qgssvgcache.h

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/***************************************************************************
                              qgssvgcache.h
                            ------------------------------
  begin                :  2011
  copyright            : (C) 2011 by Marco Hugentobler
  email                : marco dot hugentobler at sourcepole dot ch
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   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 QGSSVGCACHE_H
#define QGSSVGCACHE_H

#include <QColor>
#include "qgis.h"
#include <QMap>
#include <QMultiHash>
#include <QMutex>
#include <QString>
#include <QUrl>
#include <QObject>
#include <QSizeF>
#include <QDateTime>
#include <QElapsedTimer>
#include <QPicture>
#include <QImage>
#include <QCache>
#include <QSet>

#include "qgis_core.h"

class QDomElement;

#ifndef SIP_RUN


class CORE_EXPORT QgsSvgCacheEntry
{
  public:

    QgsSvgCacheEntry() = delete;

    QgsSvgCacheEntry( const QString &path, double size, double strokeWidth, double widthScaleFactor, const QColor &fill, const QColor &stroke,
                      double fixedAspectRatio = 0 ) ;

    QgsSvgCacheEntry( const QgsSvgCacheEntry &rh ) = delete;
    QgsSvgCacheEntry &operator=( const QgsSvgCacheEntry &rh ) = delete;

    QString path;

    QDateTime fileModified;
    QElapsedTimer fileModifiedLastCheckTimer;
    int mFileModifiedCheckTimeout = 30000;

    double size = 0.0; //size in pixels (cast to int for QImage)
    double strokeWidth = 0;
    double widthScaleFactor = 1.0;

    double fixedAspectRatio = 0;

    QSizeF viewboxSize;

    QColor fill = Qt::black;
    QColor stroke = Qt::black;
    std::unique_ptr< QImage > image;
    std::unique_ptr< QPicture > picture;
    //content (with params replaced)
    QByteArray svgContent;

    //keep entries on a least, sorted by last access
    QgsSvgCacheEntry *nextEntry = nullptr;
    QgsSvgCacheEntry *previousEntry = nullptr;

    bool operator==( const QgsSvgCacheEntry &other ) const;
    int dataSize() const;

  private:
#ifdef SIP_RUN
    QgsSvgCacheEntry( const QgsSvgCacheEntry &rh );
#endif

};

#endif

class CORE_EXPORT QgsSvgCache : public QObject
{
    Q_OBJECT

  public:

    QgsSvgCache( QObject *parent SIP_TRANSFERTHIS = nullptr );

    ~QgsSvgCache() override;

    QImage svgAsImage( const QString &path, double size, const QColor &fill, const QColor &stroke, double strokeWidth,
                       double widthScaleFactor, bool &fitsInCache, double fixedAspectRatio = 0 );

    QPicture svgAsPicture( const QString &path, double size, const QColor &fill, const QColor &stroke, double strokeWidth,
                           double widthScaleFactor, bool forceVectorOutput = false, double fixedAspectRatio = 0 );

    QSizeF svgViewboxSize( const QString &path, double size, const QColor &fill, const QColor &stroke, double strokeWidth,
                           double widthScaleFactor, double fixedAspectRatio = 0 );

    void containsParams( const QString &path, bool &hasFillParam, QColor &defaultFillColor, bool &hasStrokeParam, QColor &defaultStrokeColor, bool &hasStrokeWidthParam,
                         double &defaultStrokeWidth ) const;

    void containsParams( const QString &path, bool &hasFillParam, bool &hasDefaultFillParam, QColor &defaultFillColor,
                         bool &hasFillOpacityParam, bool &hasDefaultFillOpacity, double &defaultFillOpacity,
                         bool &hasStrokeParam, bool &hasDefaultStrokeColor, QColor &defaultStrokeColor,
                         bool &hasStrokeWidthParam, bool &hasDefaultStrokeWidth, double &defaultStrokeWidth,
                         bool &hasStrokeOpacityParam, bool &hasDefaultStrokeOpacity, double &defaultStrokeOpacity ) const SIP_PYNAME( containsParamsV3 );

    QByteArray getImageData( const QString &path ) const;

    QByteArray svgContent( const QString &path, double size, const QColor &fill, const QColor &stroke, double strokeWidth,
                           double widthScaleFactor, double fixedAspectRatio = 0 );

  signals:
    void statusChanged( const QString  &statusQString );

    void remoteSvgFetched( const QString &url );

  private slots:
    void downloadProgress( qint64, qint64 );

    void onRemoteSvgFetched( const QString &url, bool success );

  private:

    QgsSvgCacheEntry *insertSvg( const QString &path, double size, const QColor &fill, const QColor &stroke, double strokeWidth,
                                 double widthScaleFactor, double fixedAspectRatio = 0 );

    void replaceParamsAndCacheSvg( QgsSvgCacheEntry *entry );
    void cacheImage( QgsSvgCacheEntry *entry );
    void cachePicture( QgsSvgCacheEntry *entry, bool forceVectorOutput = false );
    QgsSvgCacheEntry *cacheEntry( const QString &path, double size, const QColor &fill, const QColor &stroke, double strokeWidth,
                                  double widthScaleFactor, double fixedAspectRatio = 0 );

    void trimToMaximumSize();

    //Removes entry from the ordered list (but does not delete the entry itself)
    void takeEntryFromList( QgsSvgCacheEntry *entry );

    int mFileModifiedCheckTimeout = 30000;

    QMultiHash< QString, QgsSvgCacheEntry * > mEntryLookup;
    long mTotalSize = 0;

    //The svg cache keeps the entries on a double connected list, moving the current entry to the front.
    //That way, removing entries for more space can start with the least used objects.
    QgsSvgCacheEntry *mLeastRecentEntry = nullptr;
    QgsSvgCacheEntry *mMostRecentEntry = nullptr;

    static const long MAXIMUM_SIZE = 20000000;

    void replaceElemParams( QDomElement &elem, const QColor &fill, const QColor &stroke, double strokeWidth );

    void containsElemParams( const QDomElement &elem,
                             bool &hasFillParam, bool &hasDefaultFill, QColor &defaultFill,
                             bool &hasFillOpacityParam, bool &hasDefaultFillOpacity, double &defaultFillOpacity,
                             bool &hasStrokeParam, bool &hasDefaultStroke, QColor &defaultStroke,
                             bool &hasStrokeWidthParam, bool &hasDefaultStrokeWidth, double &defaultStrokeWidth,
                             bool &hasStrokeOpacityParam, bool &hasDefaultStrokeOpacity, double &defaultStrokeOpacity ) const SIP_PYNAME( containsParamsV3 );

    double calcSizeScaleFactor( QgsSvgCacheEntry *entry, const QDomElement &docElem, QSizeF &viewboxSize ) const;

    void removeCacheEntry( const QString &s, QgsSvgCacheEntry *entry );

    void printEntryList();

    QSize sizeForImage( const QgsSvgCacheEntry &entry, QSizeF &viewBoxSize, QSizeF &scaledSize ) const;

    QImage imageFromCachedPicture( const QgsSvgCacheEntry &entry ) const;

    QByteArray fetchImageData( const QString &path, bool &ok ) const;

    QByteArray mMissingSvg;

    QByteArray mFetchingSvg;

    mutable QMutex mMutex;

    mutable QCache< QString, QByteArray > mRemoteContentCache;
    mutable QSet< QString > mPendingRemoteUrls;

    friend class TestQgsSvgCache;
};

#endif // QGSSVGCACHE_H