fall to precise reprojection if thresh wasnt reached

git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@15697 c8812cc2-4d05-0410-92ff-de0c093fc19c
qgis · Apr 13, 2011 · 0e0909b · 0e0909b
1 parent 45cbf9f
commit 0e0909b
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diff --git a/src/core/qgsrasterprojector.cpp b/src/core/qgsrasterprojector.cpp
@@ -80,13 +80,15 @@ QgsRasterProjector::QgsRasterProjector(
     if ( myColsOK && myRowsOK )
     {
       QgsDebugMsg( "CP matrix within tolerance" );
+      mApproximate = true;
       break;
     }
     // What is the maximum reasonable size of transformatio matrix?
     // TODO: consider better when to break - ratio
     if ( mCPRows * mCPCols > 0.25 * mDestRows * mDestCols )
     {
       QgsDebugMsg( "Too large CP matrix" );
+      mApproximate = false;
       break;
     }
 
@@ -292,6 +294,29 @@ void QgsRasterProjector::nextHelper()
 }
 
 void QgsRasterProjector::srcRowCol( int theDestRow, int theDestCol, int *theSrcRow, int *theSrcCol )
+{
+  if ( mApproximate ) approximateSrcRowCol( theDestRow, theDestCol, theSrcRow, theSrcCol);
+  else preciseSrcRowCol( theDestRow, theDestCol, theSrcRow, theSrcCol);
+}
+
+void QgsRasterProjector::preciseSrcRowCol( int theDestRow, int theDestCol, int *theSrcRow, int *theSrcCol )
+{
+  // Get coordinate of center of destination cell
+  double x = mDestExtent.xMinimum() + ( theDestCol + 0.5 ) * mDestXRes;
+  double y = mDestExtent.yMaximum() - ( theDestRow + 0.5 ) * mDestYRes;
+  double z = 0;
+
+  mCoordinateTransform.transformInPlace( x, y, z );
+
+  // Get source row col
+  *theSrcRow = ( int ) floor(( mSrcExtent.yMaximum() - y ) / mSrcXRes );
+  *theSrcCol = ( int ) floor(( x - mSrcExtent.xMinimum() ) / mSrcYRes );
+
+  assert( *theSrcRow < mSrcRows );
+  assert( *theSrcCol < mSrcCols );
+}
+
+void QgsRasterProjector::approximateSrcRowCol( int theDestRow, int theDestCol, int *theSrcRow, int *theSrcCol )
 {
   int myMatrixRow = matrixRow( theDestRow );
   int myMatrixCol = matrixCol( theDestCol );

diff --git a/src/core/qgsrasterprojector.h b/src/core/qgsrasterprojector.h
@@ -69,6 +69,12 @@ class QgsRasterProjector
     /** \brief get destination point for _current_ matrix position */
     QgsPoint srcPoint( int theRow, int theCol );
 
+    /** \brief Get precise source row and column indexes for current source extent and resolution */
+    inline void preciseSrcRowCol( int theDestRow, int theDestCol, int *theSrcRow, int *theSrcCol );
+
+    /** \brief Get approximate source row and column indexes for current source extent and resolution */
+    inline void approximateSrcRowCol( int theDestRow, int theDestCol, int *theSrcRow, int *theSrcCol );
+
     /** \brief Get source row and column indexes for current source extent and resolution */
     void srcRowCol( int theDestRow, int theDestCol, int *theSrcRow, int *theSrcCol );
 
@@ -194,6 +200,9 @@ class QgsRasterProjector
     /** Maximum source resolution */
     double mMaxSrcXRes;
     double mMaxSrcYRes;
+
+    /** Use approximation */
+    bool mApproximate;
 };
 
 #endif