QGIS/src/core/layout/qgslayoutrendercontext.h

/***************************************************************************
                             qgslayoutrendercontext.h
                             -------------------
    begin                : July 2017
    copyright            : (C) 2017 by 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 QGSLAYOUTRENDERCONTEXT_H
#define QGSLAYOUTRENDERCONTEXT_H

#include "qgis_core.h"
#include "qgslayoutmeasurementconverter.h"
#include "qgsrendercontext.h"
#include <QtGlobal>

class QgsLayout;

/**
 * \ingroup core
 * \class QgsLayoutRenderContext
 * \brief Stores information relating to the current rendering settings for a layout.
 * \since QGIS 3.0
 */
class CORE_EXPORT QgsLayoutRenderContext : public QObject
{

    Q_OBJECT

  public:

    //! Flags for controlling how a layout is rendered
    enum Flag
    {
      FlagDebug = 1 << 1,  //!< Debug/testing mode, items are drawn as solid rectangles.
      FlagOutlineOnly = 1 << 2, //!< Render items as outlines only.
      FlagAntialiasing = 1 << 3, //!< Use antialiasing when drawing items.
      FlagUseAdvancedEffects = 1 << 4, //!< Enable advanced effects such as blend modes.
      FlagForceVectorOutput = 1 << 5, //!< Force output in vector format where possible, even if items require rasterization to keep their correct appearance.
      FlagHideCoverageLayer = 1 << 6, //!< Hide coverage layer in outputs
    };
    Q_DECLARE_FLAGS( Flags, Flag )

    /**
     * Constructor for QgsLayoutRenderContext.
     */
    QgsLayoutRenderContext( QgsLayout *layout SIP_TRANSFERTHIS );

    /**
     * Sets the combination of \a flags that will be used for rendering the layout.
     * \see setFlag()
     * \see flags()
     * \see testFlag()
     */
    void setFlags( const QgsLayoutRenderContext::Flags flags );

    /**
     * Enables or disables a particular rendering \a flag for the layout. Other existing
     * flags are not affected.
     * \see setFlags()
     * \see flags()
     * \see testFlag()
     */
    void setFlag( const QgsLayoutRenderContext::Flag flag, const bool on = true );

    /**
     * Returns the current combination of flags used for rendering the layout.
     * \see setFlags()
     * \see setFlag()
     * \see testFlag()
     */
    QgsLayoutRenderContext::Flags flags() const;

    /**
     * Check whether a particular rendering \a flag is enabled for the layout.
     * \see setFlags()
     * \see setFlag()
     * \see flags()
     */
    bool testFlag( const Flag flag ) const;

    /**
     * Returns the combination of render context flags matched to the layout context's settings.
     */
    QgsRenderContext::Flags renderContextFlags() const;

    /**
     * Sets the \a dpi for outputting the layout. This also sets the
     * corresponding DPI for the context's measurementConverter().
     * \see dpi()
     */
    void setDpi( double dpi );

    /**
     * Returns the \a dpi for outputting the layout.
     * \see setDpi()
     */
    double dpi() const;

    /**
     * Returns the layout measurement converter to be used in the layout. This converter is used
     * for translating between other measurement units and the layout's native unit.
     */
    SIP_SKIP const QgsLayoutMeasurementConverter &measurementConverter() const { return mMeasurementConverter; }

    /**
     * Returns the layout measurement converter to be used in the layout. This converter is used
     * for translating between other measurement units and the layout's native unit.
     */
    QgsLayoutMeasurementConverter &measurementConverter() { return mMeasurementConverter; }

    /**
     * Returns true if the render current being conducted is a preview render,
     * i.e. it is being rendered inside a QGraphicsView widget as opposed to a destination
     * device (such as an image).
     */
    bool isPreviewRender() const { return mIsPreviewRender; }

    /**
     * Returns true if the page grid should be drawn.
     * \see setGridVisible()
     */
    bool gridVisible() const;

    /**
     * Sets whether the page grid should be \a visible.
     * \see gridVisible()
     */
    void setGridVisible( bool visible );

    /**
     * Returns true if the item bounding boxes should be drawn.
     * \see setBoundingBoxesVisible()
     */
    bool boundingBoxesVisible() const;

    /**
     * Sets whether the item bounding boxes should be \a visible.
     * \see boundingBoxesVisible()
     */
    void setBoundingBoxesVisible( bool visible );

    /**
     * Sets whether the page items should be \a visible in the layout. Removing
     * them will prevent both display of the page boundaries in layout views and
     * will also prevent them from being rendered in layout exports.
     * \see pagesVisible()
     */
    void setPagesVisible( bool visible );

    /**
     * Returns whether the page items are be visible in the layout. This setting
     * effects both display of the page boundaries in layout views and
     * whether they will be rendered in layout exports.
     * \see setPagesVisible()
     */
    bool pagesVisible() const { return mPagesVisible; }

    /**
     * Sets the current item \a layer to draw while exporting. QgsLayoutItem subclasses
     * which support multi-layer SVG exports must check the currentExportLayer()
     * and customise their rendering based on the layer.
     *
     * If \a layer is -1, all item layers will be rendered.
     *
     * \see currentExportLayer()
     */
    void setCurrentExportLayer( int layer = -1 ) { mCurrentExportLayer = layer; }

    /**
     * Returns the current item layer to draw while exporting. QgsLayoutItem subclasses
     * which support multi-layer SVG exports must check this
     * and customise their rendering based on the layer.
     *
     * If \a layer is -1, all item layers should be rendered.
     *
     * \see setCurrentExportLayer()
     */
    int currentExportLayer() const { return mCurrentExportLayer; }

  signals:

    /**
     * Emitted whenever the context's \a flags change.
     * \see setFlags()
     */
    void flagsChanged( QgsLayoutRenderContext::Flags flags );

    /**
     * Emitted when the context's DPI is changed.
     */
    void dpiChanged();

  private:

    Flags mFlags = nullptr;

    QgsLayout *mLayout = nullptr;

    int mCurrentExportLayer = -1;

    QgsLayoutMeasurementConverter mMeasurementConverter;

    bool mIsPreviewRender = true;
    bool mGridVisible = false;
    bool mBoundingBoxesVisible = true;
    bool mPagesVisible = true;

    friend class QgsLayoutExporter;
    friend class TestQgsLayout;
    friend class LayoutContextPreviewSettingRestorer;

};

Q_DECLARE_METATYPE( QgsLayoutRenderContext::Flags )

#endif //QGSLAYOUTRENDERCONTEXT_H