How to change distanceUnit to something besides points?

[contactzero]

Sorry if this has been asked before. I don't find my answer in (BatchPlay) format.

I want to pass a variable in PIXELS, for instance,  instead of 1417 POINTS in this batchPlay script.

How do I specify the distanceUnit? (pixels, inches, centimeters, etc)

            {
              "_obj": "canvasSize",
              "width": {
                 "_unit": "distanceUnit",  //How to specify pixels or centimeters or inches??
                 "_value": 1417 //<<< POINTS
              },
              "height": {
                 "_unit": "distanceUnit",
                 "_value": 5817   //<<< POINTS
              },
              "horizontal": {
                 "_enum": "horizontalLocation",
                 "_value": "center"
              },
              "vertical": {
                 "_enum": "verticalLocation",
                 "_value": "center"
              },
              "_isCommand": true
           },         

 TIA