# Image dimensions

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

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

-Greg

···

From: "Axel Jacobs" <a.jacobs@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