QGIS API Documentation 3.27.0-Master (c6eca784ad)
qgscontrastenhancement.h
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1/* **************************************************************************
2 qgscontrastenhancement.h - description
3 -------------------
4begin : Mon Oct 22 2007
5copyright : (C) 2007 by Peter J. Ersts
7
8This class contains code that was originally part of the larger QgsRasterLayer
9class 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
32class QDomDocument;
33class QDomElement;
34class QString;
35
42class 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:129
@ 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