Sorting of raster color ramp items: better and faster.

... why to use insert sort if we have quicksort for free ...? :)

(was taking minutes for one raster layer)


git-svn-id: http://svn.osgeo.org/qgis/trunk@10604 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: wonder

src/app/qgsrasterlayerproperties.cpp

@@ -1371,8 +1371,6 @@ void QgsRasterLayerProperties::apply()
       //iterate through mColormapTreeWidget and set colormap info of layer
       QList<QgsColorRampShader::ColorRampItem> myColorRampItems;
 
-      bool inserted = false;
-      int myCurrentIndex = 0;
       int myTopLevelItemCount = mColormapTreeWidget->topLevelItemCount();
       QTreeWidgetItem* myCurrentItem;
       for ( int i = 0; i < myTopLevelItemCount; ++i )
@@ -1386,35 +1384,13 @@ void QgsRasterLayerProperties::apply()
         myNewColorRampItem.value = myCurrentItem->text( 0 ).toDouble();
         myNewColorRampItem.color = myCurrentItem->background( 1 ).color();
         myNewColorRampItem.label = myCurrentItem->text( 2 );
-
-        //Simple insertion sort - speed is not a huge factor here
-        inserted = false;
-        myCurrentIndex = 0;
-        while ( !inserted )
-        {
-          if ( 0 == myColorRampItems.size() || myCurrentIndex == myColorRampItems.size() )
-          {
-            myColorRampItems.push_back( myNewColorRampItem );
-            inserted = true;
-          }
-          else if ( myColorRampItems[myCurrentIndex].value > myNewColorRampItem.value )
-          {
-            myColorRampItems.insert( myCurrentIndex, myNewColorRampItem );
-            inserted = true;
-          }
-          else if ( myColorRampItems[myCurrentIndex].value <= myNewColorRampItem.value  && myCurrentIndex == myColorRampItems.size() - 1 )
-          {
-            myColorRampItems.push_back( myNewColorRampItem );
-            inserted = true;
-          }
-          else if ( myColorRampItems[myCurrentIndex].value <= myNewColorRampItem.value && myColorRampItems[myCurrentIndex+1].value > myNewColorRampItem.value )
-          {
-            myColorRampItems.insert( myCurrentIndex + 1, myNewColorRampItem );
-            inserted = true;
-          }
-          myCurrentIndex++;
-        }
+        
+        myColorRampItems.append( myNewColorRampItem );
       }
+      
+      // sort the shader items
+      qSort(myColorRampItems);
+      
       myRasterShaderFunction->setColorRampItemList( myColorRampItems );
       //Reload table in GUI because it may have been sorted or contained invalid values
       populateColorMapTable( myColorRampItems );

src/core/raster/qgscolorrampshader.h

@@ -44,6 +44,9 @@ class CORE_EXPORT QgsColorRampShader : public QgsRasterShaderFunction
       QString label;
       double value;
       QColor color;
+      
+      // compare operator for sorting
+      bool operator<(const ColorRampItem& other) const { return value < other.value; }
     };
 
     enum ColorRamp_TYPE