Re: [xmlroff] Re: xmlroff on Windows

[Jesper S. <je...@no...>]

Tony Graham wrote:
> Jesper Stigberg wrote at  8 May 2003 14:39:29 +0200:
....
>  > Great. What do gnome-print use as a unit?
> 
> So far I've found that the PDF and PostScript outputs use different
> units.  GNOME Print is under-documented, so there may be something
> that I'm missing.
> 
> See pangogp-to-pdf.c in pangopdf/examples.
> 
>  > > What do you do in your rendering application if you want to scale the
>  > > rendered image, e.g. reduce it so a whole page appears in the window?
>  > > 
>  > 
>  > A bit simplified.
>  > 
>  > In the win32 GDI (graphics device interface), all drawing,
>  > text-output etc is done through a device-context using
>  > logical-units. What appears on the screen is measured in
>  > device-units. A device-unit==scale*logical-unit ( this mapping is
>  > done by the OS ). So by changing the scale you can get a zoom
>  > effect without changing the coordinates etc in your drawing code,
>  > or use the same code to render to a printer.
> 
> And the logical unit is a 'twip', i.e., a logical pixel?

A logical unit can be mapped to twips, pixels, mm, etc or a unit of your own.

ex:
move_to(0,0); /* (x,y), in logical units */
line_to(0,20);

this could draw a 20 pixel or a 20 twips long line, depending on what a logical 
unit is mapped to.

I don't know what a logical pixel is, a twip is, as far as I know, 1/1440 of an 
inch.

Jesper.