[Radiance-general] Image dimensions

[Gregory J. Ward]

Hi Axel,

For perspective views, the actual relation for image dimensions 
involves the tangents of the view angles, not the angles themselves.  
The relation is:

	tan(vh)/tan(vv) = x/y

For more info, see:

	http://radsite.lbl.gov/radiance/digests_html/v2n7.html#VIEW_ANGLES

-Greg

> From: "Axel Jacobs" <a.jacobs at londonmet.ac.uk>
> Date: March 2, 2005 3:33:36 PM PST
>
> Dear all,
>
> rpict with -vh 25.8083 -vv 18.6685 -x 512 -y 512 will create an image 
> of
> 367x512 pixels.
>
> If I calculate the y dimension by hand, I get:
>
> y/18.6685 = 512/25.8083
> -> y = 370.3565132
>
> This number can be rounded up or down to the nearest integer, but how 
> can
> it be rounded to 367?
>
> I started doing these hand calculation when I noticed that an image
> generated with xwrays|rtrace had a couple of extra lines down the 
> bottom
> of it which are outside of the region specified in the view file (for a
> parallel view, though).
>
> Cheers
>
> Axel