gdal slow rendering when zoomed in fix

rblazek · rblazek · commit d5febb5407c9 · 2011-04-15T11:21:41.000Z
git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@15702 c8812cc2-4d05-0410-92ff-de0c093fc19c
diff --git a/src/providers/gdal/qgsgdalprovider.cpp b/src/providers/gdal/qgsgdalprovider.cpp
@@ -691,10 +691,11 @@ void QgsGdalProvider::readBlock( int theBandNo, QgsRectangle  const & theExtent,
   {
     tmpWidth = static_cast<int>( qRound( srcWidth * srcXRes / xRes ) ) ;
   }
-  if ( yRes > srcYRes )
+  if ( yRes > fabs( srcYRes ) )
   {
     tmpHeight = static_cast<int>( qRound( -1.*srcHeight * srcYRes / yRes ) ) ;
   }
+
   double tmpXMin = mExtent.xMinimum() + srcLeft * srcXRes;
   double tmpYMax = mExtent.yMaximum() + srcTop * srcYRes;
   QgsDebugMsg( QString( "tmpXMin = %1 tmpYMax = %2 tmpWidth = %3 tmpHeight = %4" ).arg( tmpXMin ).arg( tmpYMax ).arg( tmpWidth ).arg( tmpHeight ) );

Original file line number	Diff line number	Diff line change
`@@ -691,10 +691,11 @@ void QgsGdalProvider::readBlock( int theBandNo, QgsRectangle const & theExtent,`
`691`	`691`	`{`
`692`	`692`	`tmpWidth = static_cast<int>( qRound( srcWidth * srcXRes / xRes ) ) ;`
`693`	`693`	`}`
`694`		`- if ( yRes > srcYRes )`
	`694`	`+ if ( yRes > fabs( srcYRes ) )`
`695`	`695`	`{`
`696`	`696`	`tmpHeight = static_cast<int>( qRound( -1.srcHeight srcYRes / yRes ) ) ;`
`697`	`697`	`}`
	`698`	`+`
`698`	`699`	`double tmpXMin = mExtent.xMinimum() + srcLeft * srcXRes;`
`699`	`700`	`double tmpYMax = mExtent.yMaximum() + srcTop * srcYRes;`
`700`	`701`	`QgsDebugMsg( QString( "tmpXMin = %1 tmpYMax = %2 tmpWidth = %3 tmpHeight = %4" ).arg( tmpXMin ).arg( tmpYMax ).arg( tmpWidth ).arg( tmpHeight ) );`