QGIS API Documentation  3.13.0-Master (b73bd58cfb)
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  {
50  NoEnhancement, //this should be the default color scaling algorithm
51  StretchToMinimumMaximum, //linear histogram enhanceContrast
54  UserDefinedEnhancement
55  };
56 
60 
61  const QgsContrastEnhancement &operator=( const QgsContrastEnhancement & ) = delete;
62 
66  static double maximumValuePossible( Qgis::DataType dataType )
67  {
68  switch ( dataType )
69  {
70  case Qgis::Byte:
71  return std::numeric_limits<unsigned char>::max();
72  case Qgis::UInt16:
73  return std::numeric_limits<unsigned short>::max();
74  case Qgis::Int16:
75  return std::numeric_limits<short>::max();
76  case Qgis::UInt32:
77  return std::numeric_limits<unsigned int>::max();
78  case Qgis::Int32:
79  return std::numeric_limits<int>::max();
80  case Qgis::Float32:
81  return std::numeric_limits<float>::max();
82  case Qgis::Float64:
83  return std::numeric_limits<double>::max();
84  case Qgis::CInt16:
85  return std::numeric_limits<short>::max();
86  case Qgis::CInt32:
87  return std::numeric_limits<int>::max();
88  case Qgis::CFloat32:
89  return std::numeric_limits<float>::max();
90  case Qgis::CFloat64:
91  return std::numeric_limits<double>::max();
92  case Qgis::ARGB32:
95  // XXX - mloskot: not handled?
96  break;
97  }
98 
99  return std::numeric_limits<double>::max();
100  }
101 
105  static double minimumValuePossible( Qgis::DataType dataType )
106  {
107  switch ( dataType )
108  {
109  case Qgis::Byte:
110  return std::numeric_limits<unsigned char>::min();
111  case Qgis::UInt16:
112  return std::numeric_limits<unsigned short>::min();
113  case Qgis::Int16:
114  return std::numeric_limits<short>::min();
115  case Qgis::UInt32:
116  return std::numeric_limits<unsigned int>::min();
117  case Qgis::Int32:
118  return std::numeric_limits<int>::min();
119  case Qgis::Float32:
120  return std::numeric_limits<float>::max() * -1.0;
121  case Qgis::Float64:
122  return std::numeric_limits<double>::max() * -1.0;
123  case Qgis::CInt16:
124  return std::numeric_limits<short>::min();
125  case Qgis::CInt32:
126  return std::numeric_limits<int>::min();
127  case Qgis::CFloat32:
128  return std::numeric_limits<float>::max() * -1.0;
129  case Qgis::CFloat64:
130  return std::numeric_limits<double>::max() * -1.0;
131  case Qgis::ARGB32:
134  // XXX - mloskot: not handled?
135  break;
136  }
137 
138  return std::numeric_limits<double>::max() * -1.0;
139  }
140 
144  static QString contrastEnhancementAlgorithmString( ContrastEnhancementAlgorithm algorithm );
145 
149  static ContrastEnhancementAlgorithm contrastEnhancementAlgorithmFromString( const QString &contrastEnhancementString );
150 
152  double maximumValue() const { return mMaximumValue; }
153 
155  double minimumValue() const { return mMinimumValue; }
156 
157  ContrastEnhancementAlgorithm contrastEnhancementAlgorithm() const { return mContrastEnhancementAlgorithm; }
158 
162  int enhanceContrast( double value );
163 
168  bool isValueInDisplayableRange( double value );
169 
177  void setContrastEnhancementAlgorithm( ContrastEnhancementAlgorithm algorithm, bool generateTable = true );
178 
183  void setContrastEnhancementFunction( QgsContrastEnhancementFunction *function SIP_TRANSFER );
184 
195  void setMaximumValue( double value, bool generateTable = true );
196 
207  void setMinimumValue( double value, bool generateTable = true );
208 
209  void writeXml( QDomDocument &doc, QDomElement &parentElem ) const;
210 
211  void readXml( const QDomElement &elem );
212 
220  void toSld( QDomDocument &doc, QDomElement &element ) const;
221 
222  private:
223 #ifdef SIP_RUN
224  const QgsContrastEnhancement &operator=( const QgsContrastEnhancement & );
225 #endif
226 
228  ContrastEnhancementAlgorithm mContrastEnhancementAlgorithm = NoEnhancement;
229 
231  std::unique_ptr< QgsContrastEnhancementFunction > mContrastEnhancementFunction;
232 
234  bool mEnhancementDirty = false;
235 
237  int *mLookupTable = nullptr;
238 
240  double mMinimumValue;
241 
243  double mMaximumValue;
244 
246  Qgis::DataType mRasterDataType;
247 
249  double mRasterDataTypeRange;
250 
252  double mLookupTableOffset;
253 
255  bool generateLookupTable();
256 
258  int calculateContrastEnhancementValue( double );
259 
260 };
261 
262 #endif
double maximumValue() const
Returns the maximum value for the contrast enhancement range.
Thirty two bit signed integer (qint32)
Definition: qgis.h:108
static double minimumValuePossible(Qgis::DataType dataType)
Helper function that returns the minimum possible value for a GDAL data type.
static double maximumValuePossible(Qgis::DataType dataType)
Helper function that returns the maximum possible value for a GDAL data type.
Thirty two bit unsigned integer (quint32)
Definition: qgis.h:107
DataType
Raster data types.
Definition: qgis.h:101
double minimumValue() const
Returns the minimum value for the contrast enhancement range.
Thirty two bit floating point (float)
Definition: qgis.h:109
Sixteen bit signed integer (qint16)
Definition: qgis.h:106
Complex Int16.
Definition: qgis.h:111
Sixty four bit floating point (double)
Definition: qgis.h:110
Color, alpha, red, green, blue, 4 bytes the same as QImage::Format_ARGB32_Premultiplied.
Definition: qgis.h:116
Complex Float32.
Definition: qgis.h:113
#define SIP_TRANSFER
Definition: qgis_sip.h:36
Unknown or unspecified type.
Definition: qgis.h:103
Complex Int32.
Definition: qgis.h:112
A contrast enhancement function is the base class for all raster contrast enhancements.
Sixteen bit unsigned integer (quint16)
Definition: qgis.h:105
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
ContrastEnhancementAlgorithm
This enumerator describes the types of contrast enhancement algorithms that can be used...
ContrastEnhancementAlgorithm contrastEnhancementAlgorithm() const
Manipulates raster pixel values so that they enhanceContrast or clip into a specified numerical range...
Complex Float64.
Definition: qgis.h:114
Eight bit unsigned integer (quint8)
Definition: qgis.h:104
Color, alpha, red, green, blue, 4 bytes the same as QImage::Format_ARGB32.
Definition: qgis.h:115