Display

Displays are output devices, which do not require claiming.

• For CloudPRNT Version HTTP

• For CloudPRNT Version MQTT (Trigger POST)

  Status information is reported inside the usual Polling the server (POST) from the client to the server,

  Display messages can be passed back by the server inside the JSON POST response.

• For CloudPRNT Version MQTT (Full MQTT / Pass URL)

  Status information is reported in client-status message.

  Display messages can be specified by the CloudPRNT server using the output-to-display message.

Inside the JSON Request or client-status message, a display field will provide an array of JSON objects in the following format:

{
    "name": "<device logical name>",
    "status": { "connected": bool }
}

• “name”

  Specifies a logical device name to uniquely identify the display.

  This name may be used to claim the “display” in order to send a message to show on the display device.

• “status”

  an object describing the device status, containing a field:

  • “connected”

    a Boolean value, true if the display is physically connected and false otherwise.

Sending messages to the display, is handled by specifying a display field in the JSON Response form the server back to the client.

For CloudPRNT Version MQTT (Full MQTT / Pass URL) , specified in the display field of the output-to-display message.

Messages are strings which can use a simple markup format.

Command	Function
[cls]	Clear display, and reset cursor to home position.
[home]	Reset cursor to home position.
[nl]	New Line, moves cursor to the beginning of the next line.
[http://…] [https://…]	Display image from URL. The CloudPRNT device will download a PNG or Jpeg image from the specified url and draw to the display (If image display is supported).
[enc <encoding>]	Set display text encoding to <encoding>.

he markup language is sent as plain text strings through JSON, which will be displayed directly.

Special commands can be embedded inside the square bracket ‘[’ ‘]’ sets.

Escaping is supported for characters which might otherwise not be possible to insert.

The characters ‘’, ‘[’ and ‘]’ can be escaped with the sequences “”, “[” and “]” respectively.

Hex data sequences can be inserted with the escape “xHH”, where “HH” is a double digit hex value.