qgscolorrampshader.h

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/* **************************************************************************
                qgscolorrampshader.h -  description
                       -------------------
begin                : Fri Dec 28 2007
copyright            : (C) 2007 by Peter J. Ersts
email                : [email protected]

This class is based off of code that was originally written by Marco Hugentobler and
originally part of the larger QgsRasterLayer class
****************************************************************************/

/* **************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

#ifndef QGSCOLORRAMPSHADER_H
#define QGSCOLORRAMPSHADER_H

#include "qgis_core.h"
#include "qgis_sip.h"
#include <QColor>
#include <QVector>
#include <memory>

#include "qgscolorramp.h"
#include "qgsrasterinterface.h"
#include "qgsrastershaderfunction.h"
#include "qgsrectangle.h"

class CORE_EXPORT QgsColorRampShader : public QgsRasterShaderFunction
{

  public:

    enum Type
    {
      Interpolated, 
      Discrete,     
      Exact         
    };

    enum ClassificationMode
    {
      Continuous = 1, 
      EqualInterval = 2, 
      Quantile = 3 
    };

    QgsColorRampShader( double minimumValue = 0.0, double maximumValue = 255.0, QgsColorRamp *colorRamp SIP_TRANSFER = nullptr, Type type = Interpolated, ClassificationMode classificationMode = Continuous );

    QgsColorRampShader( const QgsColorRampShader &other );

    QgsColorRampShader &operator=( const QgsColorRampShader &other );

    //An entry for classification based upon value.
    //Such a classification is typically used for
    //single band layers where a pixel value represents
    //not a color but a quantity, e.g. temperature or elevation
    struct ColorRampItem
    {
      ColorRampItem() = default;
      ColorRampItem( double val, const QColor &col, const QString &lbl = QString() )
        : label( lbl )
        , value( val )
        , color( col )
      {}

      QString label;
      double value = 0;
      QColor color;

      // compare operator for sorting
      bool operator<( const QgsColorRampShader::ColorRampItem &other ) const { return value < other.value; }
    };

    QList<QgsColorRampShader::ColorRampItem> colorRampItemList() const { return mColorRampItemList.toList(); }

    Type colorRampType() const { return mColorRampType; }

    QString colorRampTypeAsQString() const;

    void setColorRampItemList( const QList<QgsColorRampShader::ColorRampItem> &list ); //TODO: sort on set

    void setColorRampType( QgsColorRampShader::Type colorRampType );

    bool isEmpty() const;

    QgsColorRamp *sourceColorRamp() const SIP_FACTORY;

    void setSourceColorRamp( QgsColorRamp *colorramp SIP_TRANSFER );

    void setColorRampType( const QString &type );

    void classifyColorRamp( int classes = 0, int band = -1, const QgsRectangle &extent = QgsRectangle(), QgsRasterInterface *input = nullptr );

    void classifyColorRamp( int band = -1, const QgsRectangle &extent = QgsRectangle(), QgsRasterInterface *input = nullptr ) SIP_PYNAME( classifyColorRampV2 );

    bool shade( double value, int *returnRedValue SIP_OUT, int *returnGreenValue SIP_OUT, int *returnBlueValue SIP_OUT, int *returnAlphaValue SIP_OUT ) const override;

    bool shade( double redValue, double greenValue,
                double blueValue, double alphaValue,
                int *returnRedValue SIP_OUT, int *returnGreenValue SIP_OUT,
                int *returnBlueValue SIP_OUT, int *returnAlphaValue SIP_OUT ) const override;

    void legendSymbologyItems( QList< QPair< QString, QColor > > &symbolItems SIP_OUT ) const override;

    QDomElement writeXml( QDomDocument &doc ) const;

    void readXml( const QDomElement &elem );

    void setClassificationMode( ClassificationMode classificationMode ) { mClassificationMode = classificationMode; }

    ClassificationMode classificationMode() const { return mClassificationMode; }

    void setClip( bool clip ) { mClip = clip; }

    bool clip() const { return mClip; }

  protected:

    std::unique_ptr<QgsColorRamp> mSourceColorRamp;

  private:

    QVector<QgsColorRampShader::ColorRampItem> mColorRampItemList;

    Type mColorRampType;
    ClassificationMode mClassificationMode;

    mutable QVector<int> mLUT;
    mutable double mLUTOffset = 0.0;
    mutable double mLUTFactor = 1.0;
    mutable bool mLUTInitialized = false;

    bool mClip = false;
};

#endif