qgspainteffect.h

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/***************************************************************************
                             qgspainteffect.h
                             ----------------
    begin                : December 2014
    copyright            : (C) 2014 Nyall Dawson
    email                : nyall dot dawson at gmail dot com
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   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 QGSPAINTEFFECT_H
#define QGSPAINTEFFECT_H

#include "qgis_core.h"
#include "qgis.h"
#include <QPainter>
#include <QDomDocument>
#include <QDomElement>

class QgsRenderContext;

class CORE_EXPORT QgsPaintEffect
{

#ifdef SIP_RUN
    SIP_CONVERT_TO_SUBCLASS_CODE
    if ( sipCpp->type() == "drawSource" && dynamic_cast<QgsDrawSourceEffect *>( sipCpp ) != NULL )
    {
      sipType = sipType_QgsDrawSourceEffect;
    }
    else if ( sipCpp->type() == "effectStack" && dynamic_cast<QgsEffectStack *>( sipCpp ) != NULL )
    {
      sipType = sipType_QgsEffectStack;
    }
    else if ( sipCpp->type() == "blur" && dynamic_cast<QgsBlurEffect *>( sipCpp ) != NULL )
    {
      sipType = sipType_QgsBlurEffect;
    }
    else if ( sipCpp->type() == "dropShadow" && dynamic_cast<QgsDropShadowEffect *>( sipCpp ) != NULL )
    {
      sipType = sipType_QgsDropShadowEffect;
    }
    else if ( sipCpp->type() == "outerGlow" && dynamic_cast<QgsOuterGlowEffect *>( sipCpp ) != NULL )
    {
      sipType = sipType_QgsOuterGlowEffect;
    }
    else if ( sipCpp->type() == "innerGlow" && dynamic_cast<QgsInnerGlowEffect *>( sipCpp ) != NULL )
    {
      sipType = sipType_QgsInnerGlowEffect;
    }
    else if ( sipCpp->type() == "transform" && dynamic_cast<QgsTransformEffect *>( sipCpp ) != NULL )
    {
      sipType = sipType_QgsTransformEffect;
    }
    else if ( sipCpp->type() == "color" && dynamic_cast<QgsColorEffect *>( sipCpp ) != NULL )
    {
      sipType = sipType_QgsColorEffect;
    }
    else
    {
      sipType = 0;
    }
    SIP_END
#endif

  public:

    enum DrawMode
    {
      Modifier, 
      Render, 
      ModifyAndRender 
    };

    QgsPaintEffect() = default;

    QgsPaintEffect( const QgsPaintEffect &other );
    virtual ~QgsPaintEffect();

    virtual QString type() const = 0;

    virtual QgsPaintEffect *clone() const = 0 SIP_FACTORY;

    virtual QgsStringMap properties() const = 0;

    virtual void readProperties( const QgsStringMap &props ) = 0;

    virtual bool saveProperties( QDomDocument &doc, QDomElement &element ) const;

    virtual bool readProperties( const QDomElement &element );

    virtual void render( QPicture &picture, QgsRenderContext &context );

    virtual void begin( QgsRenderContext &context );

    virtual void end( QgsRenderContext &context );

    bool enabled() const { return mEnabled; }

    void setEnabled( const bool enabled );

    DrawMode drawMode() const { return mDrawMode; }

    void setDrawMode( const DrawMode drawMode );

  protected:

    bool mEnabled = true;
    DrawMode mDrawMode = ModifyAndRender;
    bool requiresQPainterDpiFix = true;

    virtual void draw( QgsRenderContext &context ) = 0;

    void drawSource( QPainter &painter );

    const QPicture *source() const { return mPicture; }

    QImage *sourceAsImage( QgsRenderContext &context );

    QPointF imageOffset( const QgsRenderContext &context ) const;

    virtual QRectF boundingRect( const QRectF &rect, const QgsRenderContext &context ) const;

    void fixQPictureDpi( QPainter *painter ) const;

  private:

    const QPicture *mPicture = nullptr;
    QImage *mSourceImage = nullptr;
    bool mOwnsImage = false;

    QPainter *mPrevPainter = nullptr;
    QPainter *mEffectPainter = nullptr;
    QPicture *mTempPicture = nullptr;

    QRectF imageBoundingRect( const QgsRenderContext &context ) const;

    friend class QgsEffectStack;

};

class CORE_EXPORT QgsDrawSourceEffect : public QgsPaintEffect
{
  public:

    QgsDrawSourceEffect() = default;

    static QgsPaintEffect *create( const QgsStringMap &map ) SIP_FACTORY;

    QString type() const override { return QStringLiteral( "drawSource" ); }
    QgsDrawSourceEffect *clone() const override SIP_FACTORY;
    QgsStringMap properties() const override;
    void readProperties( const QgsStringMap &props ) override;

    void setOpacity( const double opacity ) { mOpacity = opacity; }

    double opacity() const { return mOpacity; }

    void setBlendMode( const QPainter::CompositionMode mode ) { mBlendMode = mode; }

    QPainter::CompositionMode blendMode() const { return mBlendMode; }

  protected:

    void draw( QgsRenderContext &context ) override;

  private:

    double mOpacity = 1.0;
    QPainter::CompositionMode mBlendMode = QPainter::CompositionMode_SourceOver;
};

class CORE_EXPORT QgsEffectPainter
{
  public:

    QgsEffectPainter( QgsRenderContext &renderContext );

    QgsEffectPainter( QgsRenderContext &renderContext, QgsPaintEffect *effect );
    ~QgsEffectPainter();

    void setEffect( QgsPaintEffect *effect );


    QPainter *operator->() { return mPainter; }

  private:
    QgsRenderContext &mRenderContext;
    QPainter *mPainter = nullptr;
    QgsPaintEffect *mEffect = nullptr;
};

#endif // QGSPAINTEFFECT_H