18 #ifndef QGSHILLSHADEFILTER_H    19 #define QGSHILLSHADEFILTER_H    22 #include "qgis_analysis.h"    31     QgsHillshadeFilter( 
const QString &inputFile, 
const QString &outputFile, 
const QString &outputFormat, 
double lightAzimuth = 300,
    32                         double lightAngle = 40 );
    38                                  float *x12, 
float *x22, 
float *x32,
    39                                  float *x13, 
float *x23, 
float *x33 ) 
override;
    42     void setLightAzimuth( 
float azimuth );
    44     void setLightAngle( 
float angle );
    50     const QString openClProgramBaseName()
 const override    52       return QStringLiteral( 
"hillshade" );
    67     void addExtraRasterParams( std::vector<float> ¶ms ) 
override;
    72 #endif // QGSHILLSHADEFILTER_H 
double ANALYSIS_EXPORT angle(QgsPoint *p1, QgsPoint *p2, QgsPoint *p3, QgsPoint *p4)
Calculates the angle between two segments (in 2 dimension, z-values are ignored) 
 
float processNineCellWindow(float *x11, float *x21, float *x31, float *x12, float *x22, float *x32, float *x13, float *x23, float *x33) override=0
Calculates output value from nine input values. 
 
float lightAzimuth() const
 
Adds the ability to calculate derivatives in x- and y-directions.