anchovy.gui.eventpropagators source code

1 /*
2 Copyright (c) 2013 Andrey Penechko
3 
4 Boost Software License - Version 1.0 - August 17th, 2003
5 
6 Permission is hereby granted, free of charge, to any person or organization
7 obtaining a copy of the software and accompanying documentation covered by
8 this license the "Software" to use, reproduce, display, distribute,
9 execute, and transmit the Software, and to prepare derivative works of the
10 Software, and to permit third-parties to whom the Software is furnished to
11 do so, all subject to the following:
12 
13 The copyright notices in the Software and this entire statement, including
14 the above license grant, this restriction and the following disclaimer,
15 must be included in all copies of the Software, in whole or in part, and
16 all derivative works of the Software, unless such copies or derivative
17 works are solely in the form of machine-executable object code generated by
18 a source language processor.
19 
20 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
23 SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
24 FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
25 ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
26 DEALINGS IN THE SOFTWARE.
27 */
28 
29 module anchovy.gui.eventpropagators;
30 
31 import std.traits;
32 import anchovy.gui;
33 
34 /// 
35 enum PropagatingStrategy
36 {
37 	/// First visits parent then child until target is reached.
38 	/// Then sets event's bubbling flag to true and visits widgets from
39 	/// target to root.
40 	SinkBubble,
41 
42 	/// First visits target then its parent etc, until reaches root.
43 	/// Then sets event's sinking flag to true and visits widgets from root to target.
44 	BubbleSink,
45 
46 	/// Visit all the subtree from bottom up. parent gets visited after all its children was visited.
47 	/// Also called Pre-order.
48 	ChildrenFirst,
49 
50 	/// Visits all subtree from root to leafs, visiting parent first and then all its subtrees. Depth-first.
51 	/// Also called Post-order.
52 	ParentFirst
53 }
54 
55 enum OnHandle
56 {
57 	StopTraversing,
58 	ContinueTraversing
59 }
60 
61 Widget[] propagateEventSinkBubble(OnHandle onHandle = OnHandle.StopTraversing)(Widget[] widgets, Event event)
62 {
63 	// Phase 1: event sinking to target.
64 	event.sinking = true;
65 
66 	foreach(index, widget; widgets)
67 	{
68 		event.handled = event.handled || widget.handleEvent(event);
69 
70 		static if(onHandle == OnHandle.StopTraversing)
71 		{
72 			if (event.handled) return widgets[0..index+1];
73 		}
74 	}
75 
76 	// Phase 2: event bubling from target.
77 	event.bubbling = true;
78 	foreach_reverse(index, widget; widgets)
79 	{
80 		event.handled = event.handled || widget.handleEvent(event);
81 		
82 		static if(onHandle == OnHandle.StopTraversing)
83 		{
84 			if (event.handled) return widgets[0..index+1];
85 		}
86 	}
87 
88 	return [];
89 }
90 
91 void propagateEventParentFirst(Widget root, Event event)
92 {
93 	event.sinking = true;
94 
95 	void propagateEvent(Widget root)
96 	{
97 		root.handleEvent(event);
98 		
99 		foreach(child; root.getPropertyAs!("children", Widget[]))
100 		{
101 			propagateEvent(child);
102 		}
103 	}
104 
105 	propagateEvent(root);
106 }
107 
108 void propagateEventSinkBubbleTree(Widget root, Event e)
109 {
110 	e.sinking = true;
111 	root.handleEvent(e);
112 
113 	foreach (widget; root.getPropertyAs!("children", Widget[]))
114 	{
115 		e.sinking = true;
116 		widget.propagateEventSinkBubbleTree(e);
117 	}
118 	
119 	e.bubbling = true;
120 	root.handleEvent(e);
121 }
122 
123 void propagateEventChildrenFirst(Widget root, Event event)
124 {
125 	event.bubbling = true;
126 
127 	void propagateEvent(Widget root)
128 	{
129 		foreach(child; root.getPropertyAs!("children", Widget[]))
130 		{
131 			propagateEvent(child);
132 		}
133 
134 		root.handleEvent(event);
135 	}
136 
137 	propagateEvent(root);
138 }
139 
140 /// Tests all root's children with pred.
141 /// Then calls itself with found child.
142 /// Adds widgets satisfying pred to returned array.
143 /// Root widget is added first.
144 /// Can be used to find widget that is under cursor
145 /// Parameters:
146 ///   pred function like bool fun(Widget widget, ...)
147 ///   root root of widget subtree/tree
148 Widget[] buildPathToLeaf(alias pred, T...)(Widget root, T data)
149 {
150 	Widget[] path;
151 
152 	bool traverse(Widget root)
153 	{
154 		if(!pred(root, data)) return false;
155 		
156 		path ~= root;
157 
158 		foreach(child; root.getPropertyAs!("children", Widget[]))
159 		{
160 			if (traverse(child))
161 			{
162 				return true;
163 			}
164 		}
165 
166 		return true;
167 	}
168 
169 	traverse(root);
170 
171 	return path;
172 }