qgsvectorfieldsymbollayer.h

/***************************************************************************
         qgsvectorfieldsymbollayer.h
         -------------------------
  begin                : Octorer 25, 2011
  copyright            : (C) 2011 by Marco Hugentobler
  email                : marco dot hugentobler at sourcepole dot ch
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   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 QGSVECTORFIELDSYMBOLLAYER_H
#define QGSVECTORFIELDSYMBOLLAYER_H

#include "qgis_core.h"
#include "qgis.h"
#include "qgssymbollayer.h"

/**
 * \ingroup core
 * A symbol layer class for displaying displacement arrows based on point layer attributes*/
class CORE_EXPORT QgsVectorFieldSymbolLayer: public QgsMarkerSymbolLayer
{
  public:
    enum VectorFieldType
    {
      Cartesian = 0,
      Polar,
      Height
    };

    enum AngleOrientation
    {
      ClockwiseFromNorth = 0,
      CounterclockwiseFromEast
    };

    enum AngleUnits
    {
      Degrees = 0,
      Radians
    };

    QgsVectorFieldSymbolLayer();

    static QgsSymbolLayer *create( const QgsStringMap &properties = QgsStringMap() );
    static QgsSymbolLayer *createFromSld( QDomElement &element );

    QString layerType() const override { return QStringLiteral( "VectorField" ); }

    bool setSubSymbol( QgsSymbol *symbol SIP_TRANSFER ) override;
    QgsSymbol *subSymbol() override { return mLineSymbol.get(); }

    void setColor( const QColor &color ) override;
    QColor color() const override;

    void renderPoint( QPointF point, QgsSymbolRenderContext &context ) override;
    void startRender( QgsSymbolRenderContext &context ) override;
    void stopRender( QgsSymbolRenderContext &context ) override;

    QgsVectorFieldSymbolLayer *clone() const override SIP_FACTORY;
    QgsStringMap properties() const override;

    void toSld( QDomDocument &doc, QDomElement &element, const QgsStringMap &props ) const override;

    void drawPreviewIcon( QgsSymbolRenderContext &context, QSize size ) override;

    QSet<QString> usedAttributes( const QgsRenderContext &context ) const override;
    bool hasDataDefinedProperties() const override;

    //setters and getters
    void setXAttribute( const QString &attribute ) { mXAttribute = attribute; }
    QString xAttribute() const { return mXAttribute; }
    void setYAttribute( const QString &attribute ) { mYAttribute = attribute; }
    QString yAttribute() const { return mYAttribute; }
    void setScale( double s ) { mScale = s; }
    double scale() const { return mScale; }
    void setVectorFieldType( VectorFieldType type ) { mVectorFieldType = type; }
    VectorFieldType vectorFieldType() const { return mVectorFieldType; }
    void setAngleOrientation( AngleOrientation orientation ) { mAngleOrientation = orientation; }
    AngleOrientation angleOrientation() const { return mAngleOrientation; }
    void setAngleUnits( AngleUnits units ) { mAngleUnits = units; }
    AngleUnits angleUnits() const { return mAngleUnits; }

    void setOutputUnit( QgsUnitTypes::RenderUnit unit ) override;
    QgsUnitTypes::RenderUnit outputUnit() const override;

    void setMapUnitScale( const QgsMapUnitScale &scale ) override;
    QgsMapUnitScale mapUnitScale() const override;

    /**
     * Sets the units for the distance.
     * \param unit distance units
     * \see distanceUnit()
    */
    void setDistanceUnit( QgsUnitTypes::RenderUnit unit ) { mDistanceUnit = unit; }

    /**
     * Returns the units for the distance.
     * \see setDistanceUnit()
    */
    QgsUnitTypes::RenderUnit distanceUnit() const { return mDistanceUnit; }

    void setDistanceMapUnitScale( const QgsMapUnitScale &scale ) { mDistanceMapUnitScale = scale; }
    const QgsMapUnitScale &distanceMapUnitScale() const { return mDistanceMapUnitScale; }

    // TODO - implement properly
    QRectF bounds( QPointF, QgsSymbolRenderContext & ) override { return QRectF(); }

  private:
#ifdef SIP_RUN
    QgsVectorFieldSymbolLayer( const QgsVectorFieldSymbolLayer &other );
#endif

    QString mXAttribute;
    QString mYAttribute;
    QgsUnitTypes::RenderUnit mDistanceUnit = QgsUnitTypes::RenderMillimeters;
    QgsMapUnitScale mDistanceMapUnitScale;
    double mScale = 1.0;
    VectorFieldType mVectorFieldType = Cartesian;
    AngleOrientation mAngleOrientation = ClockwiseFromNorth;
    AngleUnits mAngleUnits = Degrees;

    std::unique_ptr< QgsLineSymbol > mLineSymbol;

    //Attribute indices are resolved in startRender method
    int mXIndex = -1;
    int mYIndex = -1;

    //Converts length/angle to Cartesian x/y
    void convertPolarToCartesian( double length, double angle, double &x, double &y ) const;
};

#endif // QGSVECTORFIELDSYMBOLLAYER_H