Text to speech engine implementation

PdfForQtLib/PdfForQtLib.pro

@@ -225,7 +225,8 @@ qt_libraries.files =    $$[QT_INSTALL_BINS]/Qt?Widgets$${SUFFIX}.dll \
                         $$[QT_INSTALL_BINS]/Qt?Core$${SUFFIX}.dll \
                         $$[QT_INSTALL_BINS]/Qt?WinExtras$${SUFFIX}.dll \
                         $$[QT_INSTALL_BINS]/Qt?Svg$${SUFFIX}.dll \
-                        $$[QT_INSTALL_BINS]/Qt?PrintSupport$${SUFFIX}.dll
+                        $$[QT_INSTALL_BINS]/Qt?PrintSupport$${SUFFIX}.dll \
+                        $$[QT_INSTALL_BINS]/Qt?TextToSpeech$${SUFFIX}.dll
 qt_libraries.path = $$DESTDIR/install
 INSTALLS += qt_libraries
 
@@ -240,3 +241,8 @@ INSTALLS += qt_plugin_iconengine
 qt_plugin_printsupport.files = $$[QT_INSTALL_PLUGINS]/printsupport/windowsprintersupport$${SUFFIX}.dll
 qt_plugin_printsupport.path = $$DESTDIR/install/printsupport
 INSTALLS += qt_plugin_printsupport
+
+qt_plugin_texttospeech.files = $$[QT_INSTALL_PLUGINS]/texttospeech/qtexttospeech_sapi$${SUFFIX}.dll
+qt_plugin_texttospeech.path = $$DESTDIR/install/texttospeech
+INSTALLS += qt_plugin_texttospeech
+

PdfForQtLib/sources/pdftextlayout.h

@@ -272,7 +272,7 @@ using PDFTextFlows = std::vector<PDFTextFlow>;
 
 /// This class represents a portion of continuous text on the page. It can
 /// consists of multiple blocks (which follow reading order).
-class PDFTextFlow
+class PDFFORQTLIBSHARED_EXPORT PDFTextFlow
 {
 public:
 
@@ -294,6 +294,9 @@ public:
     /// \param expression Regular expression to be matched
     PDFFindResults find(const QRegularExpression& expression) const;
 
+    /// Returns whole text for this text flow
+    QString getText() const { return m_text; }
+
     /// Returns text form character pointers
     /// \param begin Begin character
     /// \param end End character
@@ -327,7 +330,7 @@ private:
 
 /// Text layout of single page. Can handle various fonts, various angles of lines
 /// and vertically oriented text. It performs the "docstrum" algorithm.
-class PDFTextLayout
+class PDFFORQTLIBSHARED_EXPORT PDFTextLayout
 {
 public:
     explicit PDFTextLayout();
@@ -498,4 +501,6 @@ private:
 
 }   // namespace pdf
 
+Q_DECLARE_OPERATORS_FOR_FLAGS(pdf::PDFTextFlow::FlowFlags)
+
 #endif // PDFTEXTLAYOUT_H

PdfForQtLib/sources/pdfutils.h

@@ -445,6 +445,32 @@ inline QColor invertColor(QColor color)
     return QColor::fromRgbF(r, g, b, a);
 }
 
+/// Performs linear interpolation of interval [x1, x2] to interval [y1, y2],
+/// using formula y = y1 + (x - x1) * (y2 - y1) / (x2 - x1), transformed
+/// to formula y = k * x + q, where q = y1 - x1 * k and
+/// k = (y2 - y1) / (x2 - x1).
+template<typename T>
+class PDFLinearInterpolation
+{
+public:
+    constexpr inline PDFLinearInterpolation(T x1, T x2, T y1, T y2) :
+        m_k((y2 - y1) / (x2 - x1)),
+        m_q(y1 - x1 * m_k)
+    {
+
+    }
+
+    /// Maps value from x interval to y interval
+    constexpr inline T operator()(T x) const
+    {
+        return m_k * x + m_q;
+    }
+
+private:
+    T m_k;
+    T m_q;
+};
+
 }   // namespace pdf
 
 #endif // PDFUTILS_H

PdfForQtViewer/PdfForQtViewer.pro

@@ -41,6 +41,7 @@ SOURCES += \
         pdfrendertoimagesdialog.cpp \
         pdfsendmail.cpp \
         pdfsidebarwidget.cpp \
+        pdftexttospeech.cpp \
         pdfviewermainwindow.cpp \
         pdfviewersettings.cpp \
         pdfviewersettingsdialog.cpp \
@@ -54,6 +55,7 @@ HEADERS += \
         pdfrendertoimagesdialog.h \
         pdfsendmail.h \
         pdfsidebarwidget.h \
+        pdftexttospeech.h \
         pdfviewermainwindow.h \
         pdfviewersettings.h \
         pdfviewersettingsdialog.h \

PdfForQtViewer/pdfforqtviewer.qrc

@@ -37,5 +37,8 @@
         <file>resources/rotate-right.svg</file>
         <file>resources/print.svg</file>
         <file>resources/speech.svg</file>
+        <file>resources/pause.svg</file>
+        <file>resources/play.svg</file>
+        <file>resources/stop.svg</file>
     </qresource>
 </RCC>

PdfForQtViewer/pdfsidebarwidget.cpp

@@ -19,6 +19,7 @@
 #include "ui_pdfsidebarwidget.h"
 
 #include "pdfwidgetutils.h"
+#include "pdftexttospeech.h"
 
 #include "pdfdocument.h"
 #include "pdfitemmodels.h"
@@ -40,12 +41,14 @@ constexpr const char* STYLESHEET =
         "QPushButton:disabled { background-color: #404040; color: #000000; }"
         "QPushButton:checked { background-color: #808080; color: #FFFFFF; }"
         "QWidget#thumbnailsToolbarWidget { background-color: #F0F0F0 }"
+        "QWidget#speechPage { background-color: #F0F0F0 }"
         "QWidget#PDFSidebarWidget { background-color: #404040; background: green;}";
 
-PDFSidebarWidget::PDFSidebarWidget(pdf::PDFDrawWidgetProxy* proxy, QWidget* parent) :
+PDFSidebarWidget::PDFSidebarWidget(pdf::PDFDrawWidgetProxy* proxy, PDFTextToSpeech* textToSpeech, QWidget* parent) :
     QWidget(parent),
     ui(new Ui::PDFSidebarWidget),
     m_proxy(proxy),
+    m_textToSpeech(textToSpeech),
     m_outlineTreeModel(nullptr),
     m_thumbnailsModel(nullptr),
     m_optionalContentTreeModel(nullptr),
@@ -93,6 +96,7 @@ PDFSidebarWidget::PDFSidebarWidget(pdf::PDFDrawWidgetProxy* proxy, QWidget* pare
     m_pageInfo[Bookmarks] = { ui->bookmarksButton, ui->bookmarksPage };
     m_pageInfo[Thumbnails] = { ui->thumbnailsButton, ui->thumbnailsPage };
     m_pageInfo[Attachments] = { ui->attachmentsButton, ui->attachmentsPage };
+    m_pageInfo[Speech] = { ui->speechButton, ui->speechPage };
 
     for (const auto& pageInfo : m_pageInfo)
     {
@@ -102,6 +106,10 @@ PDFSidebarWidget::PDFSidebarWidget(pdf::PDFDrawWidgetProxy* proxy, QWidget* pare
         }
     }
 
+    m_textToSpeech->initializeUI(ui->speechLocaleComboBox, ui->speechVoiceComboBox,
+                                 ui->speechRateEdit, ui->speechPitchEdit, ui->speechVolumeEdit,
+                                 ui->speechPlayButton, ui->speechPauseButton, ui->speechStopButton, ui->speechSynchronizeButton);
+
     selectPage(Invalid);
     updateButtons();
 }
@@ -220,6 +228,9 @@ bool PDFSidebarWidget::isEmpty(Page page) const
         case Attachments:
             return m_attachmentsTreeModel->isEmpty();
 
+        case Speech:
+            return !m_textToSpeech->isValid();
+
         default:
             Q_ASSERT(false);
             break;

PdfForQtViewer/pdfsidebarwidget.h

@@ -45,13 +45,14 @@ class PDFOptionalContentTreeItemModel;
 
 namespace pdfviewer
 {
+class PDFTextToSpeech;
 
 class PDFSidebarWidget : public QWidget
 {
     Q_OBJECT
 
 public:
-    explicit PDFSidebarWidget(pdf::PDFDrawWidgetProxy* proxy, QWidget* parent = nullptr);
+    explicit PDFSidebarWidget(pdf::PDFDrawWidgetProxy* proxy, PDFTextToSpeech* textToSpeech, QWidget* parent);
     virtual ~PDFSidebarWidget() override;
 
     virtual void paintEvent(QPaintEvent* event) override;
@@ -64,6 +65,7 @@ public:
         Thumbnails,
         OptionalContent,
         Attachments,
+        Speech,
         _END
     };
 
@@ -105,6 +107,7 @@ private:
 
     Ui::PDFSidebarWidget* ui;
     pdf::PDFDrawWidgetProxy* m_proxy;
+    PDFTextToSpeech* m_textToSpeech;
     pdf::PDFOutlineTreeItemModel* m_outlineTreeModel;
     pdf::PDFThumbnailsItemModel* m_thumbnailsModel;
     pdf::PDFOptionalContentTreeItemModel* m_optionalContentTreeModel;

PdfForQtViewer/pdfsidebarwidget.ui

@@ -80,6 +80,19 @@
        </property>
       </widget>
      </item>
+     <item>
+      <widget class="QPushButton" name="speechButton">
+       <property name="text">
+        <string>Speech</string>
+       </property>
+       <property name="checkable">
+        <bool>true</bool>
+       </property>
+       <property name="flat">
+        <bool>true</bool>
+       </property>
+      </widget>
+     </item>
      <item>
       <spacer name="buttonSpacer">
        <property name="orientation">
@@ -98,7 +111,7 @@
    <item>
     <widget class="QStackedWidget" name="stackedWidget">
      <property name="currentIndex">
-      <number>2</number>
+      <number>5</number>
      </property>
      <widget class="QWidget" name="emptyPage"/>
      <widget class="QWidget" name="bookmarksPage">
@@ -238,6 +251,142 @@
        </item>
       </layout>
      </widget>
+     <widget class="QWidget" name="speechPage">
+      <layout class="QVBoxLayout" name="verticalLayout_2">
+       <item>
+        <widget class="QComboBox" name="speechLocaleComboBox"/>
+       </item>
+       <item>
+        <widget class="QComboBox" name="speechVoiceComboBox"/>
+       </item>
+       <item>
+        <layout class="QGridLayout" name="gridLayout">
+         <item row="0" column="1">
+          <widget class="QSlider" name="speechRateEdit">
+           <property name="minimum">
+            <number>-10</number>
+           </property>
+           <property name="maximum">
+            <number>10</number>
+           </property>
+           <property name="orientation">
+            <enum>Qt::Horizontal</enum>
+           </property>
+          </widget>
+         </item>
+         <item row="2" column="1">
+          <widget class="QSlider" name="speechVolumeEdit">
+           <property name="maximum">
+            <number>100</number>
+           </property>
+           <property name="value">
+            <number>100</number>
+           </property>
+           <property name="orientation">
+            <enum>Qt::Horizontal</enum>
+           </property>
+          </widget>
+         </item>
+         <item row="1" column="1">
+          <widget class="QSlider" name="speechPitchEdit">
+           <property name="minimum">
+            <number>-10</number>
+           </property>
+           <property name="maximum">
+            <number>10</number>
+           </property>
+           <property name="orientation">
+            <enum>Qt::Horizontal</enum>
+           </property>
+          </widget>
+         </item>
+         <item row="0" column="0">
+          <widget class="QLabel" name="speechRateLabel">
+           <property name="text">
+            <string>Rate</string>
+           </property>
+          </widget>
+         </item>
+         <item row="1" column="0">
+          <widget class="QLabel" name="speechPitchLabel">
+           <property name="text">
+            <string>Pitch</string>
+           </property>
+          </widget>
+         </item>
+         <item row="2" column="0">
+          <widget class="QLabel" name="speechVolumeLabel">
+           <property name="text">
+            <string>Volume</string>
+           </property>
+          </widget>
+         </item>
+        </layout>
+       </item>
+       <item>
+        <layout class="QHBoxLayout" name="horizontalLayout">
+         <item>
+          <widget class="QToolButton" name="speechPlayButton">
+           <property name="icon">
+            <iconset resource="pdfforqtviewer.qrc">
+             <normaloff>:/resources/play.svg</normaloff>:/resources/play.svg</iconset>
+           </property>
+          </widget>
+         </item>
+         <item>
+          <widget class="QToolButton" name="speechPauseButton">
+           <property name="icon">
+            <iconset resource="pdfforqtviewer.qrc">
+             <normaloff>:/resources/pause.svg</normaloff>:/resources/pause.svg</iconset>
+           </property>
+          </widget>
+         </item>
+         <item>
+          <widget class="QToolButton" name="speechStopButton">
+           <property name="icon">
+            <iconset resource="pdfforqtviewer.qrc">
+             <normaloff>:/resources/stop.svg</normaloff>:/resources/stop.svg</iconset>
+           </property>
+          </widget>
+         </item>
+         <item>
+          <spacer name="horizontalSpacer">
+           <property name="orientation">
+            <enum>Qt::Horizontal</enum>
+           </property>
+           <property name="sizeHint" stdset="0">
+            <size>
+             <width>40</width>
+             <height>20</height>
+            </size>
+           </property>
+          </spacer>
+         </item>
+         <item>
+          <widget class="QToolButton" name="speechSynchronizeButton">
+           <property name="icon">
+            <iconset resource="pdfforqtviewer.qrc">
+             <normaloff>:/resources/synchronize.svg</normaloff>:/resources/synchronize.svg</iconset>
+           </property>
+          </widget>
+         </item>
+        </layout>
+       </item>
+       <item>
+        <spacer name="verticalSpacer">
+         <property name="orientation">
+          <enum>Qt::Vertical</enum>
+         </property>
+         <property name="sizeHint" stdset="0">
+          <size>
+           <width>20</width>
+           <height>393</height>
+          </size>
+         </property>
+        </spacer>
+       </item>
+      </layout>
+     </widget>
     </widget>
    </item>
   </layout>

PdfForQtViewer/pdftexttospeech.cpp

@@ -0,0 +1,498 @@
+//    Copyright (C) 2020 Jakub Melka
+//
+//    This file is part of PdfForQt.
+//
+//    PdfForQt is free software: you can redistribute it and/or modify
+//    it under the terms of the GNU Lesser General Public License as published by
+//    the Free Software Foundation, either version 3 of the License, or
+//    (at your option) any later version.
+//
+//    PdfForQt is distributed in the hope that it will be useful,
+//    but WITHOUT ANY WARRANTY; without even the implied warranty of
+//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//    GNU Lesser General Public License for more details.
+//
+//    You should have received a copy of the GNU Lesser General Public License
+//    along with PDFForQt.  If not, see <https://www.gnu.org/licenses/>.
+
+#include "pdftexttospeech.h"
+#include "pdfviewersettings.h"
+#include "pdfdrawspacecontroller.h"
+#include "pdfcompiler.h"
+#include "pdfdrawwidget.h"
+
+#include <QAction>
+#include <QSlider>
+#include <QComboBox>
+#include <QToolButton>
+#include <QTextToSpeech>
+
+namespace pdfviewer
+{
+
+PDFTextToSpeech::PDFTextToSpeech(QObject* parent) :
+    BaseClass(parent),
+    m_textToSpeech(nullptr),
+    m_document(nullptr),
+    m_proxy(nullptr),
+    m_state(Invalid),
+    m_initialized(false),
+    m_speechLocaleComboBox(nullptr),
+    m_speechVoiceComboBox(nullptr),
+    m_speechRateEdit(nullptr),
+    m_speechVolumeEdit(nullptr),
+    m_speechPitchEdit(nullptr),
+    m_speechPlayButton(nullptr),
+    m_speechPauseButton(nullptr),
+    m_speechStopButton(nullptr),
+    m_speechSynchronizeButton(nullptr)
+{
+
+}
+
+bool PDFTextToSpeech::isValid() const
+{
+    return m_document != nullptr;
+}
+
+void PDFTextToSpeech::setDocument(const pdf::PDFDocument* document)
+{
+    if (m_document != document)
+    {
+        stop();
+        m_document = document;
+
+        if (m_textToSpeech)
+        {
+            m_state = m_document ? Ready : NoDocument;
+        }
+        else
+        {
+            // Set state to invalid, speech engine is not set
+            m_state = Invalid;
+        }
+
+        updateUI();
+    }
+}
+
+void PDFTextToSpeech::setSettings(const PDFViewerSettings* viewerSettings)
+{
+    Q_ASSERT(viewerSettings);
+
+    if (!m_initialized)
+    {
+        // This object is not initialized yet
+        return;
+    }
+
+    // First, stop the engine
+    stop();
+
+    delete m_textToSpeech;
+    m_textToSpeech = nullptr;
+
+    const PDFViewerSettings::Settings& settings = viewerSettings->getSettings();
+    if (!settings.m_speechEngine.isEmpty())
+    {
+        m_textToSpeech = new QTextToSpeech(settings.m_speechEngine);
+        connect(m_textToSpeech, &QTextToSpeech::stateChanged, this, &PDFTextToSpeech::updatePlay);
+        m_state = m_document ? Ready : NoDocument;
+
+        QVector<QLocale> locales = m_textToSpeech->availableLocales();
+        m_speechLocaleComboBox->setUpdatesEnabled(false);
+        m_speechLocaleComboBox->clear();
+        for (const QLocale& locale : locales)
+        {
+            m_speechLocaleComboBox->addItem(QString("%1 (%2)").arg(locale.nativeLanguageName(), locale.nativeCountryName()), locale.name());
+        }
+        m_speechLocaleComboBox->setUpdatesEnabled(true);
+
+        QVector<QVoice> voices = m_textToSpeech->availableVoices();
+        m_speechVoiceComboBox->setUpdatesEnabled(false);
+        m_speechVoiceComboBox->clear();
+        for (const QVoice& voice : voices)
+        {
+            m_speechVoiceComboBox->addItem(QString("%1 (%2, %3)").arg(voice.name(), QVoice::genderName(voice.gender()), QVoice::ageName(voice.age())), voice.name());
+        }
+        m_speechVoiceComboBox->setUpdatesEnabled(true);
+    }
+    else
+    {
+        // Set state to invalid, speech engine is not set
+        m_state = Invalid;
+
+        m_speechLocaleComboBox->clear();
+        m_speechVoiceComboBox->clear();
+    }
+
+    if (m_textToSpeech)
+    {
+        setLocale(settings.m_speechLocale);
+        setVoice(settings.m_speechVoice);
+        setRate(settings.m_speechRate);
+        setPitch(settings.m_speechPitch);
+        setVolume(settings.m_speechVolume);
+    }
+
+    updateUI();
+}
+
+void PDFTextToSpeech::setProxy(const pdf::PDFDrawWidgetProxy* proxy)
+{
+    m_proxy = proxy;
+    pdf::PDFAsynchronousTextLayoutCompiler* compiler = m_proxy->getTextLayoutCompiler();
+    connect(compiler, &pdf::PDFAsynchronousTextLayoutCompiler::textLayoutChanged, this, &PDFTextToSpeech::updatePlay);
+}
+
+void PDFTextToSpeech::initializeUI(QComboBox* speechLocaleComboBox,
+                                   QComboBox* speechVoiceComboBox,
+                                   QSlider* speechRateEdit,
+                                   QSlider* speechVolumeEdit,
+                                   QSlider* speechPitchEdit,
+                                   QToolButton* speechPlayButton,
+                                   QToolButton* speechPauseButton,
+                                   QToolButton* speechStopButton,
+                                   QToolButton* speechSynchronizeButton)
+{
+    Q_ASSERT(speechLocaleComboBox);
+    Q_ASSERT(speechVoiceComboBox);
+    Q_ASSERT(speechRateEdit);
+    Q_ASSERT(speechVolumeEdit);
+    Q_ASSERT(speechPitchEdit);
+    Q_ASSERT(speechPlayButton);
+    Q_ASSERT(speechPauseButton);
+    Q_ASSERT(speechStopButton);
+    Q_ASSERT(speechSynchronizeButton);
+
+    m_speechLocaleComboBox = speechLocaleComboBox;
+    m_speechVoiceComboBox = speechVoiceComboBox;
+    m_speechRateEdit = speechRateEdit;
+    m_speechVolumeEdit = speechVolumeEdit;
+    m_speechPitchEdit = speechPitchEdit;
+    m_speechPlayButton = speechPlayButton;
+    m_speechPauseButton = speechPauseButton;
+    m_speechStopButton = speechStopButton;
+    m_speechSynchronizeButton = speechSynchronizeButton;
+
+    connect(m_speechLocaleComboBox, QOverload<int>::of(&QComboBox::currentIndexChanged), this, &PDFTextToSpeech::onLocaleChanged);
+    connect(m_speechVoiceComboBox, QOverload<int>::of(&QComboBox::currentIndexChanged), this, &PDFTextToSpeech::onVoiceChanged);
+    connect(m_speechRateEdit, &QSlider::valueChanged, this, &PDFTextToSpeech::onRateChanged);
+    connect(m_speechPitchEdit, &QSlider::valueChanged, this, &PDFTextToSpeech::onPitchChanged);
+    connect(m_speechVolumeEdit, &QSlider::valueChanged, this, &PDFTextToSpeech::onVolumeChanged);
+    connect(m_speechPlayButton, &QToolButton::clicked, this, &PDFTextToSpeech::onPlayClicked);
+    connect(m_speechPauseButton, &QToolButton::clicked, this, &PDFTextToSpeech::onPauseClicked);
+    connect(m_speechStopButton, &QToolButton::clicked, this, &PDFTextToSpeech::onStopClicked);
+
+    m_initialized = true;
+}
+
+void PDFTextToSpeech::updateUI()
+{
+    bool enableControls = false;
+    bool enablePlay = false;
+    bool enablePause = false;
+    bool enableStop = false;
+
+    switch (m_state)
+    {
+        case pdfviewer::PDFTextToSpeech::Invalid:
+        {
+            enableControls = false;
+            enablePlay = false;
+            enablePause = false;
+            enableStop = false;
+            break;
+        }
+
+        case pdfviewer::PDFTextToSpeech::NoDocument:
+        {
+            enableControls = true;
+            enablePlay = false;
+            enablePause = false;
+            enableStop = false;
+            break;
+        }
+
+        case pdfviewer::PDFTextToSpeech::Ready:
+        {
+            enableControls = true;
+            enablePlay = true;
+            enablePause = false;
+            enableStop = false;
+            break;
+        }
+
+        case pdfviewer::PDFTextToSpeech::Playing:
+        {
+            enableControls = true;
+            enablePlay = false;
+            enablePause = true;
+            enableStop = true;
+            break;
+        }
+
+        case pdfviewer::PDFTextToSpeech::Paused:
+        {
+            enableControls = true;
+            enablePlay = true;
+            enablePause = false;
+            enableStop = true;
+            break;
+        }
+
+        case pdfviewer::PDFTextToSpeech::Error:
+        {
+            enableControls = false;
+            enablePlay = false;
+            enablePause = false;
+            enableStop = false;
+            break;
+        }
+
+        default:
+            Q_ASSERT(false);
+            break;
+    }
+
+    m_speechLocaleComboBox->setEnabled(enableControls && m_speechLocaleComboBox->count() > 0);
+    m_speechVoiceComboBox->setEnabled(enableControls && m_speechVoiceComboBox->count() > 0);
+    m_speechRateEdit->setEnabled(enableControls);
+    m_speechVolumeEdit->setEnabled(enableControls);
+    m_speechPitchEdit->setEnabled(enableControls);
+    m_speechPlayButton->setEnabled(enablePlay);
+    m_speechPauseButton->setEnabled(enablePause);
+    m_speechStopButton->setEnabled(enableStop);
+    m_speechSynchronizeButton->setEnabled(enableControls);
+}
+
+void PDFTextToSpeech::stop()
+{
+    switch (m_state)
+    {
+        case Playing:
+        case Paused:
+        {
+            m_textToSpeech->stop();
+            m_currentTextFlowIndex = 0;
+            m_currentPage = 0;
+            m_currentTextLayout = pdf::PDFTextLayout();
+            m_textFlows = pdf::PDFTextFlows();
+            m_state = Ready;
+            break;
+        }
+
+        default:
+            break;
+    }
+
+    updateUI();
+}
+
+void PDFTextToSpeech::setLocale(const QString& locale)
+{
+    m_speechLocaleComboBox->setCurrentIndex(m_speechLocaleComboBox->findData(locale));
+}
+
+void PDFTextToSpeech::setVoice(const QString& voice)
+{
+    m_speechVoiceComboBox->setCurrentIndex(m_speechVoiceComboBox->findData(voice));
+}
+
+void PDFTextToSpeech::setRate(const double rate)
+{
+    pdf::PDFLinearInterpolation<double> interpolation(-1.0, 1.0, m_speechRateEdit->minimum(), m_speechRateEdit->maximum());
+    m_speechRateEdit->setValue(qRound(interpolation(rate)));
+}
+
+void PDFTextToSpeech::setPitch(const double pitch)
+{
+    pdf::PDFLinearInterpolation<double> interpolation(-1.0, 1.0, m_speechPitchEdit->minimum(), m_speechPitchEdit->maximum());
+    m_speechPitchEdit->setValue(qRound(interpolation(pitch)));
+}
+
+void PDFTextToSpeech::setVolume(const double volume)
+{
+    pdf::PDFLinearInterpolation<double> interpolation(0.0, 1.0, m_speechVolumeEdit->minimum(), m_speechVolumeEdit->maximum());
+    m_speechVolumeEdit->setValue(qRound(interpolation(volume)));
+}
+
+void PDFTextToSpeech::onLocaleChanged()
+{
+    if (m_textToSpeech)
+    {
+        m_textToSpeech->setLocale(QLocale(m_speechLocaleComboBox->currentData().toString()));
+    }
+}
+
+void PDFTextToSpeech::onVoiceChanged()
+{
+    if (m_textToSpeech)
+    {
+        QString voice = m_speechVoiceComboBox->currentData().toString();
+        for (const QVoice& voiceObject : m_textToSpeech->availableVoices())
+        {
+            if (voiceObject.name() == voice)
+            {
+                m_textToSpeech->setVoice(voiceObject);
+            }
+        }
+    }
+}
+
+void PDFTextToSpeech::onRateChanged(int rate)
+{
+    if (m_textToSpeech)
+    {
+        pdf::PDFLinearInterpolation<double> interpolation(m_speechRateEdit->minimum(), m_speechRateEdit->maximum(), -1.0, 1.0);
+        m_textToSpeech->setRate(interpolation(rate));
+    }
+}
+
+void PDFTextToSpeech::onPitchChanged(int pitch)
+{
+    if (m_textToSpeech)
+    {
+        pdf::PDFLinearInterpolation<double> interpolation(m_speechPitchEdit->minimum(), m_speechPitchEdit->maximum(), -1.0, 1.0);
+        m_textToSpeech->setPitch(interpolation(pitch));
+    }
+}
+
+void PDFTextToSpeech::onVolumeChanged(int volume)
+{
+    if (m_textToSpeech)
+    {
+        pdf::PDFLinearInterpolation<double> interpolation(m_speechVolumeEdit->minimum(), m_speechVolumeEdit->maximum(), 0.0, 1.0);
+        m_textToSpeech->setVolume(interpolation(volume));
+    }
+}
+
+void PDFTextToSpeech::onPlayClicked()
+{
+    switch (m_state)
+    {
+        case Paused:
+        {
+            m_textToSpeech->resume();
+            m_state = Playing;
+            updatePlay();
+            break;
+        }
+
+        case Ready:
+        {
+            m_state = Playing;
+            m_currentTextFlowIndex = std::numeric_limits<size_t>::max();
+            m_currentPage = -1;
+            updatePlay();
+            break;
+        }
+    }
+
+    updateUI();
+}
+
+void PDFTextToSpeech::onPauseClicked()
+{
+    Q_ASSERT(m_state == Playing);
+
+    if (m_state == Playing)
+    {
+        m_textToSpeech->pause();
+        m_state = Paused;
+        updateUI();
+    }
+}
+
+void PDFTextToSpeech::onStopClicked()
+{
+    stop();
+}
+
+void PDFTextToSpeech::updatePlay()
+{
+    if (m_state != Playing)
+    {
+        return;
+    }
+
+    Q_ASSERT(m_proxy);
+    Q_ASSERT(m_document);
+
+    // Jakub Melka: Check, if we have text layout. If not, then create it and return immediately.
+    // Otherwise, check, if we have something to say.
+    pdf::PDFAsynchronousTextLayoutCompiler* compiler = m_proxy->getTextLayoutCompiler();
+    if (!compiler->isTextLayoutReady())
+    {
+        compiler->makeTextLayout();
+        return;
+    }
+
+    QTextToSpeech::State state = m_textToSpeech->state();
+    if (state == QTextToSpeech::Ready)
+    {
+        if (m_currentPage == -1)
+        {
+            // Handle starting of document reading
+            std::vector<pdf::PDFInteger> currentPages = m_proxy->getWidget()->getDrawWidget()->getCurrentPages();
+            if (!currentPages.empty())
+            {
+                updateToNextPage(currentPages.front());
+            }
+        }
+        else if (++m_currentTextFlowIndex >= m_textFlows.size())
+        {
+            // Handle transition to next page
+            updateToNextPage(m_currentPage + 1);
+        }
+
+        if (m_currentTextFlowIndex < m_textFlows.size())
+        {
+            // Say next thing
+            const pdf::PDFTextFlow& textFlow = m_textFlows[m_currentTextFlowIndex];
+            QString text = textFlow.getText();
+            m_textToSpeech->say(text);
+        }
+        else
+        {
+            // We are finished the reading
+            m_state = Ready;
+        }
+    }
+    else if (state == QTextToSpeech::BackendError)
+    {
+        m_state = Error;
+    }
+
+    updateUI();
+}
+
+void PDFTextToSpeech::updateToNextPage(pdf::PDFInteger pageIndex)
+{
+    Q_ASSERT(m_document);
+    Q_ASSERT(m_state = Playing);
+
+    m_currentPage = pageIndex;
+    const pdf::PDFInteger pageCount = m_document->getCatalog()->getPageCount();
+
+    pdf::PDFAsynchronousTextLayoutCompiler* compiler = m_proxy->getTextLayoutCompiler();
+    Q_ASSERT(compiler->isTextLayoutReady());
+
+    // Find first nonempty page
+    while (m_currentPage < pageCount)
+    {
+        m_currentTextLayout = compiler->getTextLayout(m_currentPage);
+        m_textFlows = pdf::PDFTextFlow::createTextFlows(m_currentTextLayout, pdf::PDFTextFlow::SeparateBlocks | pdf::PDFTextFlow::RemoveSoftHyphen, m_currentPage);
+
+        if (!m_textFlows.empty())
+        {
+            break;
+        }
+
+        ++m_currentPage;
+    }
+
+    m_currentTextFlowIndex = 0;
+}
+
+}   // namespace pdfviewer

PdfForQtViewer/pdftexttospeech.h

@@ -0,0 +1,136 @@
+//    Copyright (C) 2020 Jakub Melka
+//
+//    This file is part of PdfForQt.
+//
+//    PdfForQt is free software: you can redistribute it and/or modify
+//    it under the terms of the GNU Lesser General Public License as published by
+//    the Free Software Foundation, either version 3 of the License, or
+//    (at your option) any later version.
+//
+//    PdfForQt is distributed in the hope that it will be useful,
+//    but WITHOUT ANY WARRANTY; without even the implied warranty of
+//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//    GNU Lesser General Public License for more details.
+//
+//    You should have received a copy of the GNU Lesser General Public License
+//    along with PDFForQt.  If not, see <https://www.gnu.org/licenses/>.
+
+
+#ifndef PDFTEXTTOSPEECH_H
+#define PDFTEXTTOSPEECH_H
+
+#include "pdftextlayout.h"
+
+#include <QObject>
+
+class QSlider;
+class QComboBox;
+class QToolButton;
+class QTextToSpeech;
+
+namespace pdf
+{
+class PDFDocument;
+class PDFDrawWidgetProxy;
+}
+
+namespace pdfviewer
+{
+class PDFViewerSettings;
+
+/// Text to speech engine used to reading the document
+class PDFTextToSpeech : public QObject
+{
+    Q_OBJECT
+
+private:
+    using BaseClass = QObject;
+
+public:
+    explicit PDFTextToSpeech(QObject* parent);
+
+    enum State
+    {
+        Invalid,    ///< Text to speech engine is invalid (maybe bad engine)
+        NoDocument, ///< No document to read
+        Ready,      ///< Ready to read the document contents
+        Playing,    ///< Document is being read
+        Paused,     ///< User paused the reading
+        Error       ///< Error occured in text to speech engine
+    };
+
+    /// Returns true, if text to speech engine is valid and can be used
+    /// to synthetise text.
+    bool isValid() const;
+
+    /// Sets active document to text to speech engine
+    void setDocument(const pdf::PDFDocument* document);
+
+    /// Apply settings to the reader
+    void setSettings(const PDFViewerSettings* viewerSettings);
+
+    /// Set draw proxy
+    void setProxy(const pdf::PDFDrawWidgetProxy* proxy);
+
+    /// Initialize the ui, which is used
+    void initializeUI(QComboBox* speechLocaleComboBox,
+                      QComboBox* speechVoiceComboBox,
+                      QSlider* speechRateEdit,
+                      QSlider* speechVolumeEdit,
+                      QSlider* speechPitchEdit,
+                      QToolButton* speechPlayButton,
+                      QToolButton* speechPauseButton,
+                      QToolButton* speechStopButton,
+                      QToolButton* speechSynchronizeButton);
+
+private:
+    /// Updates UI controls depending on the state
+    void updateUI();
+
+    /// Stop the engine, if it is reading
+    void stop();
+
+    void setLocale(const QString& locale);
+    void setVoice(const QString& voice);
+    void setRate(const double rate);
+    void setPitch(const double pitch);
+    void setVolume(const double volume);
+
+    void onLocaleChanged();
+    void onVoiceChanged();
+    void onRateChanged(int rate);
+    void onPitchChanged(int pitch);
+    void onVolumeChanged(int volume);
+
+    void onPlayClicked();
+    void onPauseClicked();
+    void onStopClicked();
+
+    void updatePlay();
+    void updateToNextPage(pdf::PDFInteger pageIndex);
+
+    QTextToSpeech* m_textToSpeech;
+    const pdf::PDFDocument* m_document;
+    const pdf::PDFDrawWidgetProxy* m_proxy;
+    State m_state;
+    bool m_initialized;
+
+    QComboBox* m_speechLocaleComboBox;
+    QComboBox* m_speechVoiceComboBox;
+    QSlider* m_speechRateEdit;
+    QSlider* m_speechVolumeEdit;
+    QSlider* m_speechPitchEdit;
+    QToolButton* m_speechPlayButton;
+    QToolButton* m_speechPauseButton;
+    QToolButton* m_speechStopButton;
+    QToolButton* m_speechSynchronizeButton;
+
+    pdf::PDFTextLayout m_currentTextLayout; ///< Text layout for actual page
+    pdf::PDFTextFlows m_textFlows; ///< Text flows for actual page
+    size_t m_currentTextFlowIndex = 0; ///< Index of current text flow
+    pdf::PDFInteger m_currentPage = 0; ///< Current page
+};
+
+}   // namespace pdfviewer
+
+#endif // PDFTEXTTOSPEECH_H

PdfForQtViewer/pdfviewermainwindow.cpp

@@ -88,7 +88,8 @@ PDFViewerMainWindow::PDFViewerMainWindow(QWidget* parent) :
     m_progressDialog(nullptr),
     m_isBusy(false),
     m_isChangingProgressStep(false),
-    m_toolManager(nullptr)
+    m_toolManager(nullptr),
+    m_textToSpeech(new PDFTextToSpeech(this))
 {
     ui->setupUi(this);
 
@@ -199,8 +200,9 @@ PDFViewerMainWindow::PDFViewerMainWindow(QWidget* parent) :
     setFocusProxy(m_pdfWidget);
     m_pdfWidget->updateCacheLimits(m_settings->getCompiledPageCacheLimit() * 1024, m_settings->getThumbnailsCacheLimit(), m_settings->getFontCacheLimit(), m_settings->getInstancedFontCacheLimit());
     m_pdfWidget->getDrawWidgetProxy()->setProgress(m_progress);
+    m_textToSpeech->setProxy(m_pdfWidget->getDrawWidgetProxy());
 
-    m_sidebarWidget = new PDFSidebarWidget(m_pdfWidget->getDrawWidgetProxy(), this);
+    m_sidebarWidget = new PDFSidebarWidget(m_pdfWidget->getDrawWidgetProxy(), m_textToSpeech, this);
     m_sidebarDockWidget = new QDockWidget(tr("Sidebar"), this);
     m_sidebarDockWidget->setObjectName("SidebarDockWidget");
     m_sidebarDockWidget->setAllowedAreas(Qt::LeftDockWidgetArea | Qt::RightDockWidgetArea);
@@ -208,6 +210,7 @@ PDFViewerMainWindow::PDFViewerMainWindow(QWidget* parent) :
     addDockWidget(Qt::LeftDockWidgetArea, m_sidebarDockWidget);
     m_sidebarDockWidget->hide();
     connect(m_sidebarWidget, &PDFSidebarWidget::actionTriggered, this, &PDFViewerMainWindow::onActionTriggered);
+    m_textToSpeech->setSettings(m_settings);
 
     m_advancedFindWidget = new PDFAdvancedFindWidget(m_pdfWidget->getDrawWidgetProxy(), this);
     m_advancedFindDockWidget = new QDockWidget(tr("Advanced find"), this);
@@ -648,6 +651,7 @@ void PDFViewerMainWindow::readSettings()
 
     m_settings->readSettings(settings, m_CMSManager->getDefaultSettings());
     m_CMSManager->setSettings(m_settings->getColorManagementSystemSettings());
+    m_textToSpeech->setSettings(m_settings);
 }
 
 void PDFViewerMainWindow::readActionSettings()
@@ -956,6 +960,7 @@ void PDFViewerMainWindow::setDocument(const pdf::PDFDocument* document)
     }
 
     m_toolManager->setDocument(document);
+    m_textToSpeech->setDocument(document);
     m_pdfWidget->setDocument(document, m_optionalContentActivity);
     m_sidebarWidget->setDocument(document, m_optionalContentActivity);
     m_advancedFindWidget->setDocument(document);
@@ -1130,6 +1135,7 @@ void PDFViewerMainWindow::on_actionOptions_triggered()
         m_settings->setColorManagementSystemSettings(dialog.getCMSSettings());
         m_CMSManager->setSettings(m_settings->getColorManagementSystemSettings());
         m_recentFileManager->setRecentFilesLimit(dialog.getOtherSettings().maximumRecentFileCount);
+        m_textToSpeech->setSettings(m_settings);
     }
 }
 

PdfForQtViewer/pdfviewermainwindow.h

@@ -27,6 +27,7 @@
 #include "pdfdocumentpropertiesdialog.h"
 #include "pdfwidgettool.h"
 #include "pdfrecentfilemanager.h"
+#include "pdftexttospeech.h"
 
 #include <QFuture>
 #include <QTreeView>
@@ -177,6 +178,7 @@ private:
     bool m_isChangingProgressStep;
 
     pdf::PDFToolManager* m_toolManager;
+    PDFTextToSpeech* m_textToSpeech;
 };
 
 }   // namespace pdfviewer

PdfForQtViewer/resources/pause.svg

@@ -0,0 +1,93 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Created with Inkscape (http://www.inkscape.org/) -->
+
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
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+   viewBox="0 0 30 30"
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PdfForQtViewer/resources/play.svg

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+
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+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
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+   height="30mm"
+   viewBox="0 0 30 30"
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+   inkscape:version="0.92.4 (5da689c313, 2019-01-14)"
+   sodipodi:docname="play.svg">
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+     pagecolor="#ffffff"
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PdfForQtViewer/resources/stop.svg

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+   inkscape:version="0.92.4 (5da689c313, 2019-01-14)"
+   sodipodi:docname="stop.svg">
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