[tei-council] facsimile diagram

[Conal Tuohy]

On Fri, 2007-08-03 at 07:26 +0100, James Cummings wrote:
> Conal Tuohy wrote:
> > It's true I didn't mean to imply that a graphic could act as a zone - I
> > don't think people should in general be linking bits of text to those
> > graphics.
> 
> So really people should only be linking to and from zones generally.

yes

> > Within the same <surface/> as the stamp's <zone/>, there would be some
> > <graphic/> elements, and if those graphics had @coords which overlapped
> > the @coords of the stamp's zone, then those graphics would actually
> > depict the stamp itself. Any of those associated graphics might be used
> > to present a view of that zone. Obviously a graphic whose coords
> > entirely enclosed the coords of the zone would be best (because it will
> > show the full stamp), and a graphic whose resolution is higher will be
> > better (if zooming), etc.
> 
> Ok, and if those graphic/@coords are relative to the surface, how do we on the 
> surface indicate what unit of measurement they are using?  Surely a surface may 
> be measured in all sorts of units (millimetres, inches, metres, 
> kilometres,etc.)?  

Well, it's not really needed in order to align the graphics and the
zones (all that's needed is that the units are consistent). But for
documentary purposes, perhaps a surface's dimensions could be given
using a <dimensions> element?

> How do I know that one graphic is higher resolution than the 
> other?  i.e. they both cover the same area of the surface "0 0 100 100" but one 
> was taken with a hi-res camera, and one was taken quite awhile ago with some 
> low-res camera.  How is that resolution indicated?

The 2 graphics may use @height and @width to indicate their intrinsic
dimensions. The hi-res image should be higher and wider, despite having
the same @coords as the equivalent lo-res image. The resolution of a
graphic could be calculated by dividing the @width by the width as
specified in the @coords (which says how much of the surface the graphic
covers). 

But to be honest, rereading the documentation for @height, @width and
@scale, I'm not entirely sure that I understand how @height and @width
are supposed to work together with @scale. 
http://www.tei-c.org/release/doc/tei-p5-doc/html/ref-graphic.html

If I have an image which is 200px wide, I would expect to mark it up as
a graphic with @width="200px", but what do I do with @scale? And what is
the "desired display size" anyway? If I give @scale="2", I'd be saying
that I wanted the image to be displayed as 400 pixels wide, which sounds
like an odd thing to want to do.

I'd be interested in seeing any examples of the use of @scale.

As an alternative to calculations involving graphic/@height, etc,
presentation software could choose among graphics on the basis of
metadata encoded in a linked <surrogates> element. Could that be a
useful approach?

Con