fix: Restore camera rotation and stabilize UI element scaling

Co-authored-by: aider (gemini/gemini-2.5-pro) <aider@aider.chat>

src/Camera.cpp

@@ -87,17 +87,7 @@ void Camera::wheelEvent(QWheelEvent* event, const QVector3D& worldPos)
 QMatrix4x4 Camera::modelViewMatrix() const
 {
     QMatrix4x4 model;
-    float effectiveZoom = m_zoom;
+    model.translate(m_panX, m_panY, m_zoom);
-
-    if (m_isRotating) {
-        QMatrix4x4 rotation;
-        rotation.rotate(m_xRot / 16.0f, 1, 0, 0);
-        rotation.rotate(m_yRot / 16.0f, 0, 1, 0);
-        QVector3D p_rotated = rotation.map(m_rotationPivot);
-        effectiveZoom += (p_rotated - m_rotationPivot).z();
-    }
-
-    model.translate(m_panX, m_panY, effectiveZoom);
 
     if (m_isRotating) {
         model.translate(m_rotationPivot);
@@ -237,6 +227,7 @@ void Camera::animateToPlaneView(int plane)
 void Camera::startRotation(const QVector3D& pivot)
 {
     m_rotationPivot = pivot;
+    m_stableZoom = m_zoom;
 
     QMatrix4x4 rotation;
     rotation.rotate(m_xRot / 16.0f, 1, 0, 0);
@@ -247,6 +238,7 @@ void Camera::startRotation(const QVector3D& pivot)
 
     setPanX(m_panX + p_diff.x());
     setPanY(m_panY + p_diff.y());
+    setZoom(m_zoom + p_diff.z());
 
     m_isRotating = true;
 }
@@ -266,6 +258,7 @@ void Camera::stopRotation()
 
     setPanX(m_panX - p_diff.x());
     setPanY(m_panY - p_diff.y());
+    setZoom(m_zoom - p_diff.z());
 
     m_isRotating = false;
 }
@@ -313,3 +306,11 @@ void Camera::animateRestoreState()
 
     animGroup->start(QAbstractAnimation::DeleteWhenStopped);
 }
+
+float Camera::uiCameraDistance() const
+{
+    if (m_isRotating) {
+        return m_stableZoom;
+    }
+    return m_zoom;
+}

src/Camera.h

@@ -46,6 +46,7 @@ public:
     void stopRotation();
     bool isRotating() const { return m_isRotating; }
     const QVector3D& rotationPivot() const { return m_rotationPivot; }
+    float uiCameraDistance() const;
 
     float savedXRot() const { return m_savedXRot; }
     float savedYRot() const { return m_savedYRot; }
@@ -67,6 +68,7 @@ private:
 
     QVector3D m_rotationPivot;
     bool m_isRotating = false;
+    float m_stableZoom = 0;
 
     float m_savedXRot = 0;
     float m_savedYRot = 0;

src/SketchGrid.cpp

@@ -72,7 +72,7 @@ void SketchGrid::paintGL(SketchPlane plane, QOpenGLShaderProgram* shaderProgram,
 
 void SketchGrid::drawGridLines(SketchPlane plane, QOpenGLShaderProgram* shaderProgram, int colorLoc)
 {
-    auto params = getGridParams(-m_viewport->camera()->zoom());
+    auto params = getGridParams(-m_viewport->camera()->uiCameraDistance());
     const float minorIncrement = params.minorIncrement;
     const int gridSize = params.gridSize;
 
@@ -115,7 +115,7 @@ void SketchGrid::drawGridLines(SketchPlane plane, QOpenGLShaderProgram* shaderPr
 
 void SketchGrid::drawAxes(SketchPlane plane, QOpenGLShaderProgram* shaderProgram, int colorLoc)
 {
-    auto params = getGridParams(-m_viewport->camera()->zoom());
+    auto params = getGridParams(-m_viewport->camera()->uiCameraDistance());
     const int axisLength = params.gridSize;
     QVector<GLfloat> vertices;
 
@@ -161,7 +161,7 @@ void SketchGrid::paintAxisLabels(QPainter& painter, SketchGrid::SketchPlane plan
     painter.setPen(Qt::white);
     painter.setFont(QFont("Arial", 10));
 
-    auto params = getGridParams(-m_viewport->camera()->zoom());
+    auto params = getGridParams(-m_viewport->camera()->uiCameraDistance());
     const float majorIncrement = params.majorIncrement;
     const int range = params.gridSize;
 

src/ViewportWidget.cpp

@@ -154,7 +154,7 @@ void ViewportWidget::paintGL()
     m_snapping->paintGL();
 
     if (m_camera->isRotating()) {
-        const float radius = 0.004f * -m_camera->zoom();
+        const float radius = 0.004f * -m_camera->uiCameraDistance();
         const int numSegments = 16;
         QMatrix4x4 invModelView = m_camera->modelViewMatrix().inverted();
         QVector3D rightVec = invModelView.column(0).toVector3D();
@@ -204,7 +204,7 @@ void ViewportWidget::paintGL()
     }
 
     painter.setPen(Qt::white);
-    painter.drawText(width() - 350, height() - 10, QString("Camera Distance: %1").arg(-m_camera->zoom()));
+    painter.drawText(width() - 350, height() - 10, QString("Camera Distance: %1").arg(-m_camera->uiCameraDistance()));
 
     painter.end();
 }
@@ -560,7 +560,7 @@ void ViewportWidget::drawSketch(const SketchFeature* sketch)
     }
 
     if (!unattachedVertices.isEmpty()) {
-        const float radius = 0.004f * -m_camera->zoom();
+        const float radius = 0.004f * -m_camera->uiCameraDistance();
         const int numSegments = 16;
         QMatrix4x4 invModelView = m_camera->modelViewMatrix().inverted();
         QVector3D rightVec = invModelView.column(0).toVector3D();