[Printing-architecture] Another Epson Question on the Common Print Dialog

peter sikking peter at mmiworks.net
Tue Mar 30 02:52:39 PDT 2010


Glen wrote:

>>> ............ We are working from the basis that printable area and
> orientation are two obvious parameters that the app must know to
> transform.
>
> This clarification states, "the app must know to transform"; thus, the
> application will, by this clarification, perform the transformation.
> Epson is specifically interested in understanding about the "how does
> the app perform the transform" and

first of all, let's define transformation: this is the act of
"putting it on paper."

how any application gets its data on paper is exactly their
expert domain. for instance: a web browser reflows the web
page content to the printable area of the page, according to
the css of the page.

there are a thousands of applications where we have no idea how
they get it on paper. a DNA database? I have no idea what
would be an appropriate representation on printed media, but
the people who write the app do.

OK, so the app needs at least the printable area (page size - margins)
to do its job. in more advanced cases (eg. centre on page), it will
have to know the page size _and_ the margins.

now, if either of these things happen in the cpd,

- media size change (eg. A4 <-> letter)
- portrait <-> landscape change
- margin change
- borderless printing (hey, nothing but a margin change, really)

the app gets notified of the new printable area, or
new page size + margins, and does the transformation again.

>>>>  2. ..... how does the application "expand" the image ?
>>>>        1. by how much ?
>>>>        2. if the image size does not equal media size, the how is
>>>>           the scale ratio of the expanding decided?
>>>>        3. what is the method used by the application to expand the
>>>>           image? There are other methods beyond simple scaling.
>
> All of these item can change from print-vendor to print-vendor and
> printer-to-printer; so it important the printer vendor to understand
> more of the details.


printer vendors are in complete control of the default paper sizes,
and their margins in the cpd via the ppd. and borderless printing
ain't nothing but a special margin.

so putting it together we can see the chain now:

- the printer (vendor) provides the paper size + borderless margins;
- users choose this paper size + borderless;
- the app transforms its data to the resulting printable area.

     --ps

         founder + principal interaction architect
             man + machine interface works

         http://mmiworks.net/blog : on interaction architecture





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