Display - display a document
[file] Display(in mediaType contents [in title docName]);
Document and Media Exchange Message Sets Display(4)
NAME
Display - display a document
SYNOPSIS
[file] Display(in mediaType contents
[in title docName]);
DESCRIPTION
The Display request causes the handler to display (present or manifest)
a document to the user. For example, an audio manipulation utility
would be said to ``display'' audio documents when it plays them.
The handler must decide issues such as:
o When the display operation can be deemed completed
o What user gesture signals the completion of the display
o What the handling tool should do with itself after replying
The contents argument is the contents of the document. If this argu-
ment is unset (in other words, has a value of (char *)0), then the con-
tents of the document are in the file named in the message's file
attribute. The data type (mediaType) of the contents argument should
be string, unless nulls are valid in the given media type, in which
case the data type must be bytes.
The docName argument contains the name of the document. If the docName
argument is absent and the file attribute is set, the file name is con-
sidered to be the title of the document. This string would be suitable
for display in a window title bar, for example.
APPLICATION USAGE
The ttmedia_ptype_declare(3) function can be used to register for, and
help process, this message.
This message can be sent with the ttmedia_load(3) function.
When the document to be displayed is read-only or unlikely to be modi-
fied the Display message is frequently used instead of the Edit mes-
sage.
EXAMPLES
To display a PostScript document, the application can send a Display
request with a first argument whose vtype is PostScript, and whose
value is a vector of bytes such as:
%!\n/inch {72 mul} def...
The \n in the example represents the newline character.
To display a PostScript document contained in a file, the application
can send a Display request with the file attribute set to that file and
with an unset first argument whose vtype is PostScript.
ERRORS
The ToolTalk service may return one of the following errors in process-
ing the Display request:
TT_DESKTOP_ENOENT
The file that was alleged to contain the document does not
exist.
TT_DESKTOP_ENODATA
The in-mode contents argument had no value and the file
attribute of the message was not set.
TT_MEDIA_ERR_FORMAT
The document is not a valid instance of the media type.
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
+---------------+------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+------------------+
|Availability | library/tooltalk |
+---------------+------------------+
|Stability | Committed |
+---------------+------------------+
SEE ALSO
ttmedia_ptype_declare(3), ttmedia_load(3); Intro, Deposit, Edit, Status
requests.
ToolTalk 1.3 1 March 1996 Display(4)