Re: [Printing-architecture] [Printing-summit] Print Dialog: Preview Processing: Only A Question

[Till Kamppeter <till.kamppeter@gmail.com>]

The only things which the dialog can make use of to poll from the CUPS 
server or the printer is the PPD to list options and choices and to make 
the preview giving an impression on what at least some known options 
affect on the printout and perhaps the loaded papers sizes/types polled 
from the printer to reflect them somehow in the preview. But we always 
need to be prepared to not be able to access this info and thenm we need 
to make the best out of what we have.

    Till

Petrie, Glen wrote:
> I think the situation is like this...
> 
> The preview, in most cases, will not be generated by the printer-driver
> or by the printer itself.  Printing, that is, the rendering of physical
> page from the electronic page is a one-way process done within the
> printer-driver or within the printer. In almost all cases (maybe all
> cases), it will be a filter (that means Ghostscript) that will generate
> the preview.  The filter is taking the electronic document page (PS,
> PDF, image(jpeg, tiff, png, ...), ...) and producing an "electronic
> print page" (an image) for viewing or passing to printer-drivers (or
> printers) that process only image data.
> 
> I am not aware of a printer-driver that directly generates preview
> images.
> 
> (Just to make sure, the "printer-driver" is the software/firmware that
> takes the electronic print content and converts its into printer
> specific commands to produce physical printed pages.  For example,
> inkjet "printer-drivers" typical take in images and rasterize the image
> to PCL for HP, ESC/P for Epson, and so forth.  In this case, the
> "printer-driver" output is not displayable (unless you were to use a
> filter!))