Keep image aspect in bilinear resampling, apply oversampling for zoom out

mhugent · mhugent · commit 2883fbc5ba1d · 2012-01-14T14:44:35.000+01:00
diff --git a/src/core/raster/qgsbilinearrasterresampler.cpp b/src/core/raster/qgsbilinearrasterresampler.cpp
@@ -29,5 +29,5 @@ QgsBilinearRasterResampler::~QgsBilinearRasterResampler()
 
 void QgsBilinearRasterResampler::resample( const QImage& srcImage, QImage& dstImage )
 {
-  dstImage = srcImage.scaled( dstImage.width(), dstImage.height(), Qt::IgnoreAspectRatio, Qt::SmoothTransformation );
+  dstImage = srcImage.scaled( dstImage.width(), dstImage.height(), Qt::KeepAspectRatio, Qt::SmoothTransformation );
 }
diff --git a/src/core/raster/qgsrasterrenderer.cpp b/src/core/raster/qgsrasterrenderer.cpp
@@ -59,7 +59,7 @@ void QgsRasterRenderer::startRasterRead( int bandNumber, QgsRasterViewPort* view
       providerExtent = t.transformBoundingBox( providerExtent );
     }
     double pixelRatio = mapToPixel->mapUnitsPerPixel() / ( providerExtent.width() / mProvider->xSize() );
-    oversampling = pixelRatio > 1.0 ? 1.0 : pixelRatio;
+    oversampling = ( pixelRatio > 4.0 ) ? 4.0 : pixelRatio;
   }
 
   //split raster into small portions if necessary

Original file line number	Diff line number	Diff line change
`@@ -29,5 +29,5 @@ QgsBilinearRasterResampler::~QgsBilinearRasterResampler()`
`29`	`29`
`30`	`30`	`void QgsBilinearRasterResampler::resample( const QImage& srcImage, QImage& dstImage )`
`31`	`31`	`{`
`32`		`- dstImage = srcImage.scaled( dstImage.width(), dstImage.height(), Qt::IgnoreAspectRatio, Qt::SmoothTransformation );`
	`32`	`+ dstImage = srcImage.scaled( dstImage.width(), dstImage.height(), Qt::KeepAspectRatio, Qt::SmoothTransformation );`
`33`	`33`	`}`
Original file line number	Diff line number	Diff line change
`@@ -59,7 +59,7 @@ void QgsRasterRenderer::startRasterRead( int bandNumber, QgsRasterViewPort* view`
`59`	`59`	`providerExtent = t.transformBoundingBox( providerExtent );`
`60`	`60`	`}`
`61`	`61`	`double pixelRatio = mapToPixel->mapUnitsPerPixel() / ( providerExtent.width() / mProvider->xSize() );`
`62`		`- oversampling = pixelRatio > 1.0 ? 1.0 : pixelRatio;`
	`62`	`+ oversampling = ( pixelRatio > 4.0 ) ? 4.0 : pixelRatio;`
`63`	`63`	`}`
`64`	`64`
`65`	`65`	`//split raster into small portions if necessary`