qgslayoutitemhtml.h

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/***************************************************************************
                              qgslayoutitemhtml.h
    ------------------------------------------------------------
    begin                : October 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 QGSLAYOUTITEMHTML_H
#define QGSLAYOUTITEMHTML_H

#include "qgis_core.h"
#include "qgis_sip.h"
#include "qgslayoutmultiframe.h"
#include "qgsfeature.h"
#include "qgsdistancearea.h"
#include <QUrl>

class QgsWebPage;
class QImage;
class QgsVectorLayer;
class QgsNetworkContentFetcher;

class CORE_EXPORT QgsLayoutItemHtml: public QgsLayoutMultiFrame
{
    Q_OBJECT

  public:

    enum ContentMode
    {
      Url, 
      ManualHtml 
    };

    QgsLayoutItemHtml( QgsLayout *layout SIP_TRANSFERTHIS );

    ~QgsLayoutItemHtml() override;

    int type() const override;
    QIcon icon() const override;

    static QgsLayoutItemHtml *create( QgsLayout *layout ) SIP_FACTORY;

    void setContentMode( ContentMode mode ) { mContentMode = mode; }

    ContentMode contentMode() const { return mContentMode; }

    void setUrl( const QUrl &url );

    QUrl url() const { return mUrl; }

    void setHtml( const QString &html );

    QString html() const { return mHtml; }

    bool evaluateExpressions() const { return mEvaluateExpressions; }

    void setEvaluateExpressions( bool evaluateExpressions );

    bool useSmartBreaks() const { return mUseSmartBreaks; }

    void setUseSmartBreaks( bool useSmartBreaks );

    void setMaxBreakDistance( double distance );

    double maxBreakDistance() const { return mMaxBreakDistance; }

    void setUserStylesheet( const QString &stylesheet );

    QString userStylesheet() const { return mUserStylesheet; }

    void setUserStylesheetEnabled( bool enabled );

    bool userStylesheetEnabled() const { return mEnableUserStylesheet; }

    QString displayName() const override;
    QSizeF totalSize() const override;
    void render( QgsLayoutItemRenderContext &context, const QRectF &renderExtent, int frameIndex ) override;

    //overridden to break frames without dividing lines of text
    double findNearbyPageBreak( double yPos ) override;

  public slots:

    void loadHtml( bool useCache = false, const QgsExpressionContext *context = nullptr );

    void recalculateFrameSizes() override;

    void refreshDataDefinedProperty( QgsLayoutObject::DataDefinedProperty property = QgsLayoutObject::AllProperties ) override;

  protected:

    bool writePropertiesToElement( QDomElement &elem, QDomDocument &doc, const QgsReadWriteContext &context ) const override;
    bool readPropertiesFromElement( const QDomElement &itemElem, const QDomDocument &doc, const QgsReadWriteContext &context ) override;

  private:
    ContentMode mContentMode = QgsLayoutItemHtml::Url;
    QUrl mUrl;
    std::unique_ptr< QgsWebPage > mWebPage;
    QString mHtml;
    QString mFetchedHtml;
    QString mLastFetchedUrl;
    QString mActualFetchedUrl; //may be different if page was redirected
    QSizeF mSize; //total size in mm
    double mHtmlUnitsToLayoutUnits = 1.0;
    QImage mRenderedPage;
    bool mEvaluateExpressions = true;
    bool mUseSmartBreaks = true;
    double mMaxBreakDistance = 10.0;

    QgsFeature mExpressionFeature;
    QgsVectorLayer *mExpressionLayer = nullptr;
    QgsDistanceArea mDistanceArea;

    QString mUserStylesheet;
    bool mEnableUserStylesheet = false;

    QString mAtlasFeatureJSON;

    QgsNetworkContentFetcher *mFetcher = nullptr;

    double htmlUnitsToLayoutUnits(); //calculate scale factor

    //renders a snapshot of the page to a cached image
    void renderCachedImage();

    //fetches html content from a url and returns it as a string
    QString fetchHtml( const QUrl &url );

    void setExpressionContext( const QgsFeature &feature, QgsVectorLayer *layer );

    double maxFrameWidth() const;

    void refreshExpressionContext();
};

#ifndef SIP_RUN
class JavascriptExecutorLoop : public QEventLoop
{
    Q_OBJECT
  public slots:

    void done();
    void execIfNotDone();
    void reportError( const QString &error );

  private:

    bool mDone = false;

};
#endif

#endif // QGSLAYOUTITEMHTML_H