Don't draw items which are a clip source for a map

nyalldawson · nyalldawson · commit c5b3443cb30f · 2020-07-28T15:12:04.000+10:00
diff --git a/python/core/auto_generated/layout/qgslayoututils.sip.in b/python/core/auto_generated/layout/qgslayoututils.sip.in
@@ -244,6 +244,13 @@ This method will return an optimal round number which falls within the given ran
 the largest "pretty" number possible.
 
 .. versionadded:: 3.10
+%End
+
+    static bool itemIsAClippingSource( const QgsLayoutItem *item );
+%Docstring
+Returns ``True`` if an ``item`` is a clipping item for another layout item.
+
+.. versionadded:: 3.16
 %End
 
 };
diff --git a/src/core/layout/qgslayoutitem.cpp b/src/core/layout/qgslayoutitem.cpp
@@ -589,6 +589,9 @@ bool QgsLayoutItem::shouldBlockUndoCommands() const
 
 bool QgsLayoutItem::shouldDrawItem() const
 {
+  if ( mLayout && QgsLayoutUtils::itemIsAClippingSource( this ) )
+    return false;
+
   if ( !mLayout || mLayout->renderContext().isPreviewRender() )
   {
     //preview mode so OK to draw item
diff --git a/src/core/layout/qgslayoututils.cpp b/src/core/layout/qgslayoututils.cpp
@@ -461,6 +461,22 @@ double QgsLayoutUtils::calculatePrettySize( const double minimumSize, const doub
   }
 }
 
+bool QgsLayoutUtils::itemIsAClippingSource( const QgsLayoutItem *item )
+{
+  if ( !( item->itemFlags() & QgsLayoutItem::FlagProvidesClipPath ) )
+    return false; // not a clipping provider, so shortcut out
+
+  // current only maps can be clipped
+  QList< QgsLayoutItemMap * > maps;
+  item->layout()->layoutItems( maps );
+  for ( QgsLayoutItemMap *map : qgis::as_const( maps ) )
+  {
+    if ( map->itemClippingSettings()->isActive() && map->itemClippingSettings()->sourceItem() == item )
+      return true;
+  }
+  return false;
+}
+
 double QgsLayoutUtils::pointsToMM( const double pointSize )
 {
   //conversion to mm based on 1 point = 1/72 inch
diff --git a/src/core/layout/qgslayoututils.h b/src/core/layout/qgslayoututils.h
@@ -232,6 +232,13 @@ class CORE_EXPORT QgsLayoutUtils
      */
     static double calculatePrettySize( double minimumSize, double maximumSize );
 
+    /**
+     * Returns TRUE if an \a item is a clipping item for another layout item.
+     *
+     * \since QGIS 3.16
+     */
+    static bool itemIsAClippingSource( const QgsLayoutItem *item );
+
   private:
 
     //! Scale factor for upscaling fontsize and downscaling painter
diff --git a/tests/src/python/test_qgslayoutmap.py b/tests/src/python/test_qgslayoutmap.py
@@ -662,6 +662,66 @@ def testClippingOverview(self):
         self.report += checker.report()
         self.assertTrue(result, message)
 
+    def testClippingHideClipSource(self):
+        """
+        When an item is set to be the clip source, it shouldn't render anything itself
+        """
+        format = QgsTextFormat()
+        format.setFont(QgsFontUtils.getStandardTestFont("Bold"))
+        format.setSize(30)
+        format.setNamedStyle("Bold")
+        format.setColor(QColor(0, 0, 0))
+        settings = QgsPalLayerSettings()
+        settings.setFormat(format)
+        settings.fieldName = "'XXXX'"
+        settings.isExpression = True
+        settings.placement = QgsPalLayerSettings.OverPoint
+
+        vl = QgsVectorLayer("Polygon?crs=epsg:4326&field=id:integer", "vl", "memory")
+
+        props = {"color": "127,255,127", 'outline_style': 'solid', 'outline_width': '1', 'outline_color': '0,0,255'}
+        fillSymbol = QgsFillSymbol.createSimple(props)
+        renderer = QgsSingleSymbolRenderer(fillSymbol)
+        vl.setRenderer(renderer)
+
+        f = QgsFeature(vl.fields(), 1)
+        for x in range(0, 15, 3):
+            for y in range(0, 15, 3):
+                f.setGeometry(QgsGeometry(QgsPoint(x, y)).buffer(1, 3))
+                vl.dataProvider().addFeature(f)
+
+        vl.setLabeling(QgsVectorLayerSimpleLabeling(settings))
+        vl.setLabelsEnabled(True)
+
+        p = QgsProject()
+
+        p.addMapLayer(vl)
+        layout = QgsLayout(p)
+        layout.initializeDefaults()
+        p.setCrs(QgsCoordinateReferenceSystem('EPSG:4326'))
+        map = QgsLayoutItemMap(layout)
+        map.attemptSetSceneRect(QRectF(10, 10, 180, 180))
+        map.setFrameEnabled(True)
+        map.zoomToExtent(vl.extent())
+        map.setLayers([vl])
+        layout.addLayoutItem(map)
+
+        shape = QgsLayoutItemShape(layout)
+        layout.addLayoutItem(shape)
+        shape.setShapeType(QgsLayoutItemShape.Ellipse)
+        shape.attemptSetSceneRect(QRectF(10, 10, 180, 180))
+
+        map.itemClippingSettings().setEnabled(True)
+        map.itemClippingSettings().setSourceItem(shape)
+        map.itemClippingSettings().setForceLabelsInsideClipPath(False)
+        map.itemClippingSettings().setFeatureClippingType(QgsMapClippingRegion.FeatureClippingType.ClipToIntersection)
+
+        checker = QgsLayoutChecker('composermap_itemclip_nodrawsource', layout)
+        checker.setControlPathPrefix("composer_map")
+        result, message = checker.testLayout()
+        self.report += checker.report()
+        self.assertTrue(result, message)
+
 
 if __name__ == '__main__':
     unittest.main()

Original file line number	Diff line number	Diff line change
`@@ -589,6 +589,9 @@ bool QgsLayoutItem::shouldBlockUndoCommands() const`
`589`	`589`
`590`	`590`	`bool QgsLayoutItem::shouldDrawItem() const`
`591`	`591`	`{`
	`592`	`+ if ( mLayout && QgsLayoutUtils::itemIsAClippingSource( this ) )`
	`593`	`+ return false;`
	`594`	`+`
`592`	`595`	`if ( !mLayout \|\| mLayout->renderContext().isPreviewRender() )`
`593`	`596`	`{`
`594`	`597`	`//preview mode so OK to draw item`