Re: [Gimp-print-devel] Left margin must not be less than 9.000000

[Ken M. <zar...@nt...>]

On Tue, Sep 29, 2020 at 12:34:50AM +0100, Ken Moffat via Gimp-print-devel wrote:
> On Mon, Sep 28, 2020 at 04:58:28PM -0400, Robert Krawitz wrote:
> > On 9/28/20 3:29 PM, Ken Moffat via Gimp-print-devel wrote:
> > > Hi,
> > > 
> > > I hope this is the right list to ask for help.  I've got an Epson
> > > Photo R360 using 5.3.3 with cups-2.3.3 and gimp-2.10.20.  Ordinary
> > > printing of text and photos appears to be ok, but -
> > > 
> > > I'm hoping to print some (tiny) signs for a model, white text on
> > > blue background.  At this point I'm guessing about sizes, so I've
> > > set up a page of A4 dimensions in gimp (actually 209.97 x 297.01
> > > millimetres), put a big blue panel across the top part of the page,
> > > and inserted various white text.
> > > 
> > > But when I use 'print with gutenprint' and tell it to use the image
> > > size, I get: two messages:
> > > 
> > >  Left margin must not be less than 9.000000
> > > 
> > > and
> > > 
> > >  Print options not verified, cannot print.
> > > 
[...]
> > 
> > You also need to set the Borderless option to true.
> > 
> 
> Robert,
> 
> thanks for that (second screen of cups, Printer Features Common),
> 
> Unfortunately, it did not appear to make a difference.  Meanwhile
> I'd already moved some of the text so that I could fill larger
> margins with white (and that too had made no difference).
> 
> But on this modified file I now tried printing upside down (the
> bottom is already empty) and that worked (strictly, it queued the
> print which I cancelled - I need to remove a lot of the blue and add
> some lining before doing real output).  Very weird.
> 

I think I might have found the root cause - roundings in gimp.
Just mentioning it here in case google's indexing turns up this
thread.

Today I spent some time painting at the individual pixel level, and
also blanking out areas to reduce the amount of ink used in testing.
Got to a stage where I thought it was worth printing to review the
sizes.  The same problem as originally.  I was able to export as a
PDF, and then print that from epdfview (so, using the gutenprint
driver, but set for plain paper and standard quality).  And the area
I was printing has decent margins.

So, I looked again at the image size in millimetres: I had specified
210x297, but the length had rounded up to 297 point something (width
was 209 point something), probably because pixels per inch is fixed
at 300 in gimp.

Created a new image which was a little smaller, pasted the area with
the text into that, success in printing with gutenprint using actual
image size (i.e. I can select the media and quality at the time I
print).

Fun!

ĸen
-- 
A really good hydrophobe has to be trained on dehydrated water from
birth.  I mean, that costs a fortune in magic alone.  But they make
great weather magicians.  Rain clouds just give up and go away.
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