QgsLayoutItemShape can provide clip paths

qgis · Jul 28, 2020 · 77badc0 · 77badc0
1 parent aa0b36b
commit 77badc0
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Showing 4 changed files with 86 additions and 9 deletions.
diff --git a/python/core/auto_generated/layout/qgslayoutitemshape.sip.in b/python/core/auto_generated/layout/qgslayoutitemshape.sip.in
@@ -49,6 +49,8 @@ The caller takes responsibility for deleting the returned object.
 
     virtual QString displayName() const;
 
+    virtual QgsLayoutItem::Flags itemFlags() const;
+
 
     QgsLayoutItemShape::Shape shapeType() const;
 %Docstring
@@ -93,6 +95,9 @@ Returns the corner radius for rounded rectangle corners.
 .. seealso:: :py:func:`setCornerRadius`
 %End
 
+    virtual QgsGeometry clipPath() const;
+
+
     virtual QRectF boundingRect() const;
 
 

diff --git a/src/core/layout/qgslayoutitemshape.cpp b/src/core/layout/qgslayoutitemshape.cpp
@@ -43,6 +43,7 @@ QgsLayoutItemShape::QgsLayoutItemShape( QgsLayout *layout )
   {
     updateBoundingRect();
     update();
+    emit clipPathChanged();
   } );
 }
 
@@ -91,6 +92,13 @@ QString QgsLayoutItemShape::displayName() const
   return tr( "<Shape>" );
 }
 
+QgsLayoutItem::Flags QgsLayoutItemShape::itemFlags() const
+{
+  QgsLayoutItem::Flags flags = QgsLayoutItem::itemFlags();
+  flags |= QgsLayoutItem::FlagProvidesClipPath;
+  return flags;
+}
+
 void QgsLayoutItemShape::setShapeType( QgsLayoutItemShape::Shape type )
 {
   if ( type == mShape )
@@ -105,6 +113,8 @@ void QgsLayoutItemShape::setShapeType( QgsLayoutItemShape::Shape type )
     //notify the model that the display name has changed
     mLayout->itemsModel()->updateItemDisplayName( this );
   }
+
+  emit clipPathChanged();
 }
 
 void QgsLayoutItemShape::refreshSymbol()
@@ -141,6 +151,21 @@ void QgsLayoutItemShape::setSymbol( QgsFillSymbol *symbol )
   refreshSymbol();
 }
 
+void QgsLayoutItemShape::setCornerRadius( QgsLayoutMeasurement radius )
+{
+  mCornerRadius = radius;
+  emit clipPathChanged();
+}
+
+QgsGeometry QgsLayoutItemShape::clipPath() const
+{
+  QPolygonF shapePolygon = mapToScene( calculatePolygon( 1.0 ) );
+  // ensure polygon is closed
+  if ( shapePolygon.at( 0 ) != shapePolygon.constLast() )
+    shapePolygon << shapePolygon.at( 0 );
+  return QgsGeometry::fromQPolygonF( shapePolygon );
+}
+
 QRectF QgsLayoutItemShape::boundingRect() const
 {
   return mCurrentRectangle;
@@ -169,8 +194,17 @@ void QgsLayoutItemShape::draw( QgsLayoutItemRenderContext &context )
   painter->setPen( Qt::NoPen );
   painter->setBrush( Qt::NoBrush );
 
-  double scale = context.renderContext().convertToPainterUnits( 1, QgsUnitTypes::RenderMillimeters );
+  const double scale = context.renderContext().convertToPainterUnits( 1, QgsUnitTypes::RenderMillimeters );
+
+  QVector<QPolygonF> rings; //empty list
+
+  symbol()->startRender( context.renderContext() );
+  symbol()->renderPolygon( calculatePolygon( scale ), &rings, nullptr, context.renderContext() );
+  symbol()->stopRender( context.renderContext() );
+}
 
+QPolygonF QgsLayoutItemShape::calculatePolygon( double scale ) const
+{
   QPolygonF shapePolygon;
 
   //shapes with curves must be enlarged before conversion to QPolygonF, or
@@ -216,12 +250,7 @@ void QgsLayoutItemShape::draw( QgsLayoutItemRenderContext &context )
       break;
     }
   }
-
-  QVector<QPolygonF> rings; //empty list
-
-  symbol()->startRender( context.renderContext() );
-  symbol()->renderPolygon( shapePolygon, &rings, nullptr, context.renderContext() );
-  symbol()->stopRender( context.renderContext() );
+  return shapePolygon;
 }
 
 bool QgsLayoutItemShape::writePropertiesToElement( QDomElement &element, QDomDocument &document, const QgsReadWriteContext &context ) const

diff --git a/src/core/layout/qgslayoutitemshape.h b/src/core/layout/qgslayoutitemshape.h
@@ -62,6 +62,7 @@ class CORE_EXPORT QgsLayoutItemShape : public QgsLayoutItem
 
     //Overridden to return shape type
     QString displayName() const override;
+    QgsLayoutItem::Flags itemFlags() const override;
 
     /**
      * Returns the type of shape (e.g. rectangle, ellipse, etc).
@@ -92,14 +93,16 @@ class CORE_EXPORT QgsLayoutItemShape : public QgsLayoutItem
      * Sets the corner \a radius for rounded rectangle corners.
      * \see cornerRadius()
      */
-    void setCornerRadius( QgsLayoutMeasurement radius ) { mCornerRadius = radius; }
+    void setCornerRadius( QgsLayoutMeasurement radius );
 
     /**
      * Returns the corner radius for rounded rectangle corners.
      * \see setCornerRadius()
      */
     QgsLayoutMeasurement cornerRadius() const { return mCornerRadius; }
 
+    QgsGeometry clipPath() const override;
+
     // Depending on the symbol style, the bounding rectangle can be larger than the shape
     QRectF boundingRect() const override;
 
@@ -138,6 +141,8 @@ class CORE_EXPORT QgsLayoutItemShape : public QgsLayoutItem
     QRectF mCurrentRectangle;
 
     QgsLayoutMeasurement mCornerRadius;
+
+    QPolygonF calculatePolygon( double scale ) const;
 };
 
 

diff --git a/tests/src/python/test_qgslayoutshape.py b/tests/src/python/test_qgslayoutshape.py
@@ -13,7 +13,16 @@
 import qgis  # NOQA
 
 from qgis.testing import start_app, unittest
-from qgis.core import QgsLayoutItemShape
+from qgis.core import (
+    QgsLayoutItemShape,
+    QgsProject,
+    QgsLayout,
+    QgsLayoutItem,
+    QgsLayoutMeasurement,
+    QgsUnitTypes
+)
+from qgis.PyQt.QtCore import QRectF
+from qgis.PyQt.QtTest import QSignalSpy
 
 from test_qgslayoutitem import LayoutItemTestCase
 
@@ -26,6 +35,35 @@ class TestQgsLayoutShape(unittest.TestCase, LayoutItemTestCase):
     def setUpClass(cls):
         cls.item_class = QgsLayoutItemShape
 
+    def testClipPath(self):
+        pr = QgsProject()
+        l = QgsLayout(pr)
+        shape = QgsLayoutItemShape(l)
+
+        shape.setShapeType(QgsLayoutItemShape.Rectangle)
+        shape.attemptSetSceneRect(QRectF(30, 10, 100, 200))
+
+        # must be a closed polygon, in scene coordinates!
+        self.assertEqual(shape.clipPath().asWkt(), 'Polygon ((30 10, 130 10, 130 210, 30 210, 30 10))')
+        self.assertTrue(int(shape.itemFlags() & QgsLayoutItem.FlagProvidesClipPath))
+
+        spy = QSignalSpy(shape.clipPathChanged)
+        shape.setCornerRadius(QgsLayoutMeasurement(10, QgsUnitTypes.LayoutMillimeters))
+        self.assertTrue(shape.clipPath().asWkt(0).startswith('Polygon ((30 20, 30 20, 30 19, 30 19, 30 19, 30 19'))
+        self.assertEqual(len(spy), 1)
+
+        shape.setShapeType(QgsLayoutItemShape.Ellipse)
+        self.assertEqual(len(spy), 2)
+        self.assertTrue(shape.clipPath().asWkt(0).startswith('Polygon ((130 110, 130 111, 130 113, 130 114'))
+
+        shape.setShapeType(QgsLayoutItemShape.Triangle)
+        self.assertEqual(len(spy), 3)
+        self.assertEqual(shape.clipPath().asWkt(), 'Polygon ((30 210, 130 210, 80 10, 30 210))')
+
+        shape.attemptSetSceneRect(QRectF(50, 20, 80, 120))
+        self.assertEqual(len(spy), 4)
+        self.assertEqual(shape.clipPath().asWkt(), 'Polygon ((50 140, 130 140, 90 20, 50 140))')
+
 
 if __name__ == '__main__':
     unittest.main()