qgsannotationregistry.h

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/***************************************************************************
    qgsannotationregistry.h
    -----------------------
    Date                 : January 2017
    Copyright            : (C) 2017 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 QGSANNOTATIONREGISTRY_H
#define QGSANNOTATIONREGISTRY_H
 
#define SIP_NO_FILE
 
#include <functional>
 
#include "qgis_core.h"
#include "qgsannotation.h"
#include "qgshtmlannotation.h"
#include "qgssvgannotation.h"
#include "qgstextannotation.h"
 
#include <QString>
 
using namespace Qt::StringLiterals;

 
// None of this is stable API!

typedef std::function < QgsAnnotation*() > QgsCreateAnnotationFunc;

class CORE_EXPORT QgsAnnotationMetadata
{
  public:

    QgsAnnotationMetadata( const QString &typeName, const QgsCreateAnnotationFunc &createFunc )
      : mTypeName( typeName )
      , mCreateFunc( createFunc )
    {}

    QString type() const { return mTypeName; }

    QgsAnnotation *createAnnotation() const { return mCreateFunc ? mCreateFunc() : nullptr ; }
 
  private:
 
    QString mTypeName;
    QgsCreateAnnotationFunc mCreateFunc = nullptr;
 
    QgsAnnotationMetadata() = default;
    friend class QMap< QString, QgsAnnotationMetadata >;
 
};

class CORE_EXPORT QgsAnnotationRegistry
{
 
  public:

    QgsAnnotationRegistry()
    {
      addAnnotationType( QgsAnnotationMetadata( u"TextAnnotationItem"_s, QgsTextAnnotation::create ) );
      addAnnotationType( QgsAnnotationMetadata( u"HtmlAnnotationItem"_s, QgsHtmlAnnotation::create ) );
      addAnnotationType( QgsAnnotationMetadata( u"SVGAnnotationItem"_s, QgsSvgAnnotation::create ) );
    }

    bool addAnnotationType( const QgsAnnotationMetadata &metadata )
    {
      if ( mMetadata.contains( metadata.type() ) )
        return false;
 
      mMetadata.insert( metadata.type(), metadata );
      return true;
    }

    QgsAnnotation *create( const QString &typeName ) const
    {
      if ( !mMetadata.contains( typeName ) )
        return nullptr;
 
      return mMetadata.value( typeName ).createAnnotation();
    }
 
  private:
 
    QMap< QString, QgsAnnotationMetadata > mMetadata;
 
};

 
#endif // QGSANNOTATIONREGISTRY_H