SVG viewer: Add export option.

Add an option to export an image giving a size. This can be
used for creating High DPI icons from SVG files among other things.

Task-number: QTBUG-49374
Change-Id: I0437889961bc6e646667c5165584002f7ab4d952
Reviewed-by: aavit <eirik.aavitsland@theqtcompany.com>

7 files changed, 363 insertions, 6 deletions

diff --git a/examples/svg/svgviewer/exportdialog.cpp b/examples/svg/svgviewer/exportdialog.cpp
new file mode 100644
index 0000000..04c9e12
--- /dev/null
+++ b/examples/svg/svgviewer/exportdialog.cpp
@@ -0,0 +1,208 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** You may use this file under the terms of the BSD license as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "exportdialog.h"
+
+#include <QApplication>
+#include <QDesktopWidget>
+#include <QDialogButtonBox>
+#include <QFileDialog>
+#include <QFormLayout>
+#include <QHBoxLayout>
+#include <QMessageBox>
+#include <QLabel>
+#include <QLineEdit>
+#include <QPushButton>
+#include <QSpinBox>
+#include <QToolButton>
+#include <QVBoxLayout>
+
+#include <QImageWriter>
+
+#include <QDebug>
+
+#include <QDir>
+#include <QFileInfo>
+
+enum { exportMinimumSize = 1, exportMaximumSize = 2000 };
+
+ExportDialog::ExportDialog(QWidget *parent)
+    : QDialog(parent)
+    , m_fileNameLineEdit(new QLineEdit(this))
+    , m_widthSpinBox(new QSpinBox(this))
+    , m_heightSpinBox(new QSpinBox(this))
+    , m_aspectRatio(1)
+{
+    typedef void (QSpinBox::*QSpinBoxIntSignal)(int);
+
+    setWindowFlags(windowFlags() & ~Qt::WindowContextHelpButtonHint);
+    setWindowTitle(tr("Export"));
+
+    QFormLayout *formLayout = new QFormLayout(this);
+
+    QHBoxLayout *fileLayout = new QHBoxLayout;
+    fileLayout->addWidget(m_fileNameLineEdit);
+    m_fileNameLineEdit->setMinimumWidth(QApplication::desktop()->availableGeometry(this).width() / 6);
+    QPushButton *browseButton = new QPushButton(tr("Browse..."), this);
+    fileLayout->addWidget(browseButton);
+    connect(browseButton, &QAbstractButton::clicked, this, &ExportDialog::browse);
+    formLayout->addRow(tr("File:"), fileLayout);
+
+    QHBoxLayout *sizeLayout = new QHBoxLayout;
+    sizeLayout->addStretch();
+    m_widthSpinBox->setMinimum(exportMinimumSize);
+    m_widthSpinBox->setMaximum(exportMaximumSize);
+    connect(m_widthSpinBox, static_cast<QSpinBoxIntSignal>(&QSpinBox::valueChanged),
+            this, &ExportDialog::exportWidthChanged);
+    sizeLayout->addWidget(m_widthSpinBox);
+    //: Multiplication, as in 32x32
+    sizeLayout->addWidget(new QLabel(tr("x")));
+    m_heightSpinBox->setMinimum(exportMinimumSize);
+    m_heightSpinBox->setMaximum(exportMaximumSize);
+    connect(m_heightSpinBox, static_cast<QSpinBoxIntSignal>(&QSpinBox::valueChanged),
+            this, &ExportDialog::exportHeightChanged);
+    sizeLayout->addWidget(m_heightSpinBox);
+    QToolButton *resetButton = new QToolButton(this);
+    resetButton->setIcon(QIcon(":/qt-project.org/styles/commonstyle/images/refresh-32.png"));
+    sizeLayout->addWidget(resetButton);
+    connect(resetButton, &QAbstractButton::clicked, this, &ExportDialog::resetExportSize);
+    formLayout->addRow(tr("Size:"), sizeLayout);
+
+    QDialogButtonBox *buttonBox = new QDialogButtonBox(QDialogButtonBox::Ok | QDialogButtonBox::Cancel, this);
+    connect(buttonBox, &QDialogButtonBox::accepted, this, &QDialog::accept);
+    connect(buttonBox, &QDialogButtonBox::rejected, this, &QDialog::reject);
+    formLayout->addRow(buttonBox);
+}
+
+void ExportDialog::accept()
+{
+    const QString fileName = exportFileName();
+    if (fileName.isEmpty()) {
+        QMessageBox::warning(this, windowTitle(), tr("Please enter a file name"));
+        return;
+    }
+    QFileInfo fi(fileName);
+    if (fi.exists()) {
+        const QString question = tr("%1 already exists.\nWould you like to overwrite it?").arg(QDir::toNativeSeparators(fileName));
+        if (QMessageBox::question(this, windowTitle(), question, QMessageBox::Yes | QMessageBox::No) !=  QMessageBox::Yes)
+            return;
+    }
+    QDialog::accept();
+}
+
+QSize ExportDialog::exportSize() const
+{
+    return QSize(m_widthSpinBox->value(), m_heightSpinBox->value());
+}
+
+void ExportDialog::setExportSize(const QSize &size)
+{
+    m_defaultSize = size;
+    QSizeF defaultSizeF(m_defaultSize);
+    m_aspectRatio = defaultSizeF.width() / defaultSizeF.height();
+    setExportWidthBlocked(size.width());
+    setExportHeightBlocked(size.height());
+}
+
+void ExportDialog::resetExportSize()
+{
+    setExportWidthBlocked(m_defaultSize.width());
+    setExportHeightBlocked(m_defaultSize.height());
+}
+
+void ExportDialog::setExportWidthBlocked(int width)
+{
+    if (m_widthSpinBox->value() != width) {
+        const bool blockSignals = m_widthSpinBox->blockSignals(true);
+        m_widthSpinBox->setValue(width);
+        m_widthSpinBox->blockSignals(blockSignals);
+    }
+}
+
+void ExportDialog::setExportHeightBlocked(int height)
+{
+    if (m_heightSpinBox->value() != height) {
+        const bool blockSignals = m_heightSpinBox->blockSignals(true);
+        m_heightSpinBox->setValue(height);
+        m_heightSpinBox->blockSignals(blockSignals);
+    }
+}
+
+void ExportDialog::exportWidthChanged(int width)
+{
+    const bool square = m_defaultSize.width() == m_defaultSize.height();
+    setExportHeightBlocked(square ? width : qRound(qreal(width) / m_aspectRatio));
+}
+
+void ExportDialog::exportHeightChanged(int height)
+{
+    const bool square = m_defaultSize.width() == m_defaultSize.height();
+    setExportWidthBlocked(square ? height : qRound(qreal(height) * m_aspectRatio));
+}
+
+QString ExportDialog::exportFileName() const
+{
+    return QDir::cleanPath(m_fileNameLineEdit->text().trimmed());
+}
+
+void ExportDialog::setExportFileName(const QString &f)
+{
+    m_fileNameLineEdit->setText(QDir::toNativeSeparators(f));
+}
+
+void ExportDialog::browse()
+{
+    QFileDialog fileDialog(this);
+    fileDialog.setAcceptMode(QFileDialog::AcceptSave);
+    const QString fileName = exportFileName();
+    if (!fileName.isEmpty())
+        fileDialog.setDirectory(QFileInfo(fileName).absolutePath());
+    QStringList mimeTypes;
+    foreach (const QByteArray &mimeType, QImageWriter::supportedMimeTypes())
+        mimeTypes.append(QLatin1String(mimeType));
+    fileDialog.setMimeTypeFilters(mimeTypes);
+    const int pngIndex = mimeTypes.indexOf("image/png");
+    if (pngIndex >= 0) {
+        fileDialog.selectMimeTypeFilter(mimeTypes.at(pngIndex));
+        fileDialog.setDefaultSuffix("png");
+    }
+    if (fileDialog.exec() == QDialog::Accepted)
+        setExportFileName(fileDialog.selectedFiles().constFirst());
+}
diff --git a/examples/svg/svgviewer/exportdialog.h b/examples/svg/svgviewer/exportdialog.h
new file mode 100644
index 0000000..71d8bdd
--- /dev/null
+++ b/examples/svg/svgviewer/exportdialog.h
@@ -0,0 +1,80 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** You may use this file under the terms of the BSD license as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef EXPORTDIALOG_H
+#define EXPORTDIALOG_H
+
+#include <QDialog>
+
+QT_FORWARD_DECLARE_CLASS(QLineEdit)
+QT_FORWARD_DECLARE_CLASS(QSpinBox)
+
+class ExportDialog : public QDialog
+{
+    Q_OBJECT
+public:
+    explicit ExportDialog(QWidget *parent = 0);
+
+    QSize exportSize() const;
+    void setExportSize(const QSize &);
+
+    QString exportFileName() const;
+    void setExportFileName(const QString &);
+
+    void accept() override;
+
+private slots:
+    void browse();
+    void resetExportSize();
+    void exportWidthChanged(int width);
+    void exportHeightChanged(int height);
+
+private:
+    void setExportWidthBlocked(int width);
+    void setExportHeightBlocked(int height);
+
+    QLineEdit *m_fileNameLineEdit;
+    QSpinBox *m_widthSpinBox;
+    QSpinBox *m_heightSpinBox;
+    QSize m_defaultSize;
+    qreal m_aspectRatio;
+};
+
+#endif // EXPORTDIALOG_H
diff --git a/examples/svg/svgviewer/mainwindow.cpp b/examples/svg/svgviewer/mainwindow.cpp
index 4e94642..c63f223 100644
--- a/examples/svg/svgviewer/mainwindow.cpp
+++ b/examples/svg/svgviewer/mainwindow.cpp
@@ -39,18 +39,35 @@
 ****************************************************************************/
 
 #include "mainwindow.h"
+#include "exportdialog.h"
 
 #include <QtWidgets>
+#include <QSvgRenderer>
 
 #include "svgview.h"
 
+static inline QString picturesLocation()
+{
+    return QStandardPaths::standardLocations(QStandardPaths::PicturesLocation).value(0, QDir::currentPath());
+}
+
 MainWindow::MainWindow()
     : QMainWindow()
     , m_view(new SvgView)
 {
+    QToolBar *toolBar = new QToolBar(this);
+    addToolBar(Qt::TopToolBarArea, toolBar);
+
     QMenu *fileMenu = menuBar()->addMenu(tr("&File"));
-    QAction *openAction = fileMenu->addAction(tr("&Open..."), this, &MainWindow::openFile);
+    const QIcon openIcon = QIcon::fromTheme("document-open", QIcon(":/qt-project.org/styles/commonstyle/images/standardbutton-open-32.png"));
+    QAction *openAction = fileMenu->addAction(openIcon, tr("&Open..."), this, &MainWindow::openFile);
     openAction->setShortcut(QKeySequence::Open);
+    toolBar->addAction(openAction);
+    const QIcon exportIcon = QIcon::fromTheme("document-save", QIcon(":/qt-project.org/styles/commonstyle/images/standardbutton-save-32.png"));
+    QAction *exportAction = fileMenu->addAction(exportIcon, tr("&Export..."), this, &MainWindow::exportImage);
+    exportAction->setToolTip(tr("Export Image"));
+    exportAction->setShortcut(Qt::CTRL + Qt::Key_E);
+    toolBar->addAction(exportAction);
     QAction *quitAction = fileMenu->addAction(tr("E&xit"), qApp, QCoreApplication::quit);
     quitAction->setShortcuts(QKeySequence::Quit);
 
@@ -116,7 +133,7 @@ void MainWindow::openFile()
     fileDialog.setMimeTypeFilters(QStringList() << "image/svg+xml" << "image/svg+xml-compressed");
     fileDialog.setWindowTitle(tr("Open SVG File"));
     if (m_currentPath.isEmpty())
-        fileDialog.setDirectory(QStandardPaths::standardLocations(QStandardPaths::PicturesLocation).value(0, QDir::currentPath()));
+        fileDialog.setDirectory(picturesLocation());
 
     while (fileDialog.exec() == QDialog::Accepted && !loadFile(fileDialog.selectedFiles().constFirst()))
         ;
@@ -126,7 +143,7 @@ bool MainWindow::loadFile(const QString &fileName)
 {
     if (!QFileInfo::exists(fileName) || !m_view->openFile(fileName)) {
         QMessageBox::critical(this, tr("Open SVG File"),
-                              QString("Could not open file '%1'.").arg(QDir::toNativeSeparators(fileName)));
+                              tr("Could not open file '%1'.").arg(QDir::toNativeSeparators(fileName)));
         return false;
     }
 
@@ -154,3 +171,43 @@ void MainWindow::setRenderer(int renderMode)
     m_highQualityAntialiasingAction->setEnabled(renderMode == SvgView::OpenGL);
     m_view->setRenderer(static_cast<SvgView::RendererType>(renderMode));
 }
+
+void MainWindow::exportImage()
+{
+    ExportDialog exportDialog(this);
+    exportDialog.setExportSize(m_view->svgSize());
+    QString fileName;
+    if (m_currentPath.isEmpty()) {
+        fileName = picturesLocation() + QLatin1String("/export.png");
+    } else {
+        const QFileInfo fi(m_currentPath);
+        fileName = fi.absolutePath() + QLatin1Char('/') + fi.baseName() + QLatin1String(".png");
+    }
+    exportDialog.setExportFileName(fileName);
+
+    while (true) {
+        if (exportDialog.exec() != QDialog::Accepted)
+            break;
+
+        const QSize imageSize = exportDialog.exportSize();
+        QImage image(imageSize, QImage::Format_ARGB32);
+        image.fill(Qt::transparent);
+        QPainter painter;
+        painter.begin(&image);
+        m_view->renderer()->render(&painter, QRectF(QPointF(), QSizeF(imageSize)));
+        painter.end();
+
+        const QString fileName = exportDialog.exportFileName();
+        if (image.save(fileName)) {
+
+            const QString message = tr("Exported %1, %2x%3, %4 bytes")
+                .arg(QDir::toNativeSeparators(fileName)).arg(imageSize.width()).arg(imageSize.height())
+                .arg(QFileInfo(fileName).size());
+            statusBar()->showMessage(message);
+            break;
+        } else {
+            QMessageBox::critical(this, tr("Export Image"),
+                                  tr("Could not write file '%1'.").arg(QDir::toNativeSeparators(fileName)));
+        }
+    }
+}
diff --git a/examples/svg/svgviewer/mainwindow.h b/examples/svg/svgviewer/mainwindow.h
index 215f4a6..c0973f9 100644
--- a/examples/svg/svgviewer/mainwindow.h
+++ b/examples/svg/svgviewer/mainwindow.h
@@ -64,6 +64,7 @@ public:
 
 public slots:
     void openFile();
+    void exportImage();
     void setRenderer(int renderMode);
 
 private:
diff --git a/examples/svg/svgviewer/svgview.cpp b/examples/svg/svgviewer/svgview.cpp
index dd9de1a..cbea85d 100644
--- a/examples/svg/svgviewer/svgview.cpp
+++ b/examples/svg/svgviewer/svgview.cpp
@@ -194,3 +194,9 @@ void SvgView::wheelEvent(QWheelEvent *event)
     event->accept();
 }
 
+QSvgRenderer *SvgView::renderer() const
+{
+    if (m_svgItem)
+        return m_svgItem->renderer();
+    return nullptr;
+}
diff --git a/examples/svg/svgviewer/svgview.h b/examples/svg/svgviewer/svgview.h
index 41c0ca5..645fb49 100644
--- a/examples/svg/svgviewer/svgview.h
+++ b/examples/svg/svgviewer/svgview.h
@@ -44,6 +44,8 @@
 #include <QGraphicsView>
 
 QT_BEGIN_NAMESPACE
+class QGraphicsSvgItem;
+class QSvgRenderer;
 class QWheelEvent;
 class QPaintEvent;
 QT_END_NAMESPACE
@@ -62,6 +64,7 @@ public:
     void drawBackground(QPainter *p, const QRectF &rect) override;
 
     QSize svgSize() const;
+    QSvgRenderer *renderer() const;
 
 public slots:
     void setHighQualityAntialiasing(bool highQualityAntialiasing);
@@ -75,7 +78,7 @@ protected:
 private:
     RendererType m_renderer;
 
-    QGraphicsItem *m_svgItem;
+    QGraphicsSvgItem *m_svgItem;
     QGraphicsRectItem *m_backgroundItem;
     QGraphicsRectItem *m_outlineItem;
 
diff --git a/examples/svg/svgviewer/svgviewer.pro b/examples/svg/svgviewer/svgviewer.pro
index 157af4d..6eea56a 100644
--- a/examples/svg/svgviewer/svgviewer.pro
+++ b/examples/svg/svgviewer/svgviewer.pro
@@ -1,9 +1,11 @@
 HEADERS       = mainwindow.h \
-                svgview.h
+                svgview.h \
+                exportdialog.h
 RESOURCES     = svgviewer.qrc
 SOURCES       = main.cpp \
                 mainwindow.cpp \
-                svgview.cpp
+                svgview.cpp \
+                exportdialog.cpp
 QT           += widgets svg
 
 qtHaveModule(opengl): QT += opengl