QGIS API Documentation  2.2.0-Valmiera
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qgslinearminmaxenhancement.cpp
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1 /* **************************************************************************
2  qgslinearminmaxenhancement.cpp - description
3  -------------------
4 begin : Fri Nov 16 2007
5 copyright : (C) 2007 by Peter J. Ersts
6 email : [email protected]
7 
8 ****************************************************************************/
9 
10 /* **************************************************************************
11  * *
12  * This program is free software; you can redistribute it and/or modify *
13  * it under the terms of the GNU General Public License as published by *
14  * the Free Software Foundation; either version 2 of the License, or *
15  * (at your option) any later version. *
16  * *
17  ***************************************************************************/
18 
20 
21 QgsLinearMinMaxEnhancement::QgsLinearMinMaxEnhancement( QGis::DataType theQgsRasterDataType, double theMinimumValue, double theMaximumValue ) : QgsContrastEnhancementFunction( theQgsRasterDataType, theMinimumValue, theMaximumValue )
22 {
23 }
24 
26 {
27  int myStretchedValue = static_cast<int>((( theValue - mMinimumValue ) / ( mMinimumMaximumRange ) ) * 255.0 );
28  if ( myStretchedValue < 0 )
29  {
30  return 0;
31  }
32  else if ( myStretchedValue > 255 )
33  {
34  return 255;
35  }
36 
37  return myStretchedValue;
38 }