Sketcher: [skip ci] refactor SoDatumLabel

src/Mod/Sketcher/Gui/SoDatumLabel.cpp

@@ -417,15 +417,8 @@ void SoDatumLabel::notify(SoNotList * l)
     inherited::notify(l);
 }
 
-void SoDatumLabel::GLRender(SoGLRenderAction * action)
+float SoDatumLabel::getScaleFactor(SoState* state) const
 {
-    SoState *state = action->getState();
-
-    if (!shouldGLRender(action))
-        return;
-    if (action->handleTransparency(true))
-      return;
-
     /**Remark from Stefan Tröger:
     * The scale calculation is based on knowledge of SbViewVolume::getWorldToScreenScale
     * implementation internals. The factor returned from this function is calculated from the view frustums
@@ -448,6 +441,20 @@ void SoDatumLabel::GLRender(SoGLRenderAction * action)
     SbVec2s vp_size = vp.getViewportSizePixels();
     scale /= float(vp_size[0]);
 
+    return scale;
+}
+
+void SoDatumLabel::GLRender(SoGLRenderAction * action)
+{
+    SoState *state = action->getState();
+
+    if (!shouldGLRender(action))
+        return;
+    if (action->handleTransparency(true))
+      return;
+
+    float scale = getScaleFactor(state);
+
     const SbString* s = string.getValues(0);
     bool hasText = (s->getLength() > 0) ? true : false;
 
@@ -903,6 +910,7 @@ void SoDatumLabel::GLRender(SoGLRenderAction * action)
         const unsigned char * dataptr = this->image.getValue(imgsize, nc);
 
         //Get the camera z-direction
+        const SbViewVolume & vv = SoViewVolumeElement::get(state);
         SbVec3f z = vv.zVector();
 
         bool flip = norm.getValue().dot(z) > FLT_EPSILON;

src/Mod/Sketcher/Gui/SoDatumLabel.h

@@ -47,16 +47,16 @@ class SketcherGuiExport SoDatumLabel : public SoShape {
     SO_NODE_HEADER(SoDatumLabel);
 
 public:
-  enum Type
-  {
-  ANGLE,
-  DISTANCE,
-  DISTANCEX,
-  DISTANCEY,
-  RADIUS,
-  DIAMETER,
-  SYMMETRIC
-  };
+    enum Type
+    {
+        ANGLE,
+        DISTANCE,
+        DISTANCEX,
+        DISTANCEY,
+        RADIUS,
+        DIAMETER,
+        SYMMETRIC
+    };
 
     static void initClass();
     SoDatumLabel();
@@ -76,12 +76,15 @@ public:
     bool       useAntialiasing;
 
 protected:
-    ~SoDatumLabel() override {};
+    ~SoDatumLabel() override {}
     void GLRender(SoGLRenderAction *action) override;
     void computeBBox(SoAction *, SbBox3f &box, SbVec3f &center) override;
     void generatePrimitives(SoAction * action) override;
     void notify(SoNotList * l) override;
 
+private:
+    float getScaleFactor(SoState*) const;
+
 private:
     void drawImage();
     SbBox3f bbox;