We have the following task: print maps with specified scale with predefined
paper template.

Template basics are implemented in UDIG and there is an opportunity to
create own templates through extension point as I see. The problem is with
scale. 

So, how to print maps on the specified template where size of map image (map
box on the template) is, let's say, fixed (18 cm on 18 cm e.g.) and scale is
specified?

The desired behavior is:
There is a map with layers. Take central coordinate of the map that is in
map editor, take scale as a parameter and calculate piece of map
(rectangular box) by "clipping" the appropriate bounding box of the map and
which fits in the map box of the template with specified dimension in cm
without dimension ratio distortion.
 Central point of the map in editor goes to the central point of map box on
the template, and consequently to the central point of map image on the
printed paper. Knowing the scale parameter, size of map box on the template
in cm, and coordinate of central point of currently visible map in the
editor we can calculate bounding box and ask renderers to draw piece of map
with this bounds to the map box, then print.
So all calculations are easy and require central coordinate of the map, size
of map box, scale.

Unclear issues:
1. How to specify exact size of map box in cm on the template
2. May be some other issues...


Current behavior is that all visible viewport of map editor fits into map
box with dimension distortion. We need an algorithm described above.

Any suggestions and advises how reachable is that functionality in limits of
current printing functionality of UDIG? I give a task to our developers to
implement this functionality and contribute to UDIG base code.

Regards, Vitali.

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