1 /*=========================================================================
2 
3   Program:   Visualization Toolkit
4   Module:    vtkDistanceWidget.h,v
5 
6   Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
7   All rights reserved.
8   See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
9 
10      This software is distributed WITHOUT ANY WARRANTY; without even
11      the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
12      PURPOSE.  See the above copyright notice for more information.
13 
14 =========================================================================*/
15 /**
16  * @class   vtkDistanceWidget
17  * @brief   measure the distance between two points
18  *
19  * The vtkDistanceWidget is used to measure the distance between two points.
20  * The two end points can be positioned independently, and when they are
21  * released, a special PlacePointEvent is invoked so that special operations
22  * may be take to reposition the point (snap to grid, etc.) The widget has
23  * two different modes of interaction: when initially defined (i.e., placing
24  * the two points) and then a manipulate mode (adjusting the position of
25  * the two points).
26  *
27  * To use this widget, specify an instance of vtkDistanceWidget and a
28  * representation (a subclass of vtkDistanceRepresentation). The widget is
29  * implemented using two instances of vtkHandleWidget which are used to
30  * position the end points of the line. The representations for these two
31  * handle widgets are provided by the vtkDistanceRepresentation.
32  *
33  * @par Event Bindings:
34  * By default, the widget responds to the following VTK events (i.e., it
35  * watches the vtkRenderWindowInteractor for these events):
36  * <pre>
37  *   LeftButtonPressEvent - add a point or select a handle
38  *   MouseMoveEvent - position the second point or move a handle
39  *   LeftButtonReleaseEvent - release the handle
40  * </pre>
41  *
42  * @par Event Bindings:
43  * Note that the event bindings described above can be changed using this
44  * class's vtkWidgetEventTranslator. This class translates VTK events
45  * into the vtkDistanceWidget's widget events:
46  * <pre>
47  *   vtkWidgetEvent::AddPoint -- add one point; depending on the state
48  *                               it may the first or second point added. Or,
49  *                               if near a handle, select the handle.
50  *   vtkWidgetEvent::Move -- move the second point or handle depending on the state.
51  *   vtkWidgetEvent::EndSelect -- the handle manipulation process has completed.
52  * </pre>
53  *
54  * @par Event Bindings:
55  * This widget invokes the following VTK events on itself (which observers
56  * can listen for):
57  * <pre>
58  *   vtkCommand::StartInteractionEvent (beginning to interact)
59  *   vtkCommand::EndInteractionEvent (completing interaction)
60  *   vtkCommand::InteractionEvent (moving after selecting something)
61  *   vtkCommand::PlacePointEvent (after point is positioned;
62  *                                call data includes handle id (0,1))
63  * </pre>
64  *
65  * @sa
66  * vtkHandleWidget
67  */
68 
69 #ifndef vtkDistanceWidget_h
70 #define vtkDistanceWidget_h
71 
72 #include "vtkAbstractWidget.h"
73 #include "vtkInteractionWidgetsModule.h" // For export macro
74 
75 class vtkDistanceRepresentation;
76 class vtkHandleWidget;
77 class vtkDistanceWidgetCallback;
78 
79 class VTKINTERACTIONWIDGETS_EXPORT vtkDistanceWidget : public vtkAbstractWidget
80 {
81 public:
82   /**
83    * Instantiate this class.
84    */
85   static vtkDistanceWidget* New();
86 
87   ///@{
88   /**
89    * Standard methods for a VTK class.
90    */
91   vtkTypeMacro(vtkDistanceWidget, vtkAbstractWidget);
92   void PrintSelf(ostream& os, vtkIndent indent) override;
93   ///@}
94 
95   /**
96    * The method for activating and deactivating this widget. This method
97    * must be overridden because it is a composite widget and does more than
98    * its superclasses' vtkAbstractWidget::SetEnabled() method.
99    */
100   void SetEnabled(int) override;
101 
102   /**
103    * Specify an instance of vtkWidgetRepresentation used to represent this
104    * widget in the scene. Note that the representation is a subclass of vtkProp
105    * so it can be added to the renderer independent of the widget.
106    */
SetRepresentation(vtkDistanceRepresentation * r)107   void SetRepresentation(vtkDistanceRepresentation* r)
108   {
109     this->Superclass::SetWidgetRepresentation(reinterpret_cast<vtkWidgetRepresentation*>(r));
110   }
111 
112   /**
113    * Return the representation as a vtkDistanceRepresentation.
114    */
GetDistanceRepresentation()115   vtkDistanceRepresentation* GetDistanceRepresentation()
116   {
117     return reinterpret_cast<vtkDistanceRepresentation*>(this->WidgetRep);
118   }
119 
120   /**
121    * Create the default widget representation if one is not set.
122    */
123   void CreateDefaultRepresentation() override;
124 
125   /**
126    * Methods to change the whether the widget responds to interaction.
127    * Overridden to pass the state to component widgets.
128    */
129   void SetProcessEvents(vtkTypeBool) override;
130 
131   /**
132    * Description:
133    * Enum defining the state of the widget. By default the widget is in Start mode,
134    * and expects to be interactively placed. While placing the points the widget
135    * transitions to Define state. Once placed, the widget enters the Manipulate state.
136    */
137 
138   enum
139   {
140     Start = 0,
141     Define,
142     Manipulate
143   };
144 
145   ///@{
146   /**
147    * Set the state of the widget. If the state is set to "Manipulate" then it
148    * is assumed that the widget and its representation will be initialized
149    * programmatically and is not interactively placed. Initially the widget
150    * state is set to "Start" which means nothing will appear and the user
151    * must interactively place the widget with repeated mouse selections. Set
152    * the state to "Start" if you want interactive placement. Generally state
153    * changes must be followed by a Render() for things to visually take
154    * effect.
155    */
156   virtual void SetWidgetStateToStart();
157   virtual void SetWidgetStateToManipulate();
158   ///@}
159 
160   /**
161    * Return the current widget state.
162    */
GetWidgetState()163   virtual int GetWidgetState() { return this->WidgetState; }
164 
165 protected:
166   vtkDistanceWidget();
167   ~vtkDistanceWidget() override;
168 
169   // The state of the widget
170   int WidgetState;
171   int CurrentHandle;
172 
173   // Callback interface to capture events when
174   // placing the widget.
175   static void AddPointAction(vtkAbstractWidget*);
176   static void MoveAction(vtkAbstractWidget*);
177   static void EndSelectAction(vtkAbstractWidget*);
178   static void AddPointAction3D(vtkAbstractWidget*);
179   static void MoveAction3D(vtkAbstractWidget*);
180   static void EndSelectAction3D(vtkAbstractWidget*);
181 
182   // The positioning handle widgets
183   vtkHandleWidget* Point1Widget;
184   vtkHandleWidget* Point2Widget;
185   vtkDistanceWidgetCallback* DistanceWidgetCallback1;
186   vtkDistanceWidgetCallback* DistanceWidgetCallback2;
187 
188   // Methods invoked when the handles at the
189   // end points of the widget are manipulated
190   void StartDistanceInteraction(int handleNum);
191   void DistanceInteraction(int handleNum);
192   void EndDistanceInteraction(int handleNum);
193 
194   friend class vtkDistanceWidgetCallback;
195 
196 private:
197   vtkDistanceWidget(const vtkDistanceWidget&) = delete;
198   void operator=(const vtkDistanceWidget&) = delete;
199 };
200 
201 #endif
202