Fix #9057, offset value misplaced when exporting composer to image

- Add unit test and control images

Author: dakcarto

src/core/qgspallabeling.cpp

@@ -4591,8 +4591,8 @@ void QgsPalLabeling::drawLabelBackground( QgsRenderContext& context,
     p->save();
     p->translate( QPointF( component.center().x(), component.center().y() ) );
     p->rotate( component.rotation() );
-    double xoff = tmpLyr.scaleToPixelContext( tmpLyr.shapeOffset.x(), context, tmpLyr.shapeOffsetUnits, true );
-    double yoff = tmpLyr.scaleToPixelContext( tmpLyr.shapeOffset.y(), context, tmpLyr.shapeOffsetUnits, true );
+    double xoff = tmpLyr.scaleToPixelContext( tmpLyr.shapeOffset.x(), context, tmpLyr.shapeOffsetUnits, false );
+    double yoff = tmpLyr.scaleToPixelContext( tmpLyr.shapeOffset.y(), context, tmpLyr.shapeOffsetUnits, false );
     p->translate( QPointF( xoff, yoff ) );
     p->rotate( component.rotationOffset() );
 

tests/src/python/test_qgspallabeling_tests.py

@@ -58,6 +58,25 @@ def test_text_color(self):
         self.lyr.textColor = Qt.blue
         self.checkTest()
 
+    def test_background_rect(self):
+        self.lyr.shapeDraw = True
+        self.checkTest()
+
+    def test_background_rect_w_offset(self):
+        # Label rectangular background
+        # verify fix for issues
+        #   http://hub.qgis.org/issues/9057
+        #   http://gis.stackexchange.com/questions/86900
+        self.lyr.fontSizeInMapUnits = True
+        font = QFont(self._TestFont)
+        font.setPointSizeF(460)
+        self.lyr.textFont = font
+
+        self.lyr.shapeDraw = True
+        self.lyr.shapeOffsetUnits = QgsPalLayerSettings.MapUnits
+        self.lyr.shapeOffset = QPointF(-2900.0, -450.0 )
+        self.checkTest()
+
     def test_partials_labels_enabled(self):
         # Set Big font size
         font = QFont(self._TestFont)