Re: Again: canvas size

[Ethan M. <merritt@u.washington.edu>]

On Wednesday 12 October 2005 04:45 pm, Harald Harders wrote:

> > Introduce a new coordinate system "absolute", or maybe even the specific
> > units  "in", "cm", "pt", "pixel".
> 
> I totally agree with this approach. The specific units have too problems:
> How shall pixel defined in vector terminals

I assume that you would not specify a measurement in pixels if you are
using a vector terminal.

> and how shall in, ch, pt be 
> defined in terminals without a absolute canvas size? 

Which terminals do you have in mind here - the pixel terminals?

> For png and jpeg, a 
> resolution in dpi could be given and thus in, ch, and pt also used.

I think we would have to introduce a "dpi" parameter into the various terminal
options.  There would have to be a default value, which would usually turn out
to be wrong, but what else can we do?

	set term png size 900,300  {dpi 300}
would be the same as
	set term png size 3in, 1in dpi 300

Both would generate a 3 inch by 1 inch image when printed to
a 300 dpi printer.  The first form would only require the dpi
value if you in fact wanted to use absolute coordinates in inches or cm.
The second form absolutely requires the dpi value in order to calculate
the necessary size in pixels.

> what about x11 and windows? Do they have access to the system-wide
> resolution settings?

X11 has access to the display resolution.
It is not system-wide because it can be different for each display device.


-- 
Ethan A Merritt       merritt@u.washington.edu
Biomolecular Structure Center
Mailstop 357742
University of Washington, Seattle, WA 98195