Re: [PyMOL] effect of number of pixels on ray image quality

[Ezequiel H P. <za...@pa...>]

yvonne leduc wrote:
> I would like some confirmation or explanation about the differences I=20
> see, and the way I understand it.
Hello Yvonne,

The command "ray" does not care about the size of your display, it may=20
even be used in batch mode on a computer that does not have a monitor=20
attached to it at all.

To prevent the "cropping"  or "zooming" on images created by the "ray"=20
command you have to make sure that the aspect ratio of the width and=20
height of the ray command are the same as the aspect ratio of your=20
current viewport.

Example 1)
	if you will be rendering (thats what the command ray does)
	figures of 2000 x 2000 you should choose a viewport of
	say 700x700, then:

	2000 / 2000 =3D 1 =3D 700 / 700

    - so you should execute the command:

	viewport 700, 700

    - and then fine tune your figure and then run the ray command:

	ray 2000, 2000


Exmaple 2)
     - you want images at 3000 Width x 2000 Height

	3000 / 2000 =3D 1.5

    - your limiting display size is your height so
      try for instance height =3D 768

	width =3D height * 1.5 =3D 768 * 1.5 =3D 1152

    - but 1152 is wider than your display (1024) so lets try height =3D 5=
00

	width =3D 500 * 1.5 =3D 750 (which is good now, or at least it fits)

   - so you would issue the command

	viewport 750, 500

   - then ray 3000, 2000

> And the reason for all this is ...
> ... is a *.png image created with ray 1000,750 going to be good enough=20
> for publication standards?  Is there much benefit in going higher?  wha=
t=20
> causes the limits, if any?

The journal usually specifies the resolution at which the images will be=20
printed.

If the journal says images print at 300 dpi (Dots Per Inch) and your=20
figure will have a final printed width of 3 inches then you want to=20
render images with a width of 900.

The publisher will usually scale the picture with a very good software=20
so even if it has to be "enlarged" by a few pixels the result will be=20
good. But if it has to be shrinked you may run into trouble with labels,=20
thin lines etc.

Hope this helped a bit.

Zac
--=20
Ezequiel PANEPUCCI, Ph.D. - Institut Pasteur
Plate-Forme 6 - Cristallog=E9n=E8se et Diffraction des Rayons X
Telephone: +33 (0)1 44 38 94 57
Portable:  +33 (0)6 13 14 39 06