Expose some useful API from QgsLegendPatchShape

qgis · Oct 11, 2021 · 1f73983 · 1f73983
1 parent ca71c92
commit 1f73983
Show file tree

Hide file tree

Showing 4 changed files with 137 additions and 37 deletions.
diff --git a/python/core/auto_generated/layertree/qgslegendpatchshape.sip.in b/python/core/auto_generated/layertree/qgslegendpatchshape.sip.in
@@ -110,6 +110,39 @@ it is resized to fit a desired legend patch size.
 The default behavior is to respect the :py:func:`~QgsLegendPatchShape.geometry`'s aspect ratio.
 
 .. seealso:: :py:func:`setPreserveAspectRatio`
+%End
+
+    bool scaleToOutputSize() const;
+%Docstring
+Returns ``True`` if the patch shape should by resized to the desired target size
+when rendering.
+
+Resizing to the target size is the default behavior.
+
+.. seealso:: :py:func:`setScaleToOutputSize`
+
+.. versionadded:: 3.22
+%End
+
+    void setScaleToOutputSize( bool scale );
+%Docstring
+Sets whether the patch shape should by resized to the desired target size
+when rendering.
+
+Resizing to the target size is the default behavior.
+
+.. seealso:: :py:func:`scaleToOutputSize`
+
+.. versionadded:: 3.22
+%End
+
+    QgsGeometry scaledGeometry( QSizeF size ) const;
+%Docstring
+Returns the patch shape's geometry, scaled to the given size.
+
+Note that if :py:func:`~QgsLegendPatchShape.scaleToOutputSize` is ``False`` then no scaling will be applied.
+
+.. versionadded:: 3.22
 %End
 
     QList< QList< QPolygonF > > toQPolygonF( Qgis::SymbolType type, QSizeF size ) const;

diff --git a/src/core/layertree/qgslegendpatchshape.cpp b/src/core/layertree/qgslegendpatchshape.cpp
@@ -54,6 +54,16 @@ void QgsLegendPatchShape::setPreserveAspectRatio( bool preserveAspectRatio )
   mPreserveAspectRatio = preserveAspectRatio;
 }
 
+bool QgsLegendPatchShape::scaleToOutputSize() const
+{
+  return mScaleToTargetSize;
+}
+
+void QgsLegendPatchShape::setScaleToOutputSize( bool scale )
+{
+  mScaleToTargetSize = scale;
+}
+
 QPolygonF lineStringToQPolygonF( const QgsLineString *line )
 {
   const double *srcX = line->xData();
@@ -81,52 +91,61 @@ QPolygonF curveToPolygonF( const QgsCurve *curve )
   }
 }
 
-QList<QList<QPolygonF> > QgsLegendPatchShape::toQPolygonF( Qgis::SymbolType type, QSizeF size ) const
+QgsGeometry QgsLegendPatchShape::scaledGeometry( QSizeF size ) const
 {
-  if ( isNull() || type != mSymbolType )
-    return QgsStyle::defaultStyle()->defaultPatchAsQPolygonF( type, size );
+  QgsGeometry geom = mGeometry;
+  if ( mScaleToTargetSize )
+  {
+    // scale and translate to desired size
 
-  // scale and translate to desired size
+    const QRectF bounds = mGeometry.boundingBox().toRectF();
 
-  const QRectF bounds = mGeometry.boundingBox().toRectF();
+    double dx = 0;
+    double dy = 0;
+    if ( mPreserveAspectRatio && bounds.height() > 0 && bounds.width() > 0 )
+    {
+      const double scaling = std::min( size.width() / bounds.width(), size.height() / bounds.height() );
+      const QSizeF scaledSize = bounds.size() * scaling;
+      dx = ( size.width() - scaledSize.width() ) / 2.0;
+      dy = ( size.height() - scaledSize.height() ) / 2.0;
+      size = scaledSize;
+    }
 
-  double dx = 0;
-  double dy = 0;
-  if ( mPreserveAspectRatio && bounds.height() > 0 && bounds.width() > 0 )
-  {
-    const double scaling = std::min( size.width() / bounds.width(), size.height() / bounds.height() );
-    const QSizeF scaledSize = bounds.size() * scaling;
-    dx = ( size.width() - scaledSize.width() ) / 2.0;
-    dy = ( size.height() - scaledSize.height() ) / 2.0;
-    size = scaledSize;
-  }
+    // important -- the transform needs to flip from north-up to painter style "increasing y down" coordinates
+    const QPolygonF targetRectPoly = QPolygonF() << QPointF( dx, dy + size.height() )
+                                     << QPointF( dx + size.width(), dy + size.height() )
+                                     << QPointF( dx + size.width(), dy )
+                                     << QPointF( dx, dy );
+    QTransform t;
 
-  // important -- the transform needs to flip from north-up to painter style "increasing y down" coordinates
-  const QPolygonF targetRectPoly = QPolygonF() << QPointF( dx, dy + size.height() )
-                                   << QPointF( dx + size.width(), dy + size.height() )
-                                   << QPointF( dx + size.width(), dy )
-                                   << QPointF( dx, dy );
-  QTransform t;
+    if ( bounds.width() > 0 && bounds.height() > 0 )
+    {
+      QPolygonF patchRectPoly = QPolygonF( bounds );
+      //workaround QT Bug #21329
+      patchRectPoly.pop_back();
 
-  if ( bounds.width() > 0 && bounds.height() > 0 )
-  {
-    QPolygonF patchRectPoly = QPolygonF( bounds );
-    //workaround QT Bug #21329
-    patchRectPoly.pop_back();
+      QTransform::quadToQuad( patchRectPoly, targetRectPoly, t );
+    }
+    else if ( bounds.width() > 0 )
+    {
+      t = QTransform::fromScale( size.width() / bounds.width(), 1 ).translate( -bounds.left(), size.height() / 2 - bounds.y() );
+    }
+    else if ( bounds.height() > 0 )
+    {
+      t = QTransform::fromScale( 1, size.height() / bounds.height() ).translate( size.width() / 2 - bounds.x(), -bounds.top() );
+    }
 
-    QTransform::quadToQuad( patchRectPoly, targetRectPoly, t );
-  }
-  else if ( bounds.width() > 0 )
-  {
-    t = QTransform::fromScale( size.width() / bounds.width(), 1 ).translate( -bounds.left(), size.height() / 2 - bounds.y() );
-  }
-  else if ( bounds.height() > 0 )
-  {
-    t = QTransform::fromScale( 1, size.height() / bounds.height() ).translate( size.width() / 2 - bounds.x(), -bounds.top() );
+    geom.transform( t );
   }
+  return geom;
+}
 
-  QgsGeometry geom = mGeometry;
-  geom.transform( t );
+QList<QList<QPolygonF> > QgsLegendPatchShape::toQPolygonF( Qgis::SymbolType type, QSizeF size ) const
+{
+  if ( isNull() || type != mSymbolType )
+    return QgsStyle::defaultStyle()->defaultPatchAsQPolygonF( type, size );
+
+  const QgsGeometry geom = scaledGeometry( size );
 
   switch ( mSymbolType )
   {

diff --git a/src/core/layertree/qgslegendpatchshape.h b/src/core/layertree/qgslegendpatchshape.h
@@ -122,6 +122,37 @@ class CORE_EXPORT QgsLegendPatchShape
      */
     void setPreserveAspectRatio( bool preserve );
 
+    /**
+     * Returns TRUE if the patch shape should by resized to the desired target size
+     * when rendering.
+     *
+     * Resizing to the target size is the default behavior.
+     *
+     * \see setScaleToOutputSize()
+     * \since QGIS 3.22
+     */
+    bool scaleToOutputSize() const;
+
+    /**
+     * Sets whether the patch shape should by resized to the desired target size
+     * when rendering.
+     *
+     * Resizing to the target size is the default behavior.
+     *
+     * \see scaleToOutputSize()
+     * \since QGIS 3.22
+     */
+    void setScaleToOutputSize( bool scale );
+
+    /**
+     * Returns the patch shape's geometry, scaled to the given size.
+     *
+     * Note that if scaleToOutputSize() is FALSE then no scaling will be applied.
+     *
+     * \since QGIS 3.22
+     */
+    QgsGeometry scaledGeometry( QSizeF size ) const;
+
     /**
      * Converts the patch shape to a set of QPolygonF objects representing
      * how the patch should be drawn for a symbol of the given \a type at the specified \a size (as
@@ -145,6 +176,7 @@ class CORE_EXPORT QgsLegendPatchShape
     Qgis::SymbolType mSymbolType = Qgis::SymbolType::Fill;
     QgsGeometry mGeometry;
     bool mPreserveAspectRatio = true;
+    bool mScaleToTargetSize = true;
 
 };
 

diff --git a/tests/src/python/test_qgslegendpatchshape.py b/tests/src/python/test_qgslegendpatchshape.py
@@ -71,6 +71,10 @@ def testBasic(self):
         shape.setPreserveAspectRatio(True)
         self.assertTrue(shape.preserveAspectRatio())
 
+        self.assertTrue(shape.scaleToOutputSize())
+        shape.setScaleToOutputSize(False)
+        self.assertFalse(shape.scaleToOutputSize())
+
     @staticmethod
     def polys_to_list(polys):
         return [[[[round(p.x(), 3), round(p.y(), 3)] for p in ring] for ring in poly] for poly in polys]
@@ -188,6 +192,18 @@ def testFills(self):
         self.assertEqual(self.polys_to_list(shape.toQPolygonF(QgsSymbol.Fill, QSizeF(1, 1))), [[[[0.4, 0.667], [0.0, 1.0], [0.2, 0.778], [0.4, 0.667]], [[0.35, 0.722], [0.34, 0.733], [0.35, 0.733], [0.35, 0.722]]], [[[0.9, 0.0], [1.0, 0.0], [1.0, 0.111], [0.9, 0.0]]]])
         self.assertEqual(self.polys_to_list(shape.toQPolygonF(QgsSymbol.Fill, QSizeF(10, 2))), [[[[4.0, 1.333], [0.0, 2.0], [2.0, 1.556], [4.0, 1.333]], [[3.5, 1.444], [3.4, 1.467], [3.5, 1.467], [3.5, 1.444]]], [[[9.0, 0.0], [10.0, 0.0], [10.0, 0.222], [9.0, 0.0]]]])
 
+    def testScaledGeometry(self):
+        """
+        Test scaling geometry
+        """
+        shape = QgsLegendPatchShape(QgsSymbol.Line, QgsGeometry.fromWkt('LineString(5 5, 1 2)'))
+
+        self.assertEqual(shape.scaledGeometry(QSizeF(20, 30)).asWkt(1), 'LineString (20 7.5, 0 22.5)')
+        self.assertEqual(shape.scaledGeometry(QSizeF(200, 300)).asWkt(1), 'LineString (200 75, 0 225)')
+        shape.setScaleToOutputSize(False)
+        self.assertEqual(shape.scaledGeometry(QSizeF(20, 30)).asWkt(1), 'LineString (5 5, 1 2)')
+        self.assertEqual(shape.scaledGeometry(QSizeF(200, 300)).asWkt(1), 'LineString (5 5, 1 2)')
+
     def testRenderMarker(self):
         shape = QgsLegendPatchShape(QgsSymbol.Marker, QgsGeometry.fromWkt('MultiPoint((5 5), (3 4), (1 2))'), False)
         rendered_image = self.renderPatch(shape)