qgscomposermousehandles.h

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/***************************************************************************
                         qgscomposermousehandles.h
                             -------------------
    begin                : September 2013
    copyright            : (C) 2013 by Nyall Dawson, Radim Blazek
    email                : nyall.dawson@gmail.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 QGSCOMPOSERMOUSEHANDLES_H
#define QGSCOMPOSERMOUSEHANDLES_H

#include <QGraphicsRectItem>
#include <QObject>

class QgsComposition;
class QgsComposerItem;
class QGraphicsView;

class CORE_EXPORT QgsComposerMouseHandles: public QObject, public QGraphicsRectItem
{
    Q_OBJECT
  public:

    enum MouseAction
    {
      MoveItem,
      ResizeUp,
      ResizeDown,
      ResizeLeft,
      ResizeRight,
      ResizeLeftUp,
      ResizeRightUp,
      ResizeLeftDown,
      ResizeRightDown,
      SelectItem,
      NoAction
    };

    enum ItemPositionMode
    {
      UpperLeft,
      UpperMiddle,
      UpperRight,
      MiddleLeft,
      Middle,
      MiddleRight,
      LowerLeft,
      LowerMiddle,
      LowerRight
    };

    enum SnapGuideMode
    {
      Item,
      Point
    };

    QgsComposerMouseHandles( QgsComposition *composition );
    virtual ~QgsComposerMouseHandles();

    void setComposition( QgsComposition* c ) { mComposition = c; }
    QgsComposition* composition() { return mComposition; }

    void paint( QPainter* painter, const QStyleOptionGraphicsItem* itemStyle, QWidget* pWidget ) override;

    QgsComposerMouseHandles::MouseAction mouseActionForScenePos( const QPointF& sceneCoordPos );

    bool isDragging() { return mIsDragging; }

    bool isResizing() { return mIsResizing; }

  protected:

    void mouseMoveEvent( QGraphicsSceneMouseEvent* event ) override;
    void mouseReleaseEvent( QGraphicsSceneMouseEvent* event ) override;
    void mousePressEvent( QGraphicsSceneMouseEvent* event ) override;
    void mouseDoubleClickEvent( QGraphicsSceneMouseEvent* event ) override;
    void hoverMoveEvent( QGraphicsSceneHoverEvent * event ) override;
    void hoverLeaveEvent( QGraphicsSceneHoverEvent * event ) override;

  public slots:

    void selectionChanged();

    void selectedItemSizeChanged();

    void selectedItemRotationChanged();

  private:

    QgsComposition* mComposition; //reference to composition
    QGraphicsView* mGraphicsView; //reference to QGraphicsView

    QgsComposerMouseHandles::MouseAction mCurrentMouseMoveAction;
    QPointF mMouseMoveStartPos;
    QPointF mLastMouseEventPos;
    QPointF mBeginMouseEventPos;
    QPointF mBeginHandlePos;
    double mBeginHandleWidth;
    double mBeginHandleHeight;

    QRectF mResizeRect;
    double mResizeMoveX;
    double mResizeMoveY;

    bool mIsDragging;
    bool mIsResizing;

    QGraphicsLineItem* mHAlignSnapItem;
    QGraphicsLineItem* mVAlignSnapItem;

    QSizeF mCursorOffset;

    QRectF selectionBounds() const;

    bool selectionRotation( double & rotation ) const;

    void updateHandles();
    void drawHandles( QPainter* painter, double rectHandlerSize );
    void drawSelectedItemBounds( QPainter* painter );

    double rectHandlerBorderTolerance();

    Qt::CursorShape cursorForPosition( const QPointF& itemCoordPos );

    QgsComposerMouseHandles::MouseAction mouseActionForPosition( const QPointF& itemCoordPos );

    void dragMouseMove( const QPointF& currentPosition, bool lockMovement, bool preventSnap );

    QSizeF calcCursorEdgeOffset( const QPointF &cursorPos );

    void resizeMouseMove( const QPointF& currentPosition, bool lockAspect, bool fromCenter );

    QGraphicsLineItem* hAlignSnapItem();
    void deleteHAlignSnapItem();
    QGraphicsLineItem* vAlignSnapItem();
    void deleteVAlignSnapItem();
    void deleteAlignItems();

    QPointF snapPoint( const QPointF& originalPoint, QgsComposerMouseHandles::SnapGuideMode mode );
    QPointF alignItem( double& alignX, double& alignY, double unalignedX, double unalignedY );
    QPointF alignPos( const QPointF& pos, double& alignX, double& alignY );

    //helper functions for item align
    void collectAlignCoordinates( QMap< double, const QgsComposerItem* >& alignCoordsX, QMap< double, const QgsComposerItem* >& alignCoordsY );
    bool nearestItem( const QMap< double, const QgsComposerItem* >& coords, double value, double& nearestValue ) const;
    void checkNearestItem( double checkCoord, const QMap< double, const QgsComposerItem* >& alignCoords, double& smallestDiff, double itemCoordOffset, double& itemCoord, double& alignCoord );

    //tries to return the current QGraphicsView attached to the composition
    QGraphicsView* graphicsView();

    //sets the mouse cursor for the QGraphicsView attached to the composition (workaround qt bug #3732)
    void setViewportCursor( Qt::CursorShape cursor );

    //resets the composer window status bar to the default message
    void resetStatusBar();
};

#endif // QGSCOMPOSERMOUSEHANDLES_H