iss-1897 - Fix view rotation effects affects various view handles

The code getViewScaleInverse assumes the m11 value is a scaling matrix but that's not guaranteed! We see the problem occur when the view has been rotated, which changes the matrix type so that it's no longer a pure scale factor. The fix is to create a new scaling matrix from the mScaling property and inverse that instead.
MrStevns · Jan 2, 2025 · d5064f1 · d5064f1
1 parent b6c8b3a
commit d5064f1
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Showing 5 changed files with 12 additions and 6 deletions.
diff --git a/core_lib/src/interface/editor.cpp b/core_lib/src/interface/editor.cpp
@@ -436,7 +436,7 @@ LayerVisibility Editor::layerVisibility()
 
 qreal Editor::viewScaleInversed()
 {
-    return view()->getViewScaleInverse();
+    return view()->getScaleInversed();
 }
 
 void Editor::increaseLayerVisibilityIndex()

diff --git a/core_lib/src/interface/scribblearea.cpp b/core_lib/src/interface/scribblearea.cpp
@@ -1080,7 +1080,7 @@ void ScribbleArea::prepCameraPainter(int frame)
                                   mEditor->playback()->isPlaying(),
                                   mLayerVisibility,
                                   mPrefs->getFloat(SETTING::LAYER_VISIBILITY_THRESHOLD),
-                                  mEditor->view()->getViewScaleInverse());
+                                  mEditor->view()->getScaleInversed());
 
     OnionSkinPainterOptions onionSkinOptions;
     onionSkinOptions.enabledWhilePlaying = mPrefs->getInt(SETTING::ONION_WHILE_PLAYBACK);

diff --git a/core_lib/src/managers/viewmanager.cpp b/core_lib/src/managers/viewmanager.cpp
@@ -108,9 +108,9 @@ QTransform ViewManager::getViewInverse() const
     return mViewCanvasInverse;
 }
 
-qreal ViewManager::getViewScaleInverse() const
+qreal ViewManager::getScaleInversed() const
 {
-    return mViewCanvasInverse.m11();
+    return QTransform::fromScale(mScaling, mScaling).inverted().m11();
 }
 
 void ViewManager::updateViewTransforms()

diff --git a/core_lib/src/managers/viewmanager.h b/core_lib/src/managers/viewmanager.h
@@ -36,7 +36,13 @@ class ViewManager : public BaseManager
 
     QTransform getView() const;
     QTransform getViewInverse() const;
-    qreal getViewScaleInverse() const;
+
+    /**
+     * Creates a scaling matrix based on the current view scale and returns the inverted value
+     * @return The inverted scale value
+     */
+    qreal getScaleInversed() const;
+
     void resetView();
 
     QPointF mapCanvasToScreen(QPointF p) const;

diff --git a/core_lib/src/tool/cameratool.cpp b/core_lib/src/tool/cameratool.cpp
@@ -81,7 +81,7 @@ void CameraTool::updateUIAssists(const Layer* layer)
 
     Camera* cam = camLayer->getLastCameraAtFrame(mEditor->currentFrame(), 0);
     if (cam) {
-        mRotationHandlePoint = localRotationHandlePoint(cameraRect.topLeft(), localCamT, cam->scaling(), mEditor->view()->getViewScaleInverse());
+        mRotationHandlePoint = localRotationHandlePoint(cameraRect.topLeft(), localCamT, cam->scaling(), mEditor->view()->getScaleInversed());
     }
 }