printing_wrapper_qt.cpp
new file mode 100644
index 000000000..165ac743f
--- /dev/null
+++ b/src/core/pdfium_printing_wrapper_qt.cpp
@@ -0,0 +1,231 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtWebEngine module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "pdfium_printing_wrapper_qt.h"
+
+#include <QtCore/qhash.h>
+#include <QtGui/qimage.h>
+#include <QtGui/qpainter.h>
+#include <QtPrintSupport/qprinter.h>
+
+#include "third_party/pdfium/public/fpdf_doc.h"
+#include "third_party/pdfium/public/fpdfview.h"
+
+namespace QtWebEngineCore {
+int PdfiumPrintingWrapperQt::m_libraryUsers = 0;
+
+class PDFiumPageWrapper {
+public:
+    PDFiumPageWrapper(void *data, int pageIndex, int targetWidth, int targetHeight)
+        : m_pageData(FPDF_LoadPage(data, pageIndex))
+        , m_width(FPDF_GetPageWidth(m_pageData))
+        , m_height(FPDF_GetPageHeight(m_pageData))
+        , m_index(pageIndex)
+        , m_image(createImage(targetWidth, targetHeight))
+    {
+    }
+
+    PDFiumPageWrapper()
+        : m_pageData(nullptr)
+        , m_width(-1)
+        , m_height(-1)
+        , m_index(-1)
+        , m_image(QImage())
+    {
+    }
+
+    virtual ~PDFiumPageWrapper()
+    {
+        FPDF_ClosePage(m_pageData);
+    }
+
+    QImage image()
+    {
+        return m_image;
+    }
+
+private:
+    QImage createImage(int targetWidth, int targetHeight)
+    {
+        Q_ASSERT(m_pageData);
+        if (targetWidth <= 0)
+            targetWidth = m_width;
+
+        if (targetHeight <= 0)
+            targetHeight = m_height;
+
+        QImage image(targetWidth, targetHeight, QImage::Format_RGBA8888);
+        Q_ASSERT(!image.isNull());
+        image.fill(0xFFFFFFFF);
+
+        FPDF_BITMAP bitmap = FPDFBitmap_CreateEx(image.width(), image.height(),
+                                                 FPDFBitmap_BGRA,
+                                                 image.scanLine(0), image.bytesPerLine());
+        Q_ASSERT(bitmap);
+
+        FPDF_RenderPageBitmap(bitmap, m_pageData,
+                              0, 0, image.width(), image.height(),
+                              0, 0);
+        FPDFBitmap_Destroy(bitmap);
+        bitmap = nullptr;
+
+        // Map BGRA to RGBA as PDFium currently does not support RGBA bitmaps directly
+        for (int i = 0; i < image.height(); i++) {
+            uchar *pixels = image.scanLine(i);
+            for (int j = 0; j < image.width(); j++) {
+                qSwap(pixels[0], pixels[2]);
+                pixels += 4;
+            }
+        }
+        return image;
+    }
+
+private:
+    void *m_pageData;
+    int m_width;
+    int m_height;
+    int m_index;
+    QImage m_image;
+};
+
+
+PdfiumPrintingWrapperQt::PdfiumPrintingWrapperQt(const void *pdfData, size_t size, const char *password)
+{
+   Q_ASSERT(pdfData);
+   Q_ASSERT(size);
+   if (m_libraryUsers++ == 0)
+       FPDF_InitLibrary();
+
+   m_documentHandle = FPDF_LoadMemDocument(pdfData, static_cast<int>(size), password);
+   m_pageCount = FPDF_GetPageCount(m_documentHandle);
+}
+
+bool PdfiumPrintingWrapperQt::printOnPrinter(QPrinter &printer)
+{
+    if (!m_documentHandle || !m_pageCount) {
+        qWarning("Failure to print on printer %ls: invalid document.\n", qUtf16Printable(printer.printerName()));
+        return false;
+    }
+
+    int toPage = printer.toPage();
+    int fromPage = printer.fromPage();
+    bool ascendingOrder = true;
+
+    if (fromPage == 0 && toPage == 0) {
+        fromPage = 1;
+        toPage = m_pageCount;
+    }
+    fromPage = qMax(1, fromPage);
+    toPage = qMin(m_pageCount, toPage);
+
+    if (printer.pageOrder() == QPrinter::LastPageFirst) {
+        qSwap(fromPage, toPage);
+        ascendingOrder = false;
+    }
+
+    int documentCopies = printer.copyCount();
+    int pageCopies = 1;
+    if (printer.collateCopies()) {
+        pageCopies = documentCopies;
+        documentCopies = 1;
+    }
+
+    QRect printerPageRect = printer.pageRect();
+    int doubledPrinterWidth = 2 * printerPageRect.width();
+    int doubledPrinterHeight = 2 * printerPageRect.height();
+
+    QPainter painter;
+    if (!painter.begin(&printer)) {
+        qWarning("Failure to print on printer %ls: Could not open printer for painting.\n", qUtf16Printable(printer.printerName()));
+        return false;
+    }
+
+    QHash<int, PDFiumPageWrapper*> cachedPages;
+    for (int printedDocuments = 0; printedDocuments < documentCopies; printedDocuments++) {
+        int currentPageIndex = fromPage;
+        while (true) {
+            for (int printedPages = 0; printedPages < pageCopies; printedPages++) {
+                if (printer.printerState() == QPrinter::Aborted
+                        || printer.printerState() == QPrinter::Error)
+                    return false;
+
+                PDFiumPageWrapper *currentPageWrapper;
+                if (!cachedPages.contains(currentPageIndex - 1)) {
+                    currentPageWrapper
+                            = new PDFiumPageWrapper(m_documentHandle, currentPageIndex - 1
+                                                    , doubledPrinterWidth, doubledPrinterHeight);
+                    cachedPages.insert(currentPageIndex - 1, currentPageWrapper);
+                } else {
+                    currentPageWrapper = cachedPages.value(currentPageIndex - 1);
+                }
+
+                QImage currentImage = currentPageWrapper->image();
+                painter.drawImage(printerPageRect, currentImage, currentImage.rect());
+                if (printedPages < pageCopies - 1)
+                    printer.newPage();
+            }
+
+            if (currentPageIndex == toPage)
+                break;
+
+            if (ascendingOrder)
+                currentPageIndex++;
+            else
+                currentPageIndex--;
+
+            printer.newPage();
+        }
+        if (printedDocuments < documentCopies - 1)
+            printer.newPage();
+    }
+    painter.end();
+
+    qDeleteAll(cachedPages);
+
+    return true;
+}
+
+PdfiumPrintingWrapperQt::~PdfiumPrintingWrapperQt()
+{
+    FPDF_CloseDocument(m_documentHandle);
+    if (--m_libraryUsers == 0)
+        FPDF_DestroyLibrary();
+}
+
+}
diff --git a/src/core/pdfium_printing_wrapper_qt.h b/src/core/pdfium_printing_wrapper_qt.h
new file mode 100644
index 000000000..3aaf2b461
--- /dev/null
+++ b/src/core/pdfium_printing_wrapper_qt.h
@@ -0,0 +1,66 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtWebEngine module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef PDFIUM_PRINTING_WRAPPER_QT_H
+#define PDFIUM_PRINTING_WRAPPER_QT_H
+
+#include <QtCore/qglobal.h>
+
+QT_BEGIN_NAMESPACE
+class QPrinter;
+QT_END_NAMESPACE
+
+namespace QtWebEngineCore {
+
+class PdfiumPrintingWrapperQt
+{
+public:
+    PdfiumPrintingWrapperQt(const void *pdfData, size_t size, const char *password = nullptr);
+    virtual ~PdfiumPrintingWrapperQt();
+    bool printOnPrinter(QPrinter &printer);
+    int pageCount() const { return m_pageCount; }
+
+private:
+    static int m_libraryUsers;
+    void *m_documentHandle;
+    int m_pageCount;
+};
+
+} // namespace QtWebEngineCore
+#endif // PDFIUM_PRINTING_WRAPPER_QT_H