painterrenderer.h

/*
    SPDX-FileCopyrightText: 2020 Volker Krause <vkrause@kde.org>
 
    SPDX-License-Identifier: LGPL-2.0-or-later
*/
 
#ifndef KOSMINDOORMAP_PAINTERRENDERER_H
#define KOSMINDOORMAP_PAINTERRENDERER_H
 
#include "kosmindoormap_export.h"
 
#include <KOSMIndoorMap/SceneGraphItem>
 
class QPainter;
 
namespace KOSMIndoorMap {
 
class SceneGraph;
class View;
 
/** QPainter-based renderer of a SceneGraph.
 *  Trying to keep this somewhat backend-agnostic to possibly implement a 3D renderer in the future.
 */
class KOSMINDOORMAP_EXPORT PainterRenderer
{
public:
    explicit PainterRenderer();
    ~PainterRenderer();
 
    void setPainter(QPainter *painter);
    void render(const SceneGraph &sg, View *view);
 
private:
    void beginRender();
    void beginPhase(SceneGraphItemPayload::RenderPhase phase);
    void prepareBatch(SceneGraphItemPayload::RenderPhase phase);
    void renderBackground(const QColor &bgColor);
    void renderPolygon(PolygonItem *item, SceneGraphItemPayload::RenderPhase phase);
    void renderMultiPolygon(MultiPolygonItem *item, SceneGraphItemPayload::RenderPhase phase);
    void renderPolyline(PolylineItem *item, SceneGraphItemPayload::RenderPhase phase);
    void renderLabel(LabelItem *item, SceneGraphItemPayload::RenderPhase phase);
    void renderForeground(const QColor &bgColor);
    void endRender();
 
    template <typename T>
    void renderPolygonFill(PolygonBaseItem *item, const T &geom);
    template <typename T>
    void renderPolygonLine(PolygonBaseItem *item, const T &geom);
    template <typename T>
    void renderPolygonCasing(PolygonBaseItem *item, const T &geom);
 
    [[nodiscard]] double mapToSceneWidth(double width, Unit unit) const;
    [[nodiscard]] double mapToScreenWidth(double width, Unit unit) const;
    // inverse view transformation with translation applied
    // needed for textured brushes
    [[nodiscard]] QTransform brushTransform() const;
 
    QPainter *m_painter = nullptr;
    View *m_view = nullptr;
 
    std::vector<SceneGraphItemPayload*> m_renderBatch; // member rather than function-local to preserve allocations
};
 
}
 
#endif // KOSMINDOORMAP_PAINTERRENDERER_H