qgsexpressionpreviewwidget.h

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/***************************************************************************
    qgsexpressionpreviewwidget.h
     --------------------------------------
    Date                 : march 2020 - quarantine day 12
    Copyright            : (C) 2020 by Denis Rouzaud
    Email                : [email protected]
 ***************************************************************************
 *                                                                         *
 *   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 QGSEXPRESSIONPREVIEWWIDGET_H
#define QGSEXPRESSIONPREVIEWWIDGET_H
 
#include "ui_qgsexpressionpreviewbase.h"
 
#include <functional>
 
#include "qgis_gui.h"
#include "qgsdistancearea.h"
#include "qgsexpression.h"
#include "qgsexpressioncontext.h"
 
#include <QWidget>
 
class QAction;
class QgsVectorLayer;

class GUI_EXPORT QgsExpressionPreviewWidget : public QWidget, private Ui::QgsExpressionPreviewWidgetBase
{
    Q_OBJECT
  public:
    explicit QgsExpressionPreviewWidget( QWidget *parent = nullptr );

    void setLayer( QgsVectorLayer *layer );
 
#ifndef SIP_RUN

    void setCustomPreviewGenerator( const QString &label, const QList<QPair<QString, QVariant>> &choices, const std::function<QgsExpressionContext( const QVariant & )> &previewContextGenerator );
#else

    void setCustomPreviewGenerator( const QString &label, const QList<QPair<QString, QVariant>> &choices, SIP_PYCALLABLE );
    //%MethodCode
    Py_XINCREF( a2 );
    Py_BEGIN_ALLOW_THREADS sipCpp->setCustomPreviewGenerator( *a0, *a1, [a2]( const QVariant &value ) -> QgsExpressionContext {
      QgsExpressionContext res;
      SIP_BLOCK_THREADS
      PyObject *s = sipCallMethod( NULL, a2, "D", &value, sipType_QVariant, NULL );
      int state;
      int sipIsError = 0;
      QgsExpressionContext *t1 = reinterpret_cast<QgsExpressionContext *>( sipConvertToType( s, sipType_QgsExpressionContext, 0, SIP_NOT_NONE, &state, &sipIsError ) );
      if ( sipIsError == 0 )
      {
        res = QgsExpressionContext( *t1 );
      }
      sipReleaseType( t1, sipType_QgsExpressionContext, state );
      SIP_UNBLOCK_THREADS
      return res;
    } );
 
    Py_END_ALLOW_THREADS
    //%End
#endif

    void setExpressionText( const QString &expression );

    QgsExpressionContext expressionContext() const { return mExpressionContext; }

    void setExpressionContext( const QgsExpressionContext &context );

    void setGeomCalculator( const QgsDistanceArea &da );

    bool evalError() const;

    bool parserError() const;

    const QgsExpressionNode *rootNode() const { return mExpression.rootNode(); }

    QList<QgsExpression::ParserError> parserErrors() const { return mExpression.parserErrors(); }

    QString currentPreviewText() const;
 
  signals:

    void expressionParsed( bool isValid );

    void evalErrorChanged();

    void parserErrorChanged();

    void toolTipChanged( const QString &toolTip );
 
  public slots:
    void setCurrentFeature( const QgsFeature &feature );
 
 
  private slots:
    void linkActivated( const QString & );
    void setEvalError( bool evalError );
    void setParserError( bool parserError );
    void copyFullExpressionValue();
    void setCustomChoice( int );
 
  private:
    void setExpressionToolTip( const QString &toolTip );
    void refreshPreview();
 
    QgsVectorLayer *mLayer = nullptr;
    QgsExpressionContext mExpressionContext;
    QgsDistanceArea mDa;
    bool mUseGeomCalculator = false;
    QString mToolTip;
    bool mEvalError = true;
    bool mParserError = true;
    QString mExpressionText;
    QgsExpression mExpression;
    QAction *mCopyPreviewAction = nullptr;
 
    std::function<QgsExpressionContext( const QVariant & )> mCustomPreviewGeneratorFunction;
};
 
#endif // QGSEXPRESSIONPREVIEWWIDGET_H