summaryrefslogtreecommitdiffstats
path: root/library/focus.tcl
blob: bf0476d0a075d4095df8d987efd85a93b7561b26 (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
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
# focus.tcl --
#
# This file defines several procedures for managing the input
# focus.
#
# SCCS: @(#) focus.tcl 1.17 96/02/16 10:48:21
#
# Copyright (c) 1994-1995 Sun Microsystems, Inc.
#
# See the file "license.terms" for information on usage and redistribution
# of this file, and for a DISCLAIMER OF ALL WARRANTIES.
#

# tk_focusNext --
# This procedure returns the name of the next window after "w" in
# "focus order" (the window that should receive the focus next if
# Tab is typed in w).  "Next" is defined by a pre-order search
# of a top-level and its non-top-level descendants, with the stacking
# order determining the order of siblings.  The "-takefocus" options
# on windows determine whether or not they should be skipped.
#
# Arguments:
# w -		Name of a window.

proc tk_focusNext w {
    set cur $w
    while 1 {

	# Descend to just before the first child of the current widget.

	set parent $cur
	set children [winfo children $cur]
	set i -1

	# Look for the next sibling that isn't a top-level.

	while 1 {
	    incr i
	    if {$i < [llength $children]} {
		set cur [lindex $children $i]
		if {[winfo toplevel $cur] == $cur} {
		    continue
		} else {
		    break
		}
	    }

	    # No more siblings, so go to the current widget's parent.
	    # If it's a top-level, break out of the loop, otherwise
	    # look for its next sibling.

	    set cur $parent
	    if {[winfo toplevel $cur] == $cur} {
		break
	    }
	    set parent [winfo parent $parent]
	    set children [winfo children $parent]
	    set i [lsearch -exact $children $cur]
	}
	if {($cur == $w) || [tkFocusOK $cur]} {
	    return $cur
	}
    }
}

# tk_focusPrev --
# This procedure returns the name of the previous window before "w" in
# "focus order" (the window that should receive the focus next if
# Shift-Tab is typed in w).  "Next" is defined by a pre-order search
# of a top-level and its non-top-level descendants, with the stacking
# order determining the order of siblings.  The "-takefocus" options
# on windows determine whether or not they should be skipped.
#
# Arguments:
# w -		Name of a window.

proc tk_focusPrev w {
    set cur $w
    while 1 {

	# Collect information about the current window's position
	# among its siblings.  Also, if the window is a top-level,
	# then reposition to just after the last child of the window.
    
	if {[winfo toplevel $cur] == $cur}  {
	    set parent $cur
	    set children [winfo children $cur]
	    set i [llength $children]
	} else {
	    set parent [winfo parent $cur]
	    set children [winfo children $parent]
	    set i [lsearch -exact $children $cur]
	}

	# Go to the previous sibling, then descend to its last descendant
	# (highest in stacking order.  While doing this, ignore top-levels
	# and their descendants.  When we run out of descendants, go up
	# one level to the parent.

	while {$i > 0} {
	    incr i -1
	    set cur [lindex $children $i]
	    if {[winfo toplevel $cur] == $cur} {
		continue
	    }
	    set parent $cur
	    set children [winfo children $parent]
	    set i [llength $children]
	}
	set cur $parent
	if {($cur == $w) || [tkFocusOK $cur]} {
	    return $cur
	}
    }
}

# tkFocusOK --
#
# This procedure is invoked to decide whether or not to focus on
# a given window.  It returns 1 if it's OK to focus on the window,
# 0 if it's not OK.  The code first checks whether the window is
# viewable.  If not, then it never focuses on the window.  Then it
# checks the -takefocus option for the window and uses it if it's
# set.  If there's no -takefocus option, the procedure checks to
# see if (a) the widget isn't disabled, and (b) it has some key
# bindings.  If all of these are true, then 1 is returned.
#
# Arguments:
# w -		Name of a window.

proc tkFocusOK w {
    set code [catch {$w cget -takefocus} value]
    if {($code == 0) && ($value != "")} {
	if {$value == 0} {
	    return 0
	} elseif {$value == 1} {
	    return [winfo viewable $w]
	} else {
	    set value [uplevel #0 $value $w]
	    if {$value != ""} {
		return $value
	    }
	}
    }
    if {![winfo viewable $w]} {
	return 0
    }
    set code [catch {$w cget -state} value]
    if {($code == 0) && ($value == "disabled")} {
	return 0
    }
    regexp Key|Focus "[bind $w] [bind [winfo class $w]]"
}

# tk_focusFollowsMouse --
#
# If this procedure is invoked, Tk will enter "focus-follows-mouse"
# mode, where the focus is always on whatever window contains the
# mouse.  If this procedure isn't invoked, then the user typically
# has to click on a window to give it the focus.
#
# Arguments:
# None.

proc tk_focusFollowsMouse {} {
    set old [bind all <Enter>]
    set script {
	if {("%d" == "NotifyAncestor") || ("%d" == "NotifyNonlinear")
		|| ("%d" == "NotifyInferior")} {
	    if [tkFocusOK %W] {
		focus %W
	    }
	}
    }
    if {$old != ""} {
	bind all <Enter> "$old; $script"
    } else {
	bind all <Enter> $script
    }
}