blob: cdea5bbdae867a0afabb6cacef3602dfd3966fa2 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Focus Handling</title>
<meta name="generator" content="DocBook XSL Stylesheets V1.71.0">
<link rel="start" href="index.html" title="libccc Reference Manual">
<link rel="up" href="ccc-Internals.html" title="Part II. Internals">
<link rel="prev" href="ccc-Event-Handling.html" title="Event Handling">
<link rel="next" href="ccc-Focus-Handling-The-focus-Signal.html" title="The focus signal">
<meta name="generator" content="GTK-Doc V1.8 (XML mode)">
<link rel="stylesheet" href="style.css" type="text/css">
<link rel="part" href="ccc-Working-with-the-Canvas.html" title="Part I. Working with the Canvas">
<link rel="chapter" href="ccc-Known-Bugs.html" title="Known Bugs">
<link rel="chapter" href="ccc-Writing-custom-canvas-items.html" title="Writing custom canvas items">
<link rel="part" href="ccc-Internals.html" title="Part II. Internals">
<link rel="chapter" href="ccc-Bounds-Handling.html" title="Bounds Handling">
<link rel="chapter" href="ccc-Event-Handling.html" title="Event Handling">
<link rel="chapter" href="ccc-Focus-Handling.html" title="Focus Handling">
<link rel="chapter" href="ccc-Zoom-and-Scroll.html" title="Zooming and Scrolling">
<link rel="chapter" href="ccc-Known-Bugs.html" title="Known Bugs">
<link rel="part" href="ccc-API-Reference.html" title="Part III. API Reference">
<link rel="chapter" href="ccc-Object-Hierarchy.html" title="Object Hierarchy">
<link rel="chapter" href="ccc-Fundamentals.html" title="Fundamentals">
<link rel="chapter" href="ccc-Canvas-Items.html" title="Canvas Items">
<link rel="chapter" href="ccc-View-Elements.html" title="View Elements">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
<table class="navigation" id="top" width="100%" summary="Navigation header" cellpadding="2" cellspacing="2"><tr valign="middle">
<td><a accesskey="p" href="ccc-Event-Handling.html"><img src="left.png" width="24" height="24" border="0" alt="Prev"></a></td>
<td><a accesskey="u" href="ccc-Internals.html"><img src="up.png" width="24" height="24" border="0" alt="Up"></a></td>
<td><a accesskey="h" href="index.html"><img src="home.png" width="24" height="24" border="0" alt="Home"></a></td>
<th width="100%" align="center">libccc Reference Manual</th>
<td><a accesskey="n" href="ccc-Focus-Handling-The-focus-Signal.html"><img src="right.png" width="24" height="24" border="0" alt="Next"></a></td>
</tr></table>
<div class="chapter" lang="en">
<div class="titlepage"><div><div><h2 class="title">
<a name="ccc-Focus-Handling"></a>Focus Handling</h2></div></div></div>
<div class="toc"><dl>
<dt><span class="sect1"><a href="ccc-Focus-Handling.html#ccc-Focus-Handling-Introduction">Introduction</a></span></dt>
<dt><span class="sect1"><a href="ccc-Focus-Handling-The-focus-Signal.html">The focus signal</a></span></dt>
<dd><dl>
<dt><span class="sect2"><a href="ccc-Focus-Handling-The-focus-Signal.html#ccc-Focus-handling-The-Beginning">The Beginning</a></span></dt>
<dt><span class="sect2"><a href="ccc-Focus-Handling-The-focus-Signal.html#ccc-Focus-Handling-The-Sequel">The Sequel</a></span></dt>
<dt><span class="sect2"><a href="ccc-Focus-Handling-The-focus-Signal.html#ccc-Focus-Handling-The-Final">The Final</a></span></dt>
</dl></dd>
</dl></div>
<p>
This chapter describes the implementation of focus handling in the canvas,
which is used for the criawips presentation application.
</p>
<div class="sect1" lang="en">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="ccc-Focus-Handling-Introduction"></a>Introduction</h2></div></div></div>
<p>
The focus is a meta-information, which is correctly called 'the focused
item'. The focused item is the one which receives keyboard events. The
focus can be moved by using the keys up, down, left, right, tab and
shift-tab (usually also available with ctrl if the keys are used for
other things - like text editing).
</p>
<p>
The focus is view-dependent, there may even be views (like the tree or
pixbuf renderers) which don't have a focus at all. This make the focus
implementation slightly harder than GnomeCanvas' focus handling has been.
</p>
<p>
The focus list (which is the list starting with the focused item and then
mentioning all its parents up to the root of the view - which might not
always be the root of the model) is very important as we need to know
which items already were focused and which were not. As we cannot store
the focused elements in the model - which was possible with the
GnomeCanvas - we need to store it in the view. So the view needs to take
care about the focus list.
</p>
</div>
</div>
</body>
</html>
|
