ClipPainter.h

// SPDX-License-Identifier: LGPL-2.1-or-later
//
// SPDX-FileCopyrightText: 2006-2009 Torsten Rahn <tackat@kde.org>
// SPDX-FileCopyrightText: 2007 Inge Wallin <ingwa@kde.org>
//
 
#ifndef MARBLE_CLIPPAINTER_H
#define MARBLE_CLIPPAINTER_H
 
#include <QPainter>
#include "marble_export.h"
#include "MarbleGlobal.h"
 
class QPaintDevice;
class QPolygonF;
class QPointF;
 
namespace Marble
{
/**
 * @short A QPainter that does viewport clipping for polygons 
 *
 * This class introduces fast polygon/polyline clipping for QPainter
 * to increase the performance.
 * Clipping is accomplished using an algorithm (by Torsten Rahn) that 
 * processes each polyline once. 
 * To keep things fast each possible scenario of two subsequent 
 * points is implemented case by case in a specialized handler which
 * creates interpolated points and helper points.
 */
 
// The reason for this class is a terrible bug in some versions of the
// X Server.  Suppose the widget size is, say, 1000 x 1000 and we have
// a high zoom so that we want to draw a vector from (-100000,
// -100000) to (100000, 100000).  Then the X server will create a
// bitmap that is at least 100000 x 100000 and in the process eat all
// available memory.
//
// So we introduce the ClipPainter that clips all polylines and polygons 
// to the area that is actually visible in the viewport.
//
// @internal
 
class ClipPainterPrivate;
class MARBLE_EXPORT ClipPainter : public QPainter 
{
 public:
    ClipPainter();
    ClipPainter(QPaintDevice*, bool);
 
    ~ClipPainter();
 
    void setScreenClip( bool enable );
    bool hasScreenClip() const;
 
    void drawPolygon( const QPolygonF &, 
                      Qt::FillRule fillRule = Qt::OddEvenFill );
 
    void drawPolyline( const QPolygonF & );
    void drawPolyline( const QPolygonF &, QVector<QPointF>& labelNodes, 
                       LabelPositionFlags labelPositionFlag = LineCenter );
 
    void labelPosition(const QPolygonF &polygon, QVector<QPointF> &labelNodes,
                       LabelPositionFlags labelPositionFlags) const;
 
    void setPen(const QColor &);
    void setPen(const QPen & pen);
    void setPen(Qt::PenStyle style);
    void setBrush(const QBrush & brush);
 
    void setDebugPolygonsLevel( int );
    void setDebugBatchRender( bool );
 
    //  void clearNodeCount(){ m_debugNodeCount = 0; }
    //  int nodeCount(){ return m_debugNodeCount; }
 
 private:
    ClipPainterPrivate * const d;
};
 
}
 
#endif