Implemented a primitive decorator, allowing groups of primitives to be easily resized.

git-svn-id: svn+ssh://svn.tuxfamily.org/svnroot/qet/qet/trunk@2027 bfdf4180-ca20-0410-9c96-a3a8aa849046

sources/editor/elementprimitivedecorator.h

@@ -0,0 +1,90 @@
+#ifndef ELEMENTPRIMITIVEDECORATOR_H
+#define ELEMENTPRIMITIVEDECORATOR_H
+#include <QGraphicsObject>
+class ElementEditionCommand;
+class ElementScene;
+class CustomElementPart;
+
+/**
+	This class represents a decorator rendered above selected items so users
+	can manipulate (move, resize, ...) them.
+	
+	The implementation considers four kinds of bounding rects:
+	  - the actual, effective bounding rect as returned by the boundingRect() method
+	  - the original bounding rect, i.e. the rect containing all selected items at
+	      the beginning of operations (or after a command object was generated)
+	  - the new bounding rect, after the user moved or resized items
+	  - the former bounding rect, due to implementation details
+*/
+class ElementPrimitiveDecorator : public QGraphicsObject {
+	Q_OBJECT
+	
+	public:
+	ElementPrimitiveDecorator(QGraphicsItem * = 0);
+	virtual ~ElementPrimitiveDecorator();
+	
+	enum { Type = UserType + 2200 };
+	
+	// methods
+	QRectF internalBoundingRect() const;
+	virtual QRectF boundingRect () const;
+	virtual void paint(QPainter *, const QStyleOptionGraphicsItem *, QWidget * = 0);
+	virtual int type() const { return Type; }
+	void setItems(const QList<QGraphicsItem *> &);
+	void setItems(const QList<CustomElementPart *> &);
+	QList<CustomElementPart *> items() const;
+	QList<QGraphicsItem *> graphicsItems() const;
+	
+	public slots:
+	void adjust();
+	
+	signals:
+	void actionFinished(ElementEditionCommand *);
+	
+	protected:
+	void hoverMoveEvent(QGraphicsSceneHoverEvent *);
+	void mousePressEvent(QGraphicsSceneMouseEvent *);
+	void mouseDoubleClickEvent(QGraphicsSceneMouseEvent *);
+	void mouseMoveEvent(QGraphicsSceneMouseEvent *);
+	void mouseReleaseEvent(QGraphicsSceneMouseEvent *);
+	QPointF snapConstPointToGrid(const QPointF &) const;
+	void snapPointToGrid(QPointF &) const;
+	bool mustSnapToGrid(QGraphicsSceneMouseEvent *);
+	
+	private:
+	void init();
+	void saveOriginalBoundingRect();
+	void adjustEffectiveBoundingRect();
+	void startMovement();
+	void applyMovementToRect(int, const QPointF &, QRectF &);
+	CustomElementPart *singleItem() const;
+	void translateItems(const QPointF &);
+	void scaleItems(const QRectF &, const QRectF &);
+	QRectF getSceneBoundingRect(QGraphicsItem *) const;
+	void drawSquares(QPainter *, const QStyleOptionGraphicsItem *, QWidget *);
+	void drawResizeSquare(QPainter *, const QStyleOptionGraphicsItem *, QWidget *, const QRectF &);
+	void drawGenericSquare(QPainter *, const QStyleOptionGraphicsItem *, QWidget *, const QRectF &, const QColor &, const QColor &);
+	QList<QRectF> getResizingSquares();
+	QRectF getGenericSquare(const QPointF &);
+	int resizingSquareAtPos(const QPointF &);
+	
+	// attributes
+	private:
+	QList<CustomElementPart *> decorated_items_;
+	QRectF effective_bounding_rect_; ///< actual, effective bounding rect -- never shrinks
+	QRectF original_bounding_rect_; ///< original bounding rect
+	QRectF modified_bounding_rect_; ///< new bounding rect, after the user moved or resized items
+	
+	/**
+		Index of the square leading the current operation (resizing, etc.) or -1 if no
+		operation is occurring, -2 for a move operation.
+	*/
+	int current_operation_square_;
+	int grid_step_x_;              ///< Grid horizontal step
+	int grid_step_y_;              ///< Grid horizontal step
+	QPointF first_pos_;            ///< First point involved within the current resizing operation
+	QPointF latest_pos_;           ///< Latest point involved within the current resizing operation
+	QPointF mouse_offset_;         ///< Offset between the mouse position and the point to be snapped to grid when moving selection
+};
+
+#endif