QGIS API Documentation  3.21.0-Master (909859188c)
qgscontrastenhancement.h
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1 /* **************************************************************************
2  qgscontrastenhancement.h - description
3  -------------------
4 begin : Mon Oct 22 2007
5 copyright : (C) 2007 by Peter J. Ersts
6 email : [email protected]
7 
8 This class contains code that was originally part of the larger QgsRasterLayer
9 class originally created circa 2004 by T.Sutton, Gary E.Sherman, Steve Halasz
10 ****************************************************************************/
11 
12 /* **************************************************************************
13  * *
14  * This program is free software; you can redistribute it and/or modify *
15  * it under the terms of the GNU General Public License as published by *
16  * the Free Software Foundation; either version 2 of the License, or *
17  * (at your option) any later version. *
18  * *
19  ***************************************************************************/
20 
21 #ifndef QGSCONTRASTENHANCEMENT_H
22 #define QGSCONTRASTENHANCEMENT_H
23 
24 #include "qgis_core.h"
25 #include <limits>
26 
27 #include "qgis_sip.h"
28 #include "qgsraster.h"
29 #include <memory>
30 
32 class QDomDocument;
33 class QDomElement;
34 class QString;
35 
42 class CORE_EXPORT QgsContrastEnhancement
43 {
44 
45  public:
46 
49  {
54  UserDefinedEnhancement
55  };
56 
63 
65 
69  static double maximumValuePossible( Qgis::DataType dataType )
70  {
71  switch ( dataType )
72  {
74  return std::numeric_limits<unsigned char>::max();
76  return std::numeric_limits<unsigned short>::max();
78  return std::numeric_limits<short>::max();
80  return std::numeric_limits<unsigned int>::max();
82  return std::numeric_limits<int>::max();
84  return std::numeric_limits<float>::max();
86  return std::numeric_limits<double>::max();
88  return std::numeric_limits<short>::max();
90  return std::numeric_limits<int>::max();
92  return std::numeric_limits<float>::max();
94  return std::numeric_limits<double>::max();
98  // XXX - mloskot: not handled?
99  break;
100  }
101 
102  return std::numeric_limits<double>::max();
103  }
104 
108  static double minimumValuePossible( Qgis::DataType dataType )
109  {
110  switch ( dataType )
111  {
113  return std::numeric_limits<unsigned char>::min();
115  return std::numeric_limits<unsigned short>::min();
117  return std::numeric_limits<short>::min();
119  return std::numeric_limits<unsigned int>::min();
121  return std::numeric_limits<int>::min();
123  return std::numeric_limits<float>::max() * -1.0;
125  return std::numeric_limits<double>::max() * -1.0;
127  return std::numeric_limits<short>::min();
129  return std::numeric_limits<int>::min();
131  return std::numeric_limits<float>::max() * -1.0;
133  return std::numeric_limits<double>::max() * -1.0;
137  // XXX - mloskot: not handled?
138  break;
139  }
140 
141  return std::numeric_limits<double>::max() * -1.0;
142  }
143 
147  static QString contrastEnhancementAlgorithmString( ContrastEnhancementAlgorithm algorithm );
148 
152  static ContrastEnhancementAlgorithm contrastEnhancementAlgorithmFromString( const QString &contrastEnhancementString );
153 
155  double maximumValue() const { return mMaximumValue; }
156 
158  double minimumValue() const { return mMinimumValue; }
159 
160  ContrastEnhancementAlgorithm contrastEnhancementAlgorithm() const { return mContrastEnhancementAlgorithm; }
161 
165  int enhanceContrast( double value );
166 
171  bool isValueInDisplayableRange( double value );
172 
180  void setContrastEnhancementAlgorithm( ContrastEnhancementAlgorithm algorithm, bool generateTable = true );
181 
186  void setContrastEnhancementFunction( QgsContrastEnhancementFunction *function SIP_TRANSFER );
187 
198  void setMaximumValue( double value, bool generateTable = true );
199 
210  void setMinimumValue( double value, bool generateTable = true );
211 
212  void writeXml( QDomDocument &doc, QDomElement &parentElem ) const;
213 
214  void readXml( const QDomElement &elem );
215 
224  void toSld( QDomDocument &doc, QDomElement &element ) const;
225 
226  private:
227 #ifdef SIP_RUN
228  const QgsContrastEnhancement &operator=( const QgsContrastEnhancement & );
229 #endif
230 
232  ContrastEnhancementAlgorithm mContrastEnhancementAlgorithm = NoEnhancement;
233 
235  std::unique_ptr< QgsContrastEnhancementFunction > mContrastEnhancementFunction;
236 
238  bool mEnhancementDirty = false;
239 
241  int *mLookupTable = nullptr;
242 
244  double mMinimumValue;
245 
247  double mMaximumValue;
248 
250  Qgis::DataType mRasterDataType;
251 
253  double mRasterDataTypeRange;
254 
256  double mLookupTableOffset;
257 
259  bool generateLookupTable();
260 
262  int calculateContrastEnhancementValue( double );
263 
264 };
265 
266 #endif
DataType
Raster data types.
Definition: qgis.h:120
@ CInt32
Complex Int32.
@ Float32
Thirty two bit floating point (float)
@ CFloat64
Complex Float64.
@ Int16
Sixteen bit signed integer (qint16)
@ ARGB32_Premultiplied
Color, alpha, red, green, blue, 4 bytes the same as QImage::Format_ARGB32_Premultiplied.
@ UInt16
Sixteen bit unsigned integer (quint16)
@ Byte
Eight bit unsigned integer (quint8)
@ UnknownDataType
Unknown or unspecified type.
@ ARGB32
Color, alpha, red, green, blue, 4 bytes the same as QImage::Format_ARGB32.
@ Int32
Thirty two bit signed integer (qint32)
@ Float64
Sixty four bit floating point (double)
@ CFloat32
Complex Float32.
@ CInt16
Complex Int16.
@ UInt32
Thirty two bit unsigned integer (quint32)
A contrast enhancement function is the base class for all raster contrast enhancements.
Manipulates raster or point cloud pixel values so that they enhanceContrast or clip into a specified ...
ContrastEnhancementAlgorithm
This enumerator describes the types of contrast enhancement algorithms that can be used.
@ StretchToMinimumMaximum
Linear histogram.
@ NoEnhancement
Default color scaling algorithm, no scaling is applied.
static double maximumValuePossible(Qgis::DataType dataType)
Helper function that returns the maximum possible value for a data type.
double minimumValue() const
Returns the minimum value for the contrast enhancement range.
static double minimumValuePossible(Qgis::DataType dataType)
Helper function that returns the minimum possible value for a data type.
const QgsContrastEnhancement & operator=(const QgsContrastEnhancement &)=delete
ContrastEnhancementAlgorithm contrastEnhancementAlgorithm() const
double maximumValue() const
Returns the maximum value for the contrast enhancement range.
As part of the API refactoring and improvements which landed in the Processing API was substantially reworked from the x version This was done in order to allow much of the underlying Processing framework to be ported into allowing algorithms to be written in pure substantial changes are required in order to port existing x Processing algorithms for QGIS x The most significant changes are outlined not GeoAlgorithm For algorithms which operate on features one by consider subclassing the QgsProcessingFeatureBasedAlgorithm class This class allows much of the boilerplate code for looping over features from a vector layer to be bypassed and instead requires implementation of a processFeature method Ensure that your algorithm(or algorithm 's parent class) implements the new pure virtual createInstance(self) call
#define SIP_TRANSFER
Definition: qgis_sip.h:36