Fixed mouse handling issue when zooming while painting

This also reverts part of e73245b. The
drift was the result of rounding rather than of not taking the viewport
position into account, which is not necessary.

Closes #3863

NEWS.md

@@ -4,6 +4,7 @@
 * tmxrasterizer: Added --hide-object and --show-object arguments (by Lars Luz, #3819)
 * tmxviewer: Added support for viewing JSON maps (#3866)
 * Windows: Fixed the support for WebP images (updated to Qt 6.5.3)
+* Fixed mouse handling issue when zooming while painting (#3863)
 
 ### Tiled 1.10.2 (4 August 2023)
 

src/tiled/mapscene.cpp

@@ -145,6 +145,17 @@ void MapScene::setPainterScale(qreal painterScale)
         mapItem->mapDocument()->renderer()->setPainterScale(painterScale);
 }
 
+void MapScene::setSuppressMouseMoveEvents(bool suppress)
+{
+    mSuppressMouseMoveEvents = suppress;
+
+    if (!suppress && mMouseMoveEventSuppressed) {
+        // Replay the last mouse move event
+        toolMouseMoved(mLastMousePos, mLastModifiers);
+        mMouseMoveEventSuppressed = false;
+    }
+}
+
 /**
  * Returns the bounding rect of the map. This can be different from the
  * sceneRect() when multiple maps are displayed.
@@ -178,12 +189,12 @@ void MapScene::setSelectedTool(AbstractTool *tool)
         if (!mSelectedTool)
             return; // Tool deactivated itself upon activation
 
-        mCurrentModifiers = QApplication::keyboardModifiers();
-        mSelectedTool->modifiersChanged(mCurrentModifiers);
+        mToolModifiers = QApplication::keyboardModifiers();
+        mSelectedTool->modifiersChanged(mToolModifiers);
 
         if (mUnderMouse) {
             mSelectedTool->mouseEntered();
-            mSelectedTool->mouseMoved(mLastMousePos, mCurrentModifiers);
+            mSelectedTool->mouseMoved(mLastMousePos, mToolModifiers);
         }
     }
 }
@@ -469,7 +480,12 @@ void MapScene::keyPressEvent(QKeyEvent *event)
 void MapScene::mouseMoveEvent(QGraphicsSceneMouseEvent *mouseEvent)
 {
     mLastMousePos = mouseEvent->scenePos();
+    mLastModifiers = mouseEvent->modifiers();
 
+    if (mSuppressMouseMoveEvents) {
+        mMouseMoveEventSuppressed = true;
+        return;
+    }
     if (!mMapDocument)
         return;
 
@@ -482,17 +498,8 @@ void MapScene::mouseMoveEvent(QGraphicsSceneMouseEvent *mouseEvent)
 //    if (mouseEvent->isAccepted())
 //        return;
 
-    if (mSelectedTool) {
-        const Qt::KeyboardModifiers newModifiers = mouseEvent->modifiers();
-
-        if (newModifiers != mCurrentModifiers) {
-            mSelectedTool->modifiersChanged(newModifiers);
-            mCurrentModifiers = newModifiers;
-        }
-
-        mSelectedTool->mouseMoved(mouseEvent->scenePos(), mCurrentModifiers);
+    if (toolMouseMoved(mLastMousePos, mLastModifiers))
         mouseEvent->accept();
-    }
 }
 
 void MapScene::mousePressEvent(QGraphicsSceneMouseEvent *mouseEvent)
@@ -621,9 +628,9 @@ bool MapScene::eventFilter(QObject *, QEvent *event)
             QKeyEvent *keyEvent = static_cast<QKeyEvent*>(event);
             const Qt::KeyboardModifiers newModifiers = keyEvent->modifiers();
 
-            if (mSelectedTool && newModifiers != mCurrentModifiers) {
+            if (mSelectedTool && newModifiers != mToolModifiers) {
                 mSelectedTool->modifiersChanged(newModifiers);
-                mCurrentModifiers = newModifiers;
+                mToolModifiers = newModifiers;
             }
         }
         break;
@@ -634,4 +641,18 @@ bool MapScene::eventFilter(QObject *, QEvent *event)
     return false;
 }
 
+bool MapScene::toolMouseMoved(const QPointF &pos, Qt::KeyboardModifiers modifiers)
+{
+    if (!mSelectedTool)
+        return false;
+
+    if (mToolModifiers != modifiers) {
+        mToolModifiers = modifiers;
+        mSelectedTool->modifiersChanged(modifiers);
+    }
+
+    mSelectedTool->mouseMoved(pos, modifiers);
+    return true;
+}
+
 #include "moc_mapscene.cpp"

src/tiled/mapscene.h

@@ -65,6 +65,7 @@ class MapScene : public QGraphicsScene
     void setShowTileCollisionShapes(bool enabled);
     void setParallaxEnabled(bool enabled);
     void setPainterScale(qreal painterScale);
+    void setSuppressMouseMoveEvents(bool suppress);
 
     QRectF mapBoundingRect() const;
 
@@ -127,6 +128,8 @@ class MapScene : public QGraphicsScene
 
     bool eventFilter(QObject *object, QEvent *event) override;
 
+    bool toolMouseMoved(const QPointF &pos, Qt::KeyboardModifiers modifiers);
+
     MapDocument *mMapDocument = nullptr;
     QHash<Map*, MapItem*> mMapItems;
     AbstractTool *mSelectedTool = nullptr;
@@ -135,8 +138,11 @@ class MapScene : public QGraphicsScene
     bool mShowTileCollisionShapes = false;
     bool mParallaxEnabled = true;
     bool mWorldsEnabled = true;
+    bool mSuppressMouseMoveEvents = false;
+    bool mMouseMoveEventSuppressed = false;
     Session::CallbackIterator mEnableWorldsCallback;
-    Qt::KeyboardModifiers mCurrentModifiers = Qt::NoModifier;
+    Qt::KeyboardModifiers mToolModifiers = Qt::NoModifier;
+    Qt::KeyboardModifiers mLastModifiers = Qt::NoModifier;
     QPointF mLastMousePos;
     QRectF mViewRect;
     QColor mDefaultBackgroundColor;

src/tiled/mapview.cpp

@@ -249,7 +249,7 @@ void MapView::updateSceneRect(const QRectF &sceneRect, const QTransform &transfo
 
 void MapView::updateViewRect()
 {
-    const QRectF viewRect = mapToScene(viewport()->geometry()).boundingRect();
+    const QRectF viewRect = mapToScene(viewport()->rect()).boundingRect();
     if (mViewRect == viewRect)
         return;
 
@@ -397,21 +397,21 @@ void MapView::forceCenterOn(QPointF pos)
 
     const qreal width = viewport()->width();
     const qreal height = viewport()->height();
-    const QPointF viewPoint = transform().map(pos) - viewport()->pos();
+    const QPointF viewPoint = transform().map(pos);
 
     if (hScroll) {
         if (isRightToLeft()) {
             qint64 horizontal = 0;
             horizontal += hBar->minimum();
             horizontal += hBar->maximum();
-            horizontal -= int(viewPoint.x() - width / 2.0);
+            horizontal -= qRound(viewPoint.x() - width / 2.0);
             hBar->forceSetValue(static_cast<int>(horizontal));
         } else {
-            hBar->forceSetValue(int(viewPoint.x() - width / 2.0));
+            hBar->forceSetValue(qRound(viewPoint.x() - width / 2.0));
         }
     }
     if (vScroll)
-        vBar->forceSetValue(int(viewPoint.y() - height / 2.0));
+        vBar->forceSetValue(qRound(viewPoint.y() - height / 2.0));
 }
 
 /**
@@ -583,8 +583,13 @@ void MapView::wheelEvent(QWheelEvent *event)
         // No automatic anchoring since we'll do it manually
         setTransformationAnchor(QGraphicsView::NoAnchor);
 
+        // Mouse move events need to be suppressed while zooming, otherwise
+        // the tools will get several mouse move events in various stages of
+        // the zooming process.
+        mapScene()->setSuppressMouseMoveEvents(true);
         mZoomable->handleWheelDelta(event->angleDelta().y());
         adjustCenterFromMousePosition(mLastMousePos);
+        mapScene()->setSuppressMouseMoveEvents(false);
 
         // Restore the centering anchor
         setTransformationAnchor(QGraphicsView::AnchorViewCenter);
@@ -640,7 +645,7 @@ void MapView::adjustCenterFromMousePosition(QPoint mousePos)
 {
     // Place the last known mouse scene pos below the mouse again
     const QWidget *view = viewport();
-    const QPointF viewCenterScenePos = mapToScene(view->geometry().center());
+    const QPointF viewCenterScenePos = viewportTransform().inverted().map(QRectF(view->rect()).center());
     const QPointF mouseScenePos = mapToScene(view->mapFromGlobal(mousePos));
     const QPointF diff = viewCenterScenePos - mouseScenePos;
     QGraphicsView::centerOn(mLastMouseScenePos + diff);