Question: How does margin support work?

[leandrosilva]

Hey you guys! :)

I see a lot of printers saying media-*-margin-supported = 423. I myself have one here as follow:

    "media-col-default": {
        "media-size": {
            "x-dimension": 21000,
            "y-dimension": 29700
        },
        "media-top-margin": 423,
        "media-bottom-margin": 423,
        "media-left-margin": 423,
        "media-right-margin": 423,
        "media-source": "auto",
        "media-type": "stationery",
        "duplex-supported": 0
    },
    "media-left-margin-supported": 423,
    "media-right-margin-supported": 423,
    "media-top-margin-supported": 423,
    "media-bottom-margin-supported": 423,

But I have seen some throughout the Internet with different values as an array like:

'media-right-margin-supported': [428, 423, 421, 445, 406, 432, 433, 419].

OK. My question is: Does that mean the given printer supports only the specified list of values?

I wondering this because I'm trying to print a PDF with zero margin but the printer is applying 423 no matter what:

    var msg = {
        'operation-attributes-tag': {
            'requesting-user-name': 'codezone',
            'job-name': 'test',
            'document-format': 'application/pdf'
        },
        'job-attributes-tag': {
            'media-col': {
                'media-source': 'tray-1',
                'media-type': 'stationery',
                'media-size': {
                    'x-dimension': 14800,
                    'y-dimension': 21000
                },
                'media-top-margin': 0,
                'media-bottom-margin': 0,
                'media-left-margin': 0,
                'media-right-margin': 0
            },
            'margins-pre-applied': true,
            'orientation-requested': 'portrait'
        },
        data: data
    };

I appreciate any help.

Thanks!

[michaelrsweet]

@leandrosilva The "media-xxx-margin-supported" attributes report the supported values for all media sizes. In many printers, different media sizes have different margins - for example, HP printers historically had left/right margins of .25 inch for US Letter but .135 inch for A4 (both yielding an 8 inch printable width). You know which margins go with which sizes by looking at the "media-col-database" and "media-col-ready" attributes (the latter listing the media that is actually loaded in the printer). Margins for some printers can also vary depending on the print mode, for example when doing 2-sided printing.

Now, media margins are a separate thing from document margins (like what you have in a PDF file). Printers can use the page size and margin information in an input document (e.g. PDF file) to scale/offset the document for printing - the "print-scaling" attribute (when supported) provides some control over this.

A printer that does not support borderless (media-xxx-margin=0) printing physically cannot print all the way to the edge of the sheet (even if you specify 0 margins in the print request), so typically a borderless PDF file (like a full-bleed brochure) will get clipped at the edges unless you tell the printer to scale (via the "print-scaling" attribute).

[leandrosilva]

Thank you @michaelrsweet