QmlDesigner: Fix corrupted preview images in material editor/browser

Now a default preview image is shown if real preview is not yet
available.

Fixes: QDS-7055
Change-Id: Ia2f9ee3aa3b29f49224b6ba8ae8f22f1b36f629a
Reviewed-by: Mahmoud Badri <mahmoud.badri@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Samuel Ghinet <samuel.ghinet@qt.io>

src/plugins/qmldesigner/CMakeLists.txt

@@ -320,6 +320,7 @@ extend_qtc_plugin(QmlDesigner
     materialeditorqmlbackend.cpp materialeditorqmlbackend.h
     materialeditortransaction.cpp materialeditortransaction.h
     materialeditorview.cpp materialeditorview.h
+    materialeditor.qrc
 )
 
 extend_qtc_plugin(QmlDesigner

src/plugins/qmldesigner/components/materialbrowser/materialbrowserwidget.cpp

@@ -81,11 +81,15 @@ public:
     {
         Q_UNUSED(requestedSize)
 
+        static QPixmap defaultPreview = QPixmap::fromImage(QImage(":/materialeditor/images/defaultmaterialpreview.png"));
+
         QPixmap pixmap{150, 150};
 
         qint32 internalId = id.toInt();
         if (m_pixmaps.contains(internalId))
             pixmap = m_pixmaps.value(internalId);
+        else
+            pixmap = defaultPreview;
 
         if (size)
             *size = pixmap.size();

src/plugins/qmldesigner/components/materialeditor/materialeditor.qrc

@@ -0,0 +1,5 @@
+<RCC>
+    <qresource prefix="/materialeditor">
+        <file>images/defaultmaterialpreview.png</file>
+    </qresource>
+</RCC>

src/plugins/qmldesigner/components/materialeditor/materialeditorqmlbackend.cpp

@@ -77,16 +77,21 @@ public:
     {
         Q_UNUSED(requestedSize)
 
+        static QPixmap defaultPreview = QPixmap::fromImage(QImage(":/materialeditor/images/defaultmaterialpreview.png"));
+
         QPixmap pixmap{150, 150};
 
         if (id == "preview") {
             if (!m_previewPixmap.isNull())
                 pixmap = m_previewPixmap;
+            else
+                pixmap = defaultPreview;
         } else {
-            QString path = Core::ICore::resourcePath("qmldesigner/materialEditorQmlSources/images/" + id).toString();
-            pixmap = QPixmap{path};
+            qWarning() << __FUNCTION__ << "Unsupported image id:" << id;
+            pixmap.fill(Qt::red);
         }
 
+
         if (size)
             *size = pixmap.size();
 

src/plugins/qmldesigner/qmldesignerplugin.qbs

@@ -693,6 +693,7 @@ Project {
                 "materialeditor/materialeditortransaction.h",
                 "materialeditor/materialeditorview.cpp",
                 "materialeditor/materialeditorview.h",
+                "materialeditor/materialeditor.qrc",
                 "navigator/iconcheckboxitemdelegate.cpp",
                 "navigator/iconcheckboxitemdelegate.h",
                 "navigator/nameitemdelegate.cpp",