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OSD.BASIC Message Specification
- Class = OSD
- Type = BASIC
This Schema provides a method of displaying text messages to an xPL implementation.
XPL-CMND Structure
osd.basic
{
command=clear|write|exclusive|release
[text=<text to display. each line should be seperated by the \n seperator>]
[row=<display row>]
[column=<display from column>]
[delay=<seconds to display>]
}
exclusive/release allow another device to take exclusive control of the osd device. The osd device should ignore all messages from any other source while locked. exclusive/release should be sent on their own only, and be targetted at the osd device. Both should perform a clear.
XPL-TRIG Structure
osd.confirm
{
command=clear|write|exclusive|release
[text=<text to display. each line should be seperated by the \n seperator>]
[row=<display row>]
[column=<display from column>]
[delay=<seconds to display>]
}
A Trigger Message with class osd.confirm MAY be sent by the application or device to confirm the actual actions taken in displaying a given message. This confirmation message should contain the original details, with the provisions that:
If the Display Device does not support overwriting, and executes a clear each time, the Trigger message should contain command=clear rather than command=write
If the Display Device does not support indefinite display, but clears after (for example, 15 seconds) the Trigger message should contain delay=15 rather than delay=0
XPL-STAT Structure
hbeat.*
{
(hbeat items)
}
Schema Specific Notes
command is the only compulsory item.
When command=clear is used, the display device should execute a "clear screen" operation before displaying the message. It is valid to send a command=clear without any further text to display.
When command=write is used, the display device will simply process the text information, possibly overlapping any existing display. Devices are not required to support this mode of operation. When command=write is used, text is mandatory.
A Value of delay=0 should be interpreted by the application as either "maximum possible delay", or as appropriate, "do not clear". Delays are cumulative, that is, text that is placed on screen with a delay of 5 seconds will remain on screen if a subsequent message specifies a further delay.
row, column and delay should have default values appropriate to the class of display device within the device or application.