Add workaround for TextEdit not rerendering after image loaded

fixes #541

resources/qml/MatrixText.qml

@@ -7,6 +7,7 @@ import QtQuick.Controls 2.3
 import im.nheko 1.0
 
 TextEdit {
+    id: r
     textFormat: TextEdit.RichText
     readOnly: true
     focus: false
@@ -24,4 +25,8 @@ TextEdit {
         cursorShape: hoveredLink ? Qt.PointingHandCursor : Qt.ArrowCursor
     }
 
+    Component.onCompleted: {
+        TimelineManager.fixImageRendering(r.textDocument, r)
+    }
+
 }

src/timeline/TimelineViewManager.cpp

@@ -681,3 +681,13 @@ TimelineViewManager::forwardMessageToRoom(mtx::events::collections::TimelineEven
           },
           *e);
 }
+
+//! WORKAROUND(Nico): for https://bugreports.qt.io/browse/QTBUG-93281
+void
+TimelineViewManager::fixImageRendering(QQuickTextDocument *t, QQuickItem *i)
+{
+        if (t) {
+                QObject::connect(
+                  t->textDocument(), SIGNAL(imagesLoaded()), i, SLOT(updateWholeDocument()));
+        }
+}

src/timeline/TimelineViewManager.h

@@ -5,6 +5,8 @@
 #pragma once
 
 #include <QHash>
+#include <QQuickItem>
+#include <QQuickTextDocument>
 #include <QQuickView>
 #include <QQuickWidget>
 #include <QSharedPointer>
@@ -68,6 +70,8 @@ public:
         Q_INVOKABLE void openLeaveRoomDialog(QString roomid) const;
         Q_INVOKABLE void removeVerificationFlow(DeviceVerificationFlow *flow);
 
+        Q_INVOKABLE void fixImageRendering(QQuickTextDocument *t, QQuickItem *i);
+
         void verifyUser(QString userid);
         void verifyDevice(QString userid, QString deviceid);