[cups.general] Fixing the page-label option

[Johannes Meixner]

Hello,

On Sep 29 13:07 Johannes Meixner wrote (shortened):
> Assume the content of a page has
> %%BoundingBox 10 15 580 780
> it means the content is from left 10 to right 580 on the x axis
> and from bottom 15 to top 780 on the y axis.
....
> Use the %%BoundingBox values to place the content "inside"
> of the paper but use the %%Orientation value to find out
> how a user would orientate the printed paper in front
> of his face to view the content.
....
> %%BoundingBox 15 10 780 580
> %%Orientation Portrait
> means:
> the user would orientate the printed paper so that the longest edge
> of the paper is vertical.
....
> Examples:
>
> Assume one big capital letter 'L' should be printed.
>
> If the PostScript content is (ASCII fixed-font-size graphics):
>
>  #
>  #
>  #
>  ###
>
> or
>
>  ###
>    #
>    #
>    #
>
> the DSC comments must be like
> %%BoundingBox 10 15 580 780
> %%Orientation Portrait
....
> The examples also show that %%Orientation values like "Seascape"
> and "UpsideDown" are missing.

Meanwhile I think that %%Orientation values like "Seascape"
and "UpsideDown" are not missing.

Reasoning:

When
%%BoundingBox 10 15 580 780
means the content is from left 10 to right 580 on the x axis
and from bottom 15 to top 780 on the y axis
then the orientation of the content is already defined.

Therefore
if the PostScript content is (ASCII fixed-font-size graphics):

y axis

^
|
|
|  #
|  #
|  #
|  ###
|
0---------> x axis

the DSC comments would be like
%%BoundingBox 10 15 580 780
%%Orientation Portrait
which means that the user orientates the printed paper so that
the longest edge of the printed paper is vertical
and
(because the orientation of the content is already defined
by the PostScript coordinate system) those longest edge
of the printed paper which matches to a zero x value in
the PostScript coordinate system (i.e. those longest edge of
the printed paper which matches to the y axis in the PostScript
coordinate system) must be on the left when the user orientates
the printed paper.

If the PostScript content is (ASCII fixed-font-size graphics):

y axis

^
|
|
|  ###
|    #
|    #
|    #
|
0---------> x axis

the DSC comments would be exactly the same like
%%BoundingBox 10 15 580 780
%%Orientation Portrait
which means that the user again has to orientate the printed paper
exactly the same as above because the orientation of the content
is already defined by the PostScript coordinate system.

This means that the content in the first case displays one big
capital letter 'L' in "usual" orientation and in the latter case
the content displays one big capital letter 'L' in some kind
of upside-down orientation or perhaps it should display even
a mirror-inverted capital Greek "gamma" letter.

In the end what I mean is that the PostScript coordinate system
plus the %%Orientation value are perhaps sufficient to completely
determine how the user must orientate a printed paper to view the
content exactly as it is intended by the one who created the
PostScript.

Think about an abstract painting which one gets as PostScript
with DSC comments. It should be unambiguous how a printout
has to be orientated.

But now I wonder what to do
if the PostScript content is (ASCII fixed-font-size graphics):

y axis

^
|
|      #
|  #####
|
0-------------> x axis

with those DSC comments:
%%BoundingBox 15 10 780 580
%%Orientation Portrait

Is this PostScript content meant to display one big capital
letter 'L' in "usual" orientation or alternatively one big
capital letter 'L' in some kind of upside-down orientation
or a mirror-inverted capital Greek "gamma" letter?

How must the user orientate the printed paper in this case
to view the content as it is actually meant?


Kind Regards
Johannes Meixner
-- 
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