in-plcae preview not working due to Promise JS error

src/resources/mathjax_preview.js

@@ -13,7 +13,16 @@ if (typeof VPlantUMLServer == 'undefined') {
     VPlantUMLServer = 'http://www.plantuml.com/plantuml';
 }
 
-new QWebChannel(qt.webChannelTransport,
+if (typeof VWebChannelPort == 'undefined') {
+    var VWebChannelPort = '20001';
+}
+
+window.addEventListener('load', function() {
+    var baseUrl = 'ws://localhost:' + VWebChannelPort;
+    var socket = new WebSocket(baseUrl);
+    socket.onopen = function() {
+        console.log('WebSocket connected to ' + baseUrl);
+        new QWebChannel(socket,
             function(channel) {
                 content = channel.objects.content;
 
@@ -22,8 +31,10 @@ new QWebChannel(qt.webChannelTransport,
 
                 channelInitialized = true;
             });
+    }
+});
 
-var timeStamps = new Map();
+var timeStamps = new Object();
 
 var htmlToElement = function(html) {
     var template = document.createElement('template');
@@ -37,7 +48,7 @@ var isEmptyMathJax = function(text) {
 };
 
 var previewMathJax = function(identifier, id, timeStamp, text, isHtml) {
-    timeStamps.set(identifier, timeStamp);
+    timeStamps[identifier] = timeStamp;
 
     if (isEmptyMathJax(text)) {
         content.mathjaxResultReady(identifier, id, timeStamp, 'png', '');
@@ -87,7 +98,7 @@ var previewMathJax = function(identifier, id, timeStamp, text, isHtml) {
 };
 
 var postProcessMathJax = function(identifier, id, timeStamp, container, isBlock) {
-    if (timeStamps.get(identifier) != timeStamp) {
+    if (timeStamps[identifier] != timeStamp) {
         contentDiv.removeChild(container);
         delete container;
         return;

src/resources/mathjax_preview_template.html

@@ -8,7 +8,7 @@
     </style>
 
     <link rel="stylesheet" type="text/css" href="CSS_PLACE_HOLDER">
-    <script src="qrc:/resources/qwebchannel.js"></script>
+    <script src="qrc:///qtwebchannel/qwebchannel.js"></script>
     <!-- EXTRA_PLACE_HOLDER -->
     <script src="JS_PLACE_HOLDER" async></script>
     <script src="qrc:/utils/dom-to-image/dom-to-image.js" defer></script>

src/src.pro

@@ -160,7 +160,8 @@ SOURCES += main.cpp\
     vpreviewpage.cpp \
     vwebview.cpp \
     websocketclientwrapper.cpp \
-    websockettransport.cpp
+    websockettransport.cpp \
+    vmathjaxwebdocument.cpp
 
 HEADERS  += vmainwindow.h \
     vdirectorytree.h \
@@ -305,7 +306,8 @@ HEADERS  += vmainwindow.h \
     vpreviewpage.h \
     vwebview.h \
     websocketclientwrapper.h \
-    websockettransport.h
+    websockettransport.h \
+    vmathjaxwebdocument.h
 
 RESOURCES += \
     vnote.qrc \

src/utils/vutils.cpp

@@ -978,7 +978,7 @@ with 2em, if there are Chinese characters in it, the font will be a mess.
     return templ;
 }
 
-QString VUtils::generateMathJaxPreviewTemplate()
+QString VUtils::generateMathJaxPreviewTemplate(quint16 p_port)
 {
     QString mj = g_config->getMathjaxJavascript();
     QString templ = VNote::generateMathJaxPreviewTemplate();
@@ -1027,6 +1027,8 @@ QString VUtils::generateMathJaxPreviewTemplate()
                  "<script type=\"text/javascript\" src=\"" + VNote::c_plantUMLZopfliJsFile + "\"></script>\n" +
                  "<script>var VPlantUMLServer = '" + g_config->getPlantUMLServer() + "';</script>\n";
 
+    extraFile += "<script>var VWebChannelPort = '" + QString::number(p_port) + "';</script>\n";
+
     templ.replace(HtmlHolder::c_extraHolder, extraFile);
 
     return templ;

src/utils/vutils.h

@@ -206,7 +206,7 @@ public:
     static QString generateSimpleHtmlTemplate(const QString &p_body);
 
     // Generate template for MathJax preview.
-    static QString generateMathJaxPreviewTemplate();
+    static QString generateMathJaxPreviewTemplate(quint16 p_port);
 
     // Get an available file name in @p_directory with base @p_baseFileName.
     // If there already exists a file named @p_baseFileName, try to add sequence

src/vmathjaxpreviewhelper.cpp

@@ -1,11 +1,14 @@
 #include "vmathjaxpreviewhelper.h"
 
-// #include <QWebEngineView>
-// #include <QWebChannel>
+#include <QWebView>
+#include <QWebChannel>
+#include <QWebSocketServer>
 
 #include "utils/vutils.h"
-// #include "vmathjaxwebdocument.h"
+#include "vmathjaxwebdocument.h"
 #include "vconfigmanager.h"
+#include "websocketclientwrapper.h"
+#include "websockettransport.h"
 
 extern VConfigManager *g_config;
 
@@ -14,7 +17,8 @@ VMathJaxPreviewHelper::VMathJaxPreviewHelper(QWidget *p_parentWidget, QObject *p
       m_parentWidget(p_parentWidget),
       m_initialized(false),
       m_nextID(0),
-      // m_webView(NULL),
+      m_webView(NULL),
+      m_channel(nullptr),
       m_webReady(false)
 {
 }
@@ -30,9 +34,8 @@ void VMathJaxPreviewHelper::doInit()
 
     m_initialized = true;
 
-    /*
-    m_webView = new QWebEngineView(m_parentWidget);
-    connect(m_webView, &QWebEngineView::loadFinished,
+    m_webView = new QWebView(m_parentWidget);
+    connect(m_webView, &QWebView::loadFinished,
             this, [this]() {
                 m_webReady = true;
                 for (auto const & it : m_pendingFunc) {
@@ -41,6 +44,7 @@ void VMathJaxPreviewHelper::doInit()
 
                 m_pendingFunc.clear();
             });
+    m_webView->page()->settings()->setAttribute(QWebSettings::DeveloperExtrasEnabled, true);
     m_webView->hide();
     m_webView->setFocusPolicy(Qt::NoFocus);
 
@@ -71,16 +75,14 @@ void VMathJaxPreviewHelper::doInit()
                 emit diagramPreviewResultReady(p_identifier, p_id, p_timeStamp, p_format, ba);
             });
 
-    QWebChannel *channel = new QWebChannel(m_webView);
-    channel->registerObject(QStringLiteral("content"), m_webDoc);
-    m_webView->page()->setWebChannel(channel);
+    quint16 port = 20001;
+    bindToChannel(port, "content", m_webDoc);
 
     // setHtml() will change focus if it is not disabled.
     m_webView->setEnabled(false);
     QUrl baseUrl(QUrl::fromLocalFile(g_config->getDocumentPathOrHomePath() + QDir::separator()));
-    m_webView->setHtml(VUtils::generateMathJaxPreviewTemplate(), baseUrl);
+    m_webView->setHtml(VUtils::generateMathJaxPreviewTemplate(port), baseUrl);
     m_webView->setEnabled(true);
-    */
 }
 
 void VMathJaxPreviewHelper::previewMathJax(int p_identifier,
@@ -90,7 +92,18 @@ void VMathJaxPreviewHelper::previewMathJax(int p_identifier,
 {
     init();
 
-    emit mathjaxPreviewResultReady(p_identifier, p_id, p_timeStamp, "png", "");
+    if (!m_webReady) {
+        auto func = std::bind(&VMathJaxWebDocument::previewMathJax,
+                              m_webDoc,
+                              p_identifier,
+                              p_id,
+                              p_timeStamp,
+                              p_text,
+                              false);
+        m_pendingFunc.append(func);
+    } else {
+        m_webDoc->previewMathJax(p_identifier, p_id, p_timeStamp, p_text, false);
+    }
 }
 
 void VMathJaxPreviewHelper::previewMathJaxFromHtml(int p_identifier,
@@ -100,7 +113,18 @@ void VMathJaxPreviewHelper::previewMathJaxFromHtml(int p_identifier,
 {
     init();
 
-    emit mathjaxPreviewResultReady(p_identifier, p_id, p_timeStamp, "png", "");
+    if (!m_webReady) {
+        auto func = std::bind(&VMathJaxWebDocument::previewMathJax,
+                              m_webDoc,
+                              p_identifier,
+                              p_id,
+                              p_timeStamp,
+                              p_html,
+                              true);
+        m_pendingFunc.append(func);
+    } else {
+        m_webDoc->previewMathJax(p_identifier, p_id, p_timeStamp, p_html, true);
+    }
 }
 
 void VMathJaxPreviewHelper::previewDiagram(int p_identifier,
@@ -111,5 +135,36 @@ void VMathJaxPreviewHelper::previewDiagram(int p_identifier,
 {
     init();
 
-    emit diagramPreviewResultReady(p_identifier, p_id, p_timeStamp, "png", "");
+    if (!m_webReady) {
+        auto func = std::bind(&VMathJaxWebDocument::previewDiagram,
+                              m_webDoc,
+                              p_identifier,
+                              p_id,
+                              p_timeStamp,
+                              p_lang,
+                              p_text);
+        m_pendingFunc.append(func);
+    } else {
+        m_webDoc->previewDiagram(p_identifier, p_id, p_timeStamp, p_lang, p_text);
+    }
+}
+
+void VMathJaxPreviewHelper::bindToChannel(quint16 p_port, const QString &p_name, QObject *p_object)
+{
+    Q_ASSERT(!m_channel);
+    auto server = new QWebSocketServer("Web View for Preview",
+                                       QWebSocketServer::NonSecureMode,
+                                       this);
+    quint16 port = p_port;
+    if (!server->listen(QHostAddress::LocalHost, port)) {
+        qWarning() << "fail to open web socket server on port" << port;
+        delete server;
+        return;
+    }
+
+    auto clientWrapper = new WebSocketClientWrapper(server, this);
+    m_channel = new QWebChannel(this);
+    connect(clientWrapper, &WebSocketClientWrapper::clientConnected,
+            m_channel, &QWebChannel::connectTo);
+    m_channel->registerObject(p_name, p_object);
 }

src/vmathjaxpreviewhelper.h

@@ -7,8 +7,9 @@
 
 #include "vconstants.h"
 
-// class QWebEngineView;
-// class VMathJaxWebDocument;
+class QWebView;
+class QWebChannel;
+class VMathJaxWebDocument;
 class QWidget;
 
 typedef std::function<void(void)> PendingFunc;
@@ -61,15 +62,19 @@ private:
 
     void doInit();
 
+    void bindToChannel(quint16 p_port, const QString &p_name, QObject *p_object);
+
     QWidget *m_parentWidget;
 
     int m_initialized;
 
     int m_nextID;
 
-    // QWebEngineView *m_webView;
+    QWebView *m_webView;
 
-    // VMathJaxWebDocument *m_webDoc;
+    QWebChannel *m_channel;
+
+    VMathJaxWebDocument *m_webDoc;
 
     bool m_webReady;
 

src/vmathjaxwebdocument.cpp

@@ -0,0 +1,54 @@
+#include "vmathjaxwebdocument.h"
+
+#include <QDebug>
+
+VMathJaxWebDocument::VMathJaxWebDocument(QObject *p_parent)
+    : QObject(p_parent)
+{
+}
+
+void VMathJaxWebDocument::previewMathJax(int p_identifier,
+                                         int p_id,
+                                         TimeStamp p_timeStamp,
+                                         const QString &p_text,
+                                         bool p_isHtml)
+{
+    emit requestPreviewMathJax(p_identifier, p_id, p_timeStamp, p_text, p_isHtml);
+}
+
+void VMathJaxWebDocument::mathjaxResultReady(int p_identifier,
+                                             int p_id,
+                                             unsigned long long p_timeStamp,
+                                             const QString &p_format,
+                                             const QString &p_data)
+{
+    emit mathjaxPreviewResultReady(p_identifier, p_id, p_timeStamp, p_format, p_data);
+}
+
+void VMathJaxWebDocument::diagramResultReady(int p_identifier,
+                                             int p_id,
+                                             unsigned long long p_timeStamp,
+                                             const QString &p_format,
+                                             const QString &p_data)
+{
+    emit diagramPreviewResultReady(p_identifier, p_id, p_timeStamp, p_format, p_data);
+}
+
+void VMathJaxWebDocument::previewDiagram(int p_identifier,
+                                         int p_id,
+                                         TimeStamp p_timeStamp,
+                                         const QString &p_lang,
+                                         const QString &p_text)
+{
+    emit requestPreviewDiagram(p_identifier,
+                               p_id,
+                               p_timeStamp,
+                               p_lang,
+                               p_text);
+}
+
+void VMathJaxWebDocument::setLog(const QString &p_log)
+{
+    qDebug() << "JS:" << p_log;
+}
+

src/vmathjaxwebdocument.h

@@ -0,0 +1,69 @@
+#ifndef VMATHJAXWEBDOCUMENT_H
+#define VMATHJAXWEBDOCUMENT_H
+
+#include <QObject>
+
+#include "vconstants.h"
+
+class VMathJaxWebDocument : public QObject
+{
+    Q_OBJECT
+public:
+    explicit VMathJaxWebDocument(QObject *p_parent = nullptr);
+
+    void previewMathJax(int p_identifier,
+                        int p_id,
+                        TimeStamp p_timeStamp,
+                        const QString &p_text,
+                        bool p_isHtml);
+
+    void previewDiagram(int p_identifier,
+                        int p_id,
+                        TimeStamp p_timeStamp,
+                        const QString &p_lang,
+                        const QString &p_text);
+
+public slots:
+    // Will be called in the HTML side
+
+    void mathjaxResultReady(int p_identifier,
+                            int p_id,
+                            unsigned long long p_timeStamp,
+                            const QString &p_format,
+                            const QString &p_data);
+
+    void diagramResultReady(int p_identifier,
+                            int p_id,
+                            unsigned long long p_timeStamp,
+                            const QString &p_format,
+                            const QString &p_data);
+
+    void setLog(const QString &p_log);
+
+signals:
+    void requestPreviewMathJax(int p_identifier,
+                               int p_id,
+                               unsigned long long p_timeStamp,
+                               const QString &p_text,
+                               bool p_isHtml);
+
+    void requestPreviewDiagram(int p_identifier,
+                               int p_id,
+                               unsigned long long p_timeStamp,
+                               const QString &p_lang,
+                               const QString &p_text);
+
+    void mathjaxPreviewResultReady(int p_identifier,
+                                   int p_id,
+                                   TimeStamp p_timeStamp,
+                                   const QString &p_format,
+                                   const QString &p_data);
+
+    void diagramPreviewResultReady(int p_identifier,
+                                   int p_id,
+                                   TimeStamp p_timeStamp,
+                                   const QString &p_format,
+                                   const QString &p_data);
+};
+
+#endif // VMATHJAXWEBDOCUMENT_H