1XmProcessTraversal(library call) XmProcessTraversal(library call)
2
6 XmProcessTraversal — A function that determines which component
7 receives keyboard events when a widget has the focus
8
10 #include <Xm/Xm.h>
11 Boolean XmProcessTraversal(
12 Widget widget,
13 XmTraversalDirection direction);
14
16 XmProcessTraversal determines which component of a hierarchy receives
17 keyboard events when the hierarchy that contains the given widget has
18 keyboard focus.
19 XmProcessTraversal changes focus only when the keyboard focus policy of
21 the widget hierarchy is explicit. If the XmNkeyboardFocusPolicy of the
22 nearest shell ancestor of the given widget is not XmEXPLICIT, XmPro‐
23 cessTraversal returns False without making any focus changes.
24 widget Specifies the widget ID of the widget whose hierarchy is to
26 be traversed
27 direction Specifies the direction of traversal
29 DEFINITIONS
31 In order to be eligible to receive keyboard focus when the shell's
32 XmNkeyboardFocusPolicy is XmEXPLICIT, a widget or gadget must meet the
33 following conditions:
34 · The widget and its ancestors are not in the process of being
36 destroyed.
37 · The widget and its ancestors are sensitive. A widget is sensi‐
39 tive when its XmNsensitive and XmNancestorSensitive resources are
40 both True.
41 · The XmNtraversalOn resource for the widget and its ancestors is
43 True.
44 · The widget is viewable. This means that the widget and its
46 ancestors are managed, realized, and (except for gadgets) mapped.
47 Furthermore, in general, some part of the widget's rectangular
48 area must be unobscured by the widget's ancestors. If an applica‐
49 tion unmaps a widget that has its XmNmappedWhenManaged resource
50 set to True, the result is undefined.
51 In a ScrolledWindow with an XmNscrollingPolicy of XmAUTO‐
53 MATIC, a widget that is obscured because it is not within the
54 clip window may be able to receive focus if some part of the
55 widget is within the work area and if an XmNtraverseObscured‐
56 Callback routine can make the widget at least partially visi‐
57 ble by scrolling the window.
58 In general only primitives, gadgets, and Drawing Area are eligible to
60 receive focus. Most managers cannot receive focus even if they meet
61 all these conditions.
62 The direction argument identifies the kind of traversal action to take.
64 The descriptions of these actions below refer to traversable non-tab-
65 group widgets and traversable tab groups.
66 · A traversable non-tab-group widget is a widget that is not a tab
68 group and that meets all the conditions for receiving focus
69 described above.
70 · A traversable tab group widget is a tab group widget that meets
72 the same conditions, except that a manager that is a tab group
73 and meets the other conditions is also eligible for traversal as
74 long as it contains a descendant that can receive focus.
75 A tab group is a widget whose XmNnavigationType is:
77 · XmTAB_GROUP or XmSTICKY_TAB_GROUP, if the hierarchy (up to the
79 nearest shell ancestor) that contains the widget has no widget
80 whose XmNnavigationType is XmEXCLUSIVE_TAB_GROUP
81 · XmEXCLUSIVE_TAB_GROUP or XmSTICKY_TAB_GROUP, if the hierarchy (up
83 to the nearest shell ancestor) that contains the widget has any
84 widget whose XmNnavigationType is XmEXCLUSIVE_TAB_GROUP
85 TRAVERSAL ACTIONS
87 The hierarchy to be traversed is that containing the widget argument.
88 This hierarchy is traversed only up to the nearest shell; XmPro‐
89 cessTraversal does not move focus from one shell to another. If the
90 shell containing widget does not currently have the focus, any change
91 that XmProcessTraversal makes to the element with focus within that
92 shell does not take effect until the next time the shell receives
93 focus.
94 XmProcessTraversal begins the traversal action from the widget in the
96 hierarchy that currently has keyboard focus or that last had focus when
97 the user traversed away from the shell hierarchy.
98 The value of the direction argument determines which of three kinds of
100 traversal action to take:
101 · Traversal to a non-tab-group widget. This kind of traversal is
103 possible only when the widget that currently has focus is not a
104 tab group; otherwise, XmProcessTraversal returns False for these
105 actions.
106 These actions do not move focus from one tab group to
108 another. The actions first determine the containing tab
109 group. This is the tab group containing the widget that cur‐
110 rently has focus. The actions traverse only to a non-tab-
111 group widget within the containing tab group.
112 A non-tab-group widget is eligible for this kind of traversal
114 if the widget is traversable and has no tab group ancestors
115 up to the containing tab group. If the tab group contains no
116 traversable non-tab-group widgets, XmProcessTraversal returns
117 False.
118 Following are the possible values of the direction argument.
120 Note that when actions wrap, wrapping occurs in the traversal
121 direction. The following describes what happens in a left to
122 right environment:
123 · XmTRAVERSE_RIGHT—If the XmNnavigationType of the con‐
125 taining tab group is not XmEXCLUSIVE_TAB_GROUP, focus
126 moves to the next traversable non-tab-group widget to
127 the right of the widget that currently has focus. In a
128 left to right environment, at the right side of the tab
129 group this action wraps to the non-tab-group widget at
130 the left side and next toward the bottom. At the
131 rightmost widget in the bottom row of the tab group
132 this action wraps to the non-tab-group widget at the
133 leftmost widget in the upper row.
134 In a right to left environment, at the right side
136 of the tab group, this action wraps to the non-tab-
137 group widget at the left side and next toward the
138 top. At the rightmost widget in the upper row of
139 the tab group this action wraps to the non-tab-
140 group widget at the leftmost widget in the bottom
141 row.
142 If the XmNnavigationType of the containing tab
144 group is XmEXCLUSIVE_TAB_GROUP, focus moves to the
145 next traversable non-tab-group widget in the tab
146 group, proceeding in the order in which the widgets
147 appear in their parents' XmNchildren lists. After
148 the last widget in the tab group, this action wraps
149 to the first non-tab-group widget.
150 · XmTRAVERSE_LEFT—If the XmNnavigationType of the con‐
152 taining tab group is not XmEXCLUSIVE_TAB_GROUP, focus
153 moves to the next traversable non-tab-group widget to
154 the left of the widget that currently has focus. In a
155 left to right environment, at the left side of the tab
156 group this action wraps to the non-tab-group widget at
157 the right side and next toward the top. At the left‐
158 most widget in the upper row of the tab group this
159 action wraps to the non-tab-group widget at the right‐
160 most widget in the bottom row.
161 In a right to left environment, at the left side of
163 the tab group this action wraps to the non-tab-
164 group widget at the right side and next toward the
165 bottom. At the leftmost widget in the bottom row of
166 the tab group this action wraps to the non-tab-
167 group widget at the rightmost widget in the upper
168 row.
169 If the XmNnavigationType of the containing tab
171 group is XmEXCLUSIVE_TAB_GROUP, focus moves to the
172 previous traversable non-tab-group widget in the
173 tab group, proceeding in the reverse order in which
174 the widgets appear in their parents' XmNchildren
175 lists. After the first widget in the tab group,
176 this action wraps to the last non-tab-group widget.
177 · XmTRAVERSE_DOWN—If the XmNnavigationType of the con‐
179 taining tab group is not XmEXCLUSIVE_TAB_GROUP, focus
180 moves to the next traversable non-tab-group widget
181 below the widget that currently has focus. In a left
182 to right environment, at the bottom of the tab group
183 this action wraps to the non-tab-group widget at the
184 top and next toward the right. At the bottom widget in
185 the rightmost column of the tab group this action wraps
186 to the non-tab-group widget at the top widget in the
187 leftmost column.
188 In a right to left environment, at the bottom of
190 the tab group this action wraps to the non-tab-
191 group widget at the top and next toward the left.
192 At the bottom widget of the leftmost widget of the
193 tab group this action wraps to the non-tab-group
194 widget at the top widget of the rightmost column.
195 If the XmNnavigationType of the containing tab
197 group is XmEXCLUSIVE_TAB_GROUP, focus moves to the
198 next traversable non-tab-group widget in the tab
199 group, proceeding in the order in which the widgets
200 appear in their parents' XmNchildren lists. After
201 the last widget in the tab group, this action wraps
202 to the first non-tab-group widget.
203 · XmTRAVERSE_UP—If the XmNnavigationType of the contain‐
205 ing tab group is not XmEXCLUSIVE_TAB_GROUP, focus moves
206 to the next traversable non-tab-group widget above the
207 widget that currently has focus. In a left to right
208 environment, at the top of the tab group this action
209 wraps to the non-tab-group widget at the bottom and
210 next toward the left. At the top widget of the left‐
211 most column of the tab group this action wraps to the
212 non-tab-group widget at the bottom widget of the right‐
213 most column.
214 In a right to left environment, at the top of the
216 tab group this action wraps to the non-tab-group
217 widget at the bottom and next toward the right. At
218 the top widget of the right most column of the tab
219 group this action wraps to the non-tab-group widget
220 at the bottom widget of the leftmost column.
221 If the XmNnavigationType of the containing tab
223 group is XmEXCLUSIVE_TAB_GROUP, focus moves to the
224 previous traversable non-tab-group widget in the
225 tab group, proceeding in the reverse order in which
226 the widgets appear in their parents' XmNchildren
227 lists. After the first widget in the tab group,
228 this action wraps to the last non-tab-group widget.
229 · XmTRAVERSE_NEXT—Focus moves to the next traversable
231 non-tab-group widget in the tab group, proceeding in
232 the order in which the widgets appear in their parents'
233 XmNchildren lists. After the last widget in the tab
234 group, this action wraps to the first non-tab-group
235 widget.
236 · XmTRAVERSE_PREV—Focus moves to the previous traversable
238 non-tab-group widget in the tab group, proceeding in
239 the reverse order in which the widgets appear in their
240 parents' XmNchildren lists. After the first widget in
241 the tab group, this action wraps to the last non-tab-
242 group widget.
243 · XmTRAVERSE_HOME—If the XmNnavigationType of the con‐
245 taining tab group is not XmEXCLUSIVE_TAB_GROUP, focus
246 moves to the first traversable non-tab-group widget at
247 the initial focus of the tab group.
248 If the XmNnavigationType of the containing tab
250 group is XmEXCLUSIVE_TAB_GROUP, focus moves to the
251 first traversable non-tab-group widget in the tab
252 group, according to the order in which the widgets
253 appear in their parents' XmNchildren lists.
254 · Traversal to a tab group. These actions first determine the cur‐
256 rent widget hierarchy and the containing tab group. The current
257 widget hierarchy is the widget hierarchy whose root is the near‐
258 est shell ancestor of the widget that currently has focus. The
259 containing tab group is is the tab group containing the widget
260 that currently has focus. If the current widget hierarchy con‐
261 tains no traversable tab groups, XmProcessTraversal returns
262 False.
263 Following are the possible values of the direction argument.
265 If any tab group in the current widget hierarchy has an XmN‐
266 navigationType of XmEXCLUSIVE_TAB_GROUP, traversal of tab
267 groups in the hierarchy proceeds to widgets in the order in
268 which their XmNnavigationType resources were specified as
269 XmEXCLUSIVE_TAB_GROUP or XmSTICKY_TAB_GROUP.:
270 · XmTRAVERSE_NEXT_TAB_GROUP—Finds the hierarchy that con‐
272 tains widget, finds the active tab group (if any), and
273 makes the next tab group the active tab group in the
274 hierarchy.
275 · XmTRAVERSE_PREV_TAB_GROUP—Finds the hierarchy that con‐
277 tains widget, finds the active tab group (if any), and
278 makes the previous tab group the active tab group in
279 the hierarchy.
280 · Traversal to any widget. In this case the widget argument is the
282 widget to which XmProcessTraversal tries to give focus. If the
283 widget is not traversable, XmProcessTraversal returns False.
284 Following are the possible values of the direction argument:
286 · XmTRAVERSE_CURRENT—Finds the hierarchy and the tab
288 group that contain widget. If this tab group is not
289 the active tab group, this action makes it the active
290 tab group. If widget is an item in the active tab
291 group, this action makes it the active item. If widget
292 is the active tab group, this action makes the first
293 traversable item in the tab group the active item.
294 CAUTIONS
296 Using XmProcessTraversal to traverse to MenuBars, Pulldown menu panes,
297 or Popup menu panes is not supported.
298 XmProcessTraversal cannot be called recursively. In particular, an
300 application cannot call this routine from an XmNfocusCallback or XmN‐
301 losingFocusCallback procedure.
302
304 Returns True if the traversal action succeeded. Returns False if the
305 XmNkeyboardFocusPolicy of the nearest shell ancestor of widget is not
306 XmEXPLICIT, if the traversal action finds no traversable widget to
307 receive focus, or if the call to the routine has invalid arguments.
308
310 XmGetVisibility(3) and XmIsTraversable(3).
311 XmProcessTraversal(library call)