QmlDesigner: Add option for smooth rendering in form editor

Smooth rendering turns on MSAA and doubles the resolution for
rendered items. With this option enabled everything stays smooth when
zooming in. Around factor 8-10 pixels become clearly visible again, but
it still looks relatively smooth.
I added both MSAA and increased the resolution to one option, for simplicity.
The smooth mode takes 4 times the shared memory, which should not
be an issue in most cases.
For now, the option is not the default.

Task-number: QDS-7129
Task-number: QDS-7128
Change-Id: I8a778650bb40f8ba796960db9bc966e8a1efff4e
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>

share/qtcreator/qml/qmlpuppet/qml2puppet/instances/qt5nodeinstanceserver.cpp

@@ -405,6 +405,9 @@ QImage Qt5NodeInstanceServer::grabItem(QQuickItem *item)
     QQuickItemPrivate *pItem = QQuickItemPrivate::get(item);
 
     const bool renderEffects = qEnvironmentVariableIsSet("QMLPUPPET_RENDER_EFFECTS");
+    const bool smoothRendering = qEnvironmentVariableIsSet("QMLPUPPET_SMOOTH_RENDERING");
+
+    int scaleFactor = smoothRendering ? 2 : 1;
 
     if (renderEffects) {
         if (parentEffectItem(item))
@@ -470,6 +473,8 @@ QImage Qt5NodeInstanceServer::grabItem(QQuickItem *item)
         // us to render it to a texture that we can grab to an image.
         QSGRenderContext *rc = QQuickWindowPrivate::get(m_viewData.window.data())->context;
         QSGLayer *layer = rc->sceneGraphContext()->createLayer(rc);
+        if (smoothRendering)
+            layer->setSamples(4);
         layer->setItem(pItem->itemNode());
 
         layer->setRect(QRectF(renderBoundingRect.x(),
@@ -478,8 +483,8 @@ QImage Qt5NodeInstanceServer::grabItem(QQuickItem *item)
                               -renderBoundingRect.height()));
 
         const QSize minSize = rc->sceneGraphContext()->minimumFBOSize();
-        layer->setSize(QSize(qMax(minSize.width(), int(renderBoundingRect.width())),
+        layer->setSize(QSize(qMax(minSize.width(), int(renderBoundingRect.width() * scaleFactor)),
-                             qMax(minSize.height(), int(renderBoundingRect.height()))));
+                             qMax(minSize.height(), int(renderBoundingRect.height() * scaleFactor))));
         layer->scheduleUpdate();
 
         if (layer->updateTexture())
@@ -489,6 +494,8 @@ QImage Qt5NodeInstanceServer::grabItem(QQuickItem *item)
 
         delete layer;
         layer = nullptr;
+
+        renderImage.setDevicePixelRatio(scaleFactor);
     });
 
     m_viewData.renderControl->render();

share/qtcreator/qml/qmlpuppet/qml2puppet/instances/quickitemnodeinstance.cpp

@@ -504,12 +504,12 @@ QImage QuickItemNodeInstance::renderImage() const
     if (s_unifiedRenderPath) {
         renderImage = nodeInstanceServer()->grabWindow();
         renderImage = renderImage.copy(renderBoundingRect.toRect());
+        /* When grabbing an offscren window the device pixel ratio is 1 */
+        renderImage.setDevicePixelRatio(1);
     } else {
         renderImage = nodeInstanceServer()->grabItem(quickItem());
     }
 
-    /* When grabbing an offscren window the device pixel ratio is 1 */
-    renderImage.setDevicePixelRatio(1);
 #endif
 
     return renderImage;

src/plugins/qmldesigner/designercore/instances/puppetcreator.cpp

@@ -504,6 +504,12 @@ QProcessEnvironment PuppetCreator::processEnvironment() const
 #ifndef QMLDESIGNER_TEST
     const QString controlsStyle = m_designerSettings.value(DesignerSettingsKey::
             CONTROLS_STYLE).toString();
+
+    const bool smoothRendering = m_designerSettings.value(DesignerSettingsKey::SMOOTH_RENDERING)
+                                     .toBool();
+
+    if (smoothRendering)
+        environment.set("QMLPUPPET_SMOOTH_RENDERING", "true");
 #else
     const QString controlsStyle;
 #endif

src/plugins/qmldesigner/designersettings.cpp

@@ -82,6 +82,7 @@ void DesignerSettings::fromSettings(QSettings *settings)
     restoreValue(settings, DesignerSettingsKey::ASK_BEFORE_DELETING_ASSET, true);
     const QStringList defaultValue = QStringList() << "#222222" << "#999999";
     restoreValue(settings, DesignerSettingsKey::EDIT3DVIEW_BACKGROUND_COLOR, defaultValue);
+    restoreValue(settings, DesignerSettingsKey::SMOOTH_RENDERING, false);
 
     settings->endGroup();
     settings->endGroup();

src/plugins/qmldesigner/designersettings.h

@@ -72,6 +72,7 @@ const char COLOR_PALETTE_FAVORITE[] = "ColorPaletteFavorite";
 const char ALWAYS_DESIGN_MODE[] = "AlwaysDesignMode";
 const char DISABLE_ITEM_LIBRARY_UPDATE_TIMER[] = "DisableItemLibraryUpdateTimer";
 const char ASK_BEFORE_DELETING_ASSET[] = "AskBeforeDeletingAsset";
+const char SMOOTH_RENDERING[] = "SmoothRendering";
 }
 
 class QMLDESIGNERCORE_EXPORT DesignerSettings : public QHash<QByteArray, QVariant>

src/plugins/qmldesigner/settingspage.cpp

@@ -182,6 +182,7 @@ DesignerSettings SettingsPageWidget::settings() const
                     m_ui.designerAlwaysDesignModeCheckBox->isChecked());
     settings.insert(DesignerSettingsKey::ASK_BEFORE_DELETING_ASSET,
                     m_ui.askBeforeDeletingAssetCheckBox->isChecked());
+    settings.insert(DesignerSettingsKey::SMOOTH_RENDERING, m_ui.smoothRendering->isChecked());
 
     return settings;
 }
@@ -264,6 +265,7 @@ void SettingsPageWidget::setSettings(const DesignerSettings &settings)
     m_ui.emulationGroupBox->setVisible(showAdvancedFeatures);
     m_ui.debugGroupBox->setVisible(showAdvancedFeatures);
     m_ui.featureTimelineEditorCheckBox->setVisible(standaloneMode);
+    m_ui.smoothRendering->setChecked(settings.value(DesignerSettingsKey::SMOOTH_RENDERING).toBool());
 }
 
 void SettingsPageWidget::apply()

src/plugins/qmldesigner/settingspage.ui

@@ -99,6 +99,23 @@
           </property>
          </widget>
         </item>
+        <item row="2" column="1">
+         <widget class="QCheckBox" name="smoothRendering">
+          <property name="toolTip">
+           <string>Enable Smooth Rendering in Form Editor</string>
+          </property>
+          <property name="text">
+           <string/>
+          </property>
+         </widget>
+        </item>
+        <item row="2" column="0">
+         <widget class="QLabel" name="smoothRenderingLabel">
+          <property name="text">
+           <string>Smooth Rendering:</string>
+          </property>
+         </widget>
+        </item>
        </layout>
       </widget>
      </item>