add option to cropTransparent to allow centering

use that in qgslayertreemodellegendnode
qgis · May 12, 2015 · b8bc181 · b8bc181
1 parent d13ace5
commit b8bc181
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Showing 4 changed files with 31 additions and 13 deletions.
diff --git a/python/core/effects/qgsimageoperation.sip b/python/core/effects/qgsimageoperation.sip
@@ -136,8 +136,9 @@ class QgsImageOperation
      * @param minSize minimum size for cropped image, if desired. If the
      * cropped image is smaller than the minimum size, it will be centered
      * in the returned image.
+     * @param center croped image will be centered on the center of the original image
      * @note added in QGIS 2.9
      */
-    static QImage cropTransparent( const QImage & image, const QSize& minSize = QSize() );
+    static QImage cropTransparent( const QImage & image, const QSize& minSize = QSize(), bool center = false );
 
 };
diff --git a/src/core/effects/qgsimageoperation.cpp b/src/core/effects/qgsimageoperation.cpp
@@ -793,7 +793,7 @@ void QgsImageOperation::flipImage( QImage &image, QgsImageOperation::FlipType ty
   runLineOperation( image, flipOperation );
 }
 
-QImage QgsImageOperation::cropTransparent( const QImage &image, const QSize &minSize )
+QImage QgsImageOperation::cropTransparent( const QImage &image, const QSize &minSize, bool center )
 {
   int width = image.width();
   int height = image.height();
@@ -828,6 +828,16 @@ QImage QgsImageOperation::cropTransparent( const QImage &image, const QSize &min
       ymax = ymin + minSize.height();
     }
   }
+  if ( center )
+  {
+    // recompute min and max to center image
+    const int dx = qMax( qAbs( xmax - width / 2 ), qAbs( xmin - width / 2 ) );
+    const int dy = qMax( qAbs( ymax - height / 2 ), qAbs( ymin - height / 2 ) );
+    xmin = qMax( 0, width / 2 - dx );
+    xmax = qMin( width, width / 2 + dx );
+    ymin = qMax( 0, height / 2 - dy );
+    ymax = qMin( height, height / 2 + dy );
+  }
   return image.copy( xmin, ymin, xmax - xmin, ymax - ymin );
 }
 

diff --git a/src/core/effects/qgsimageoperation.h b/src/core/effects/qgsimageoperation.h
@@ -167,9 +167,10 @@ class CORE_EXPORT QgsImageOperation
      * @param minSize minimum size for cropped image, if desired. If the
      * cropped image is smaller than the minimum size, it will be centered
      * in the returned image.
+     * @param center croped image will be centered on the center of the original image
      * @note added in QGIS 2.9
      */
-    static QImage cropTransparent( const QImage & image, const QSize& minSize = QSize() );
+    static QImage cropTransparent( const QImage & image, const QSize& minSize = QSize(), bool center = false );
 
   private:
 

diff --git a/src/core/layertree/qgslayertreemodellegendnode.cpp b/src/core/layertree/qgslayertreemodellegendnode.cpp
@@ -163,21 +163,27 @@ QSize QgsSymbolV2LegendNode::minimumIconSize() const
   if ( mItem.symbol() && mItem.symbol()->type() == QgsSymbolV2::Marker )
   {
     QScopedPointer<QgsRenderContext> context( createTemporaryRenderContext() );
-    QPixmap pix = QPixmap::fromImage( QgsImageOperation::cropTransparent(
-                                        QgsSymbolLayerV2Utils::symbolPreviewPixmap( mItem.symbol(),
-                                            QSize( 512, 512 ),
-                                            context.data()
-                                                                                  ).toImage(), mIconSize ) );
+    QPixmap pix = QPixmap::fromImage(
+                    QgsImageOperation::cropTransparent(
+                      QgsSymbolLayerV2Utils::symbolPreviewPixmap(
+                        mItem.symbol(),
+                        QSize( 512, 512 ),
+                        context.data() ).toImage(),
+                      mIconSize,
+                      true ) );
     minSz = pix.size();
   }
   else if ( mItem.symbol() && mItem.symbol()->type() == QgsSymbolV2::Line )
   {
     QScopedPointer<QgsRenderContext> context( createTemporaryRenderContext() );
-    QPixmap pix = QPixmap::fromImage( QgsImageOperation::cropTransparent(
-                                        QgsSymbolLayerV2Utils::symbolPreviewPixmap( mItem.symbol(),
-                                            QSize( mIconSize.width(), 512 ),
-                                            context.data()
-                                                                                  ).toImage(), mIconSize ) );
+    QPixmap pix = QPixmap::fromImage(
+                    QgsImageOperation::cropTransparent(
+                      QgsSymbolLayerV2Utils::symbolPreviewPixmap(
+                        mItem.symbol(),
+                        QSize( mIconSize.width(), 512 ),
+                        context.data() ).toImage(),
+                      mIconSize,
+                      true ) );
     minSz = pix.size();
   }
   else