1 This is ../info/external-widget.info, produced by makeinfo version 4.6
2 from external-widget.texi.
4 INFO-DIR-SECTION XEmacs Editor
6 * External Widget: (external-widget) External Client Widget.
10 File: external-widget.info, Node: Top, Next: Using an External Client Widget, Up: (dir)
12 An "external client widget" is a widget that is part of another
13 program but functions as an Emacs frame. This is intended to be a more
14 powerful replacement for standard text widgets.
18 * Using an External Client Widget::
19 * External Client Widget Resource Settings::
20 * Motif-Specific Info About the External Client Widget::
21 * External Client Widget Internals::
24 File: external-widget.info, Node: Using an External Client Widget, Next: External Client Widget Resource Settings, Prev: Top, Up: Top
26 Using an External Client Widget
27 *******************************
29 There are three different implementations of the external client widget.
30 One is designed for use in Motif applications and is linked with the
31 option `-lextcli_Xm'. Another is designed for non-Motif applications
32 that still use the X toolkit; it is linked with the option
33 `-lextcli_Xt'. The third is designed for applications that do not use
34 the X toolkit; it is linked with the option `-lextcli_Xlib'. In order
35 to use an external client widget in a client program that uses the X
36 toolkit (i.e. either of the first two options described above), simply
37 create an instance of widget type ExternalClient and link your program
38 with the appropriate library. The corresponding header file is called
41 Documentation still needs to be provided for using the raw Xlib
42 version of the external client widget.
44 The external client widget will not do anything until an instance of
45 Emacs is told about this particular widget. To do that, call the
46 function `make-frame', specifying a value for the frame parameter
47 `window-id'. This value should be a string containing the decimal
48 representation of the widget's X window ID number (this can be obtained
49 by the Xt function `XtWindow()'). In order for the client program to
50 communicate this information to Emacs, a method such as sending a
51 ToolTalk message needs to be used.
53 Once `make-frame' has been called, Emacs will create a frame that
54 occupies the client widget's window. This frame can be used just like
55 any other frame in Emacs.
58 File: external-widget.info, Node: External Client Widget Resource Settings, Next: Motif-Specific Info About the External Client Widget, Prev: Using an External Client Widget, Up: Top
60 External Client Widget Resource Settings
61 ****************************************
63 The external client widget is a subclass of the Motif widget XmPrimitive
64 and thus inherits all its resources. In addition, the following new
65 resources are defined:
67 `deadShell (class DeadShell)'
68 A boolean resource indicating whether the last request to the
69 ExternalShell widget that contains the frame corresponding to this
70 widget timed out. If true, no further requests will be made (all
71 requests will automatically fail) until a response to the last
72 request is received. This resource should normally not be set by
75 `shellTimeout (class ShellTimeout)'
76 A value specifying how long (in milliseconds) the client should
77 wait for a response when making a request to the corresponding
78 ExternalShell widget. If this timeout is exceeded, the client
79 will assume that the shell is dead and will fail the request and
80 all subsequent requests until a response to the request is
81 received. Default value is 5000, or 5 seconds.
83 The shell that contains the frame corresponding to an external client
84 widget is of type ExternalShell, as opposed to standard frames, whose
85 shell is of type TopLevelShell. The ExternalShell widget is a direct
86 subclass of Shell and thus inherits its resources. In addition, the
87 following new resources are defined:
89 `window (class Window)'
90 The X window ID of the widget to use for this Emacs frame. This is
91 normally set by the call to `x-create-frame' and should not be
94 `deadClient (class DeadClient)'
95 A boolean resource indicating whether the last request to the
96 corresponding ExternalClient widget timed out. If true, no further
97 requests will be made (all requests will automatically fail) until
98 a response to the last request is received. This resource should
99 normally not be set by the user.
101 `ClientTimeout (class ClientTimeout)'
102 A value specifying how long (in milliseconds) the shell should wait
103 for a response when making a request to the corresponding
104 ExternalClient widget. If this timeout is exceeded, the shell
105 will assume that the client is dead and will fail the request and
106 all subsequent requests until a response to the request is
107 received. Default value is 5000, or 5 seconds.
109 Note that the requests that are made between the client and the shell
110 are primarily for handling query-geometry and geometry-manager requests
111 made by parent or child widgets.
114 File: external-widget.info, Node: Motif-Specific Info About the External Client Widget, Next: External Client Widget Internals, Prev: External Client Widget Resource Settings, Up: Top
116 Motif-Specific Info About the External Client Widget
117 ****************************************************
119 By default, the external client widget has navigation type
122 The widget traversal keystrokes are modified slightly from the
123 standard XmPrimitive keystrokes. In particular, `<TAB>' alone does not
124 traverse to the next widget (`Ctrl-<TAB>' must be used instead), but
125 functions like a normal <TAB> in Emacs. This follows the semantics of
126 the Motif text widget. The traversal keystrokes `Ctrl-<TAB>' and
127 `Shift-<TAB>' are silently filtered by the external client widget and
128 are not seen by Emacs.
131 File: external-widget.info, Node: External Client Widget Internals, Prev: Motif-Specific Info About the External Client Widget, Up: Top
133 External Client Widget Internals
134 ********************************
136 The following text is lifted verbatim from Ben Wing's comments in
139 This is a special Shell that is designed to use an externally-
140 provided window created by someone else (possibly another process).
141 That other window should have an associated widget of class
142 ExternalClient. The two widgets communicate with each other using
143 ClientMessage events and properties on the external window.
145 Ideally this feature should be independent of Emacs. Unfortunately
146 there are lots and lots of specifics that need to be dealt with for
147 this to work properly, and some of them can't conveniently be handled
148 within the widget's methods. Some day the code may be rewritten so
149 that the embedded-widget feature can be used by any application, with
150 appropriate entry points that are called at specific points within the
153 This feature is similar to the OLE (Object Linking & Embedding)
154 feature provided by MS Windows.
156 Communication between this shell and the client widget:
158 Communication is through ClientMessage events with message_type
159 EXTW_NOTIFY and format 32. Both the shell and the client widget
160 communicate with each other by sending the message to the same window
161 (the "external window" below), and the data.l[0] value is used to
162 determine who sent the message.
164 The data is formatted as follows:
166 data.l[0] = who sent this message: external_shell_send (0) or
167 external_client_send (1) data.l[1] = message type (see enum
168 en_extw_notify below) data.l[2-4] = data associated with this message
170 EventHandler() handles messages from the other side.
172 extw_send_notify_3() sends a message to the other side.
174 extw_send_geometry_value() is used when an XtWidgetGeometry structure
175 needs to be sent. This is too much data to fit into a
176 ClientMessage, so the data is stored in a property and then
177 extw_send_notify_3() is called.
179 extw_get_geometry_value() receives an XtWidgetGeometry structure
182 extw_wait_for_response() is used when a response to a sent message
183 is expected. It looks for a matching event within a particular
186 The particular message types are as follows:
188 1) extw_notify_init (event_window, event_mask)
190 This is sent from the shell to the client after the shell realizes
191 its EmacsFrame widget on the client's "external window". This tells
192 the client that it should start passing along events of the types
193 specified in event_mask. event_window specifies the window of the
194 EmacsFrame widget, which is a child of the client's external window.
196 extw_notify_init (client_type)
198 When the client receives an extw_notify_init message from the shell,
199 it sends back a message of the same sort specifying the type of the
200 toolkit used by the client (Motif, generic Xt, or Xlib).
202 2) extw_notify_end ()
204 This is sent from the shell to the client when the shell's
205 EmacsFrame widget is destroyed, and tells the client to stop passing
208 3) extw_notify_qg (result)
210 This is sent from the client to the shell when a QueryGeometry
211 request is received on the client. The XtWidgetGeometry structure
212 specified in the QueryGeometry request is passed on in the
213 EXTW_QUERY_GEOMETRY property (of type EXTW_WIDGET_GEOMETRY) on the
214 external window. result is unused.
216 In response, the shell passes the QueryGeometry request down the
217 widget tree, and when a response is received, sends a message of type
218 extw_notify_qg back to the client, with result specifying the
219 GeometryResult value. If this value is XtGeometryAlmost, the returned
220 XtWidgetGeometry structure is stored into the same property as above.
221 [BPW is there a possible race condition here?]
223 4) extw_notify_gm (result)
225 A very similar procedure to that for extw_notify_qg is followed when
226 the shell's RootGeometryManager method is called, indicating that a
227 child widget wishes to change the shell's geometry. The
228 XtWidgetGeometry structure is stored in the EXTW_GEOMETRY_MANAGER
231 5) extw_notify_focus_in (), extw_notify_focus_out ()
233 These are sent from the client to the shell when the client gains or
234 loses the keyboard focus. It is done this way because Xt maintains its
235 own concept of keyboard focus and only the client knows this
242 Node: Using an External Client Widget
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243 Node: External Client Widget Resource Settings
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244 Node: Motif-Specific Info About the External Client Widget
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245 Node: External Client Widget Internals
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