Use QImage method for bilinear resampling

mhugent · mhugent · commit 28313b6aeb8d · 2012-01-07T13:12:44.000+01:00
diff --git a/src/core/raster/qgsbilinearrasterresampler.cpp b/src/core/raster/qgsbilinearrasterresampler.cpp
@@ -29,99 +29,5 @@ QgsBilinearRasterResampler::~QgsBilinearRasterResampler()
 
 void QgsBilinearRasterResampler::resample( const QImage& srcImage, QImage& dstImage )
 {
-  double nSrcPerDstX = ( double ) srcImage.width() / ( double ) dstImage.width();
-  double nSrcPerDstY = ( double ) srcImage.height() / ( double ) dstImage.height();
-
-  double currentSrcRow = nSrcPerDstY / 2.0 - 0.5;
-  double currentSrcCol;
-  int currentSrcRowInt, currentSrcColInt;
-  double u, v;
-
-  QRgb px1, px2, px3, px4;
-
-  for ( int i = 0; i < dstImage.height(); ++i )
-  {
-    currentSrcCol = nSrcPerDstX / 2.0 - 0.5;
-    currentSrcRowInt = floor( currentSrcRow );
-    v = currentSrcRow - currentSrcRowInt;
-
-    for ( int j = 0; j < dstImage.width(); ++j )
-    {
-      currentSrcColInt = floor( currentSrcCol );
-      u = currentSrcCol - currentSrcColInt;
-
-      //handle eight edge-cases
-      if ( currentSrcRowInt < 0 || currentSrcRowInt >= ( srcImage.height() - 1 ) || currentSrcColInt < 0 || currentSrcColInt >= ( srcImage.width() - 1 ) )
-      {
-        //pixels at the border of the source image needs to be handled in a special way
-        if ( currentSrcRowInt < 0 && currentSrcColInt < 0 )
-        {
-          dstImage.setPixel( j, i, srcImage.pixel( 0, 0 ) );
-        }
-        else if ( currentSrcRowInt < 0 && currentSrcColInt >= ( srcImage.width() - 1 ) )
-        {
-          dstImage.setPixel( j, i, srcImage.pixel( srcImage.width() - 1, 0 ) );
-        }
-        else if ( currentSrcRowInt >= ( srcImage.height() - 1 ) && currentSrcColInt >= ( srcImage.width() - 1 ) )
-        {
-          dstImage.setPixel( j, i, srcImage.pixel( srcImage.width() - 1, srcImage.height() - 1 ) );
-        }
-        else if ( currentSrcRowInt >= ( srcImage.height() - 1 ) && currentSrcColInt < 0 )
-        {
-          dstImage.setPixel( j, i, srcImage.pixel( 0, srcImage.height() - 1 ) );
-        }
-        else if ( currentSrcRowInt < 0 )
-        {
-          px1 = srcImage.pixel( currentSrcColInt, 0 );
-          px2 = srcImage.pixel( currentSrcColInt + 1, 0 );
-          dstImage.setPixel( j, i, resampleColorValue( u, px1, px2 ) );
-        }
-        else if ( currentSrcRowInt >= ( srcImage.height() - 1 ) )
-        {
-          px1 = srcImage.pixel( currentSrcColInt, srcImage.height() - 1 );
-          px2 = srcImage.pixel( currentSrcColInt + 1, srcImage.height() - 1 );
-          dstImage.setPixel( j, i, resampleColorValue( u, px1, px2 ) );
-        }
-        else if ( currentSrcColInt < 0 )
-        {
-          px1 = srcImage.pixel( 0, currentSrcRowInt );
-          px2 = srcImage.pixel( 0, currentSrcRowInt + 1 );
-          dstImage.setPixel( j, i, resampleColorValue( v, px1, px2 ) );
-        }
-        else if ( currentSrcColInt >= ( srcImage.width() - 1 ) )
-        {
-          px1 = srcImage.pixel( srcImage.width() - 1, currentSrcRowInt );
-          px2 = srcImage.pixel( srcImage.width() - 1, currentSrcRowInt + 1 );
-          dstImage.setPixel( j, i, resampleColorValue( v, px1, px2 ) );
-        }
-        currentSrcCol += nSrcPerDstX;
-        continue;
-      }
-
-      px1 = srcImage.pixel( currentSrcColInt, currentSrcRowInt );
-      px2 = srcImage.pixel( currentSrcColInt + 1, currentSrcRowInt );
-      px3 = srcImage.pixel( currentSrcColInt + 1, currentSrcRowInt + 1 );
-      px4 = srcImage.pixel( currentSrcColInt, currentSrcRowInt + 1 );
-      dstImage.setPixel( j, i, resampleColorValue( u, v, px1, px2, px3, px4 ) );
-      currentSrcCol += nSrcPerDstX;
-    }
-    currentSrcRow += nSrcPerDstY;
-  }
-}
-
-QRgb QgsBilinearRasterResampler::resampleColorValue( double u, double v, QRgb col1, QRgb col2, QRgb col3, QRgb col4 ) const
-{
-  int red = bilinearInterpolation( u, v, qRed( col1 ), qRed( col2 ), qRed( col3 ), qRed( col4 ) );
-  int green = bilinearInterpolation( u, v, qGreen( col1 ), qGreen( col2 ), qGreen( col3 ), qGreen( col4 ) );
-  int blue = bilinearInterpolation( u, v, qBlue( col1 ), qBlue( col2 ), qBlue( col3 ), qBlue( col4 ) );
-  int alpha = bilinearInterpolation( u, v, qAlpha( col1 ), qAlpha( col2 ), qAlpha( col3 ), qAlpha( col4 ) );
-  return qRgba( red, green, blue, alpha );
-}
-
-QRgb QgsBilinearRasterResampler::resampleColorValue( double u, QRgb col1, QRgb col2 ) const
-{
-  return qRgba( qRed( col1 ) * ( 1 - u ) + qRed( col2 ) * u,
-                qGreen( col1 ) * ( 1 - u ) + qGreen( col2 ) * u,
-                qBlue( col1 ) * ( 1 - u ) + qBlue( col2 ) * u,
-                qAlpha( col1 ) * ( 1 - u ) + qAlpha( col2 ) * u );
+  dstImage = srcImage.scaled( dstImage.width(), dstImage.height(), Qt::IgnoreAspectRatio, Qt::SmoothTransformation );
 }
diff --git a/src/core/raster/qgsbilinearrasterresampler.h b/src/core/raster/qgsbilinearrasterresampler.h
@@ -29,16 +29,6 @@ class QgsBilinearRasterResampler: public QgsRasterResampler
 
     void resample( const QImage& srcImage, QImage& dstImage );
     QString type() const { return "bilinear"; }
-
-  private:
-    QRgb resampleColorValue( double u, double v, QRgb col1, QRgb col2, QRgb col3, QRgb col4 ) const;
-    QRgb resampleColorValue( double u, QRgb col1, QRgb col2 ) const;
-    inline double bilinearInterpolation( double u, double v, int val1, int val2, int val3, int val4 ) const;
 };
 
-double QgsBilinearRasterResampler::bilinearInterpolation( double u, double v, int val1, int val2, int val3, int val4 ) const
-{
-  return ( val1 * ( 1 - u ) * ( 1 - v ) + val2 * ( 1 - v ) * u + val4 * ( 1 - u ) * v + val3 * u * v );
-}
-
 #endif // QGSBILINEARRASTERRESAMPLER_H
