Re: [Gimp-print-devel] OpenPrinting Project - Make Printer Applications Configurable

[Robert K. <rl...@al...>]

On 9/7/20 3:40 PM, Sambhav Dusad wrote:
> On Sat, Sep 5, 2020 at 11:34 PM Robert Krawitz <rl...@al... <mailto:rl...@al...>> wrote:
> 
>     We really should move this discussion to gim...@li...
>     <mailto:gim...@li...> (gimp-print was the
>     original name for the project, which started with Mike's print plugin for GIMP and was later renamed
>     to Gutenprint with the 5.0 release).
> 
> Sure, We'll move the discussion there.
> How will you review the code If I simply push my changes there? There might be many changes need to
> be made.

Create a branch for your code; we'll only merge it to the main branch when it's reviewed.

>     For filling the driver data:
> 
>     Reference the stp_image_t structure defined in include/gutenprint/image.h.  You need to write the
>     appropriate functions here.  You can see the CUPS driver implementation in
>     src/cups/rastertogutenprint.c.
> 
>     Most of these are likely to be pretty simple.  The hard one, of course, is Image_get_row().  This is
>     called by the core via stp_image_get_row().  This one's going to pull a row of raster data off the
>     queue and stick it in the provided data buffer, up to the number of bytes specified (so you don't
>     overflow the buffer) and returns a status (either OK or abort -- that's how a print can be aborted).
> 
> Yes. I've made the get_row function. To clear this out, there's no need for dimensions variables
> like left, right, etc. in the cups_image_t structure now, right? Since it will all be handled by
> PAPPL and we just have to pass the data to gutenprint.

Can the user specify a page dimension smaller than the actual paper?  If so, this will probably be
needed.

>     The raster format is either 8 or 16 byte (native ordering) K, W (inverse grayscale) RGB, CMY,CMYK,
>     or KCMY.  There's also a "raw" format, which allows specifying arbitrary channels (currently
>     supported only for Epson printers, don't worry about that for now).
> 
>     As for filling in settings, your application does that and does the necessary stp_set_* functions to
>     set up all the options.
> 
> Do we have to call stp_print for gutenprint to start printing the job? 

Yes.  See rastertogutenprint.c around line 1387.

> And I was asking for the callback function which PAPPL calls to fill the driver data structure for
> PAPPL?

That's about the raster format, correct?  See above.