|
428
|
1 @c -*-texinfo-*-
|
|
|
2 @c This is part of the XEmacs Lisp Reference Manual.
|
|
|
3 @c Copyright (C) 1998 Oliver Graf <ograf@fga.de>
|
|
444
|
4 @c Original reference is (c) 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
|
|
428
|
5 @c See the file lispref.texi for copying conditions.
|
|
|
6 @setfilename ../../info/dragndrop.texi
|
|
|
7 @node Drag and Drop, Modes, Scrollbars, Top
|
|
|
8 @chapter Drag and Drop
|
|
|
9 @cindex drag and drop
|
|
|
10
|
|
|
11 @emph{WARNING}: the Drag'n'Drop API is still under development and the
|
|
|
12 interface may change! The current implementation is considered experimental.
|
|
|
13
|
|
|
14 Drag'n'drop is a way to transfer information between multiple applications.
|
|
|
15 To do this several GUIs define their own protocols. Examples are OffiX, CDE,
|
|
|
16 Motif, KDE, MSWindows, GNOME, and many more. To catch all these protocols,
|
|
|
17 XEmacs provides a generic API.
|
|
|
18
|
|
|
19 One prime idea behind the API is to use a data interface that is
|
|
|
20 transparent for all systems. The author thinks that this is best
|
|
|
21 archived by using URL and MIME data, cause any internet enabled system
|
|
|
22 must support these for email already. XEmacs also already provides
|
|
|
23 powerful interfaces to support these types of data (tm and w3).
|
|
|
24
|
|
|
25 @menu
|
|
|
26 * Supported Protocols:: Which low-level protocols are supported.
|
|
|
27 * Drop Interface:: How XEmacs handles a drop from another application.
|
|
|
28 * Drag Interface:: Calls to initiate a drag from XEmacs.
|
|
|
29 @end menu
|
|
|
30
|
|
|
31 @node Supported Protocols
|
|
|
32 @section Supported Protocols
|
|
|
33
|
|
|
34 The current release of XEmacs only support a small set of Drag'n'drop
|
|
|
35 protocols. Some of these only support limited options available in the API.
|
|
|
36
|
|
|
37 @menu
|
|
|
38 * OffiX DND:: A generic X based protocol.
|
|
|
39 * CDE dt:: Common Desktop Environment used on suns.
|
|
|
40 * MSWindows OLE:: Mr. Gates way of live.
|
|
|
41 * Loose ends:: The other protocols.
|
|
|
42 @end menu
|
|
|
43
|
|
|
44 @node OffiX DND
|
|
|
45 @subsection OffiX DND
|
|
|
46 @cindex OffiX DND
|
|
|
47
|
|
|
48 @emph{WARNING}: If you compile in OffiX, you may not be able to use
|
|
|
49 multiple X displays successfully. If the two servers are from
|
|
|
50 different vendors, the results may be unpredictable.
|
|
|
51
|
|
|
52 The OffiX Drag'n'Drop protocol is part of a X API/Widget library created by
|
|
|
53 Cesar Crusius. It is based on X-Atoms and ClientMessage events, and works with
|
|
|
54 any X platform supporting them.
|
|
|
55
|
|
|
56 OffiX is supported if 'offix is member of the variable dragdrop-protocols, or
|
|
|
57 the feature 'offix is defined.
|
|
|
58
|
|
|
59 Unfortunately it uses it's own data types. Examples are: File, Files,
|
|
444
|
60 Exe, Link, URL, MIME. The API tries to choose the right type for the data that
|
|
428
|
61 is dragged from XEmacs (well, not yet...).
|
|
|
62
|
|
444
|
63 XEmacs supports both MIME and URL drags and drops using this API. No application
|
|
428
|
64 interaction is possible while dragging is in progress.
|
|
|
65
|
|
|
66 For information about the OffiX project have a look at http://leb.net/~offix/
|
|
|
67
|
|
|
68 @node CDE dt
|
|
|
69 @subsection CDE dt
|
|
|
70 @cindex CDE dt
|
|
|
71
|
|
|
72 CDE stands for Common Desktop Environment. It is based on the Motif
|
|
|
73 widget library. It's drag'n'drop protocol is also an abstraction of the
|
|
|
74 Motif protocol (so it might be possible, that XEmacs will also support
|
|
|
75 the Motif protocol soon).
|
|
|
76
|
|
|
77 CDE has three different types: file, buffer, and text. XEmacs only uses
|
|
|
78 file and buffer drags. The API will disallow full URL drags, only file
|
|
|
79 method URLs are passed through.
|
|
|
80
|
|
|
81 Buffer drags are always converted to plain text.
|
|
|
82
|
|
|
83 @node MSWindows OLE
|
|
|
84 @subsection MSWindows OLE
|
|
|
85 @cindex MSWindows OLE
|
|
|
86
|
|
|
87 Only allows file drags and drops.
|
|
|
88
|
|
|
89 @node Loose ends
|
|
|
90 @subsection Loose ends
|
|
|
91
|
|
|
92 The following protocols will be supported soon: Xdnd, Motif, Xde (if I
|
|
|
93 get some specs), KDE OffiX (if KDE can find XEmacs windows).
|
|
|
94
|
|
|
95 In particular Xdnd will be one of the protocols that can benefit from
|
|
|
96 the XEmacs API, cause it also uses MIME types to encode dragged data.
|
|
|
97
|
|
|
98 @node Drop Interface
|
|
|
99 @section Drop Interface
|
|
|
100 @cindex drop
|
|
|
101 @cindex Drop API
|
|
|
102
|
|
904
|
103 For each activated low-level protocol, an internal routine will catch
|
|
428
|
104 incoming drops and convert them to a dragdrop-drop type
|
|
|
105 misc-user-event.
|
|
|
106
|
|
|
107 This misc-user-event has its function argument set to
|
|
|
108 @code{dragdrop-drop-dispatch} and the object contains the data of the drop
|
|
|
109 (converted to URL/MIME specific data). This function will search the variable
|
|
444
|
110 @code{experimental-dragdrop-drop-functions} for a function that can handle the
|
|
428
|
111 dropped data.
|
|
|
112
|
|
|
113 To modify the drop behavior, the user can modify the variable
|
|
|
114 @code{experimental-dragdrop-drop-functions}. Each element of this list
|
|
|
115 specifies a possible handler for dropped data. The first one that can handle
|
|
|
116 the data will return @code{t} and exit. Another possibility is to set a
|
|
|
117 extent-property with the same name. Extents are checked prior to the
|
|
|
118 variable.
|
|
|
119
|
|
|
120 The customization group @code{drag-n-drop} shows all variables of user
|
|
444
|
121 interest.
|
|
428
|
122
|
|
|
123 @node Drag Interface
|
|
|
124 @section Drag Interface
|
|
|
125 @cindex drag
|
|
|
126 @cindex Drag API
|
|
|
127
|
|
|
128 This describes the drag API (not implemented yet).
|
