Re: gEDA-user: PCB produces invalid postscript

[DJ Delorie <dj@xxxxxxxxxxx>]

> I asked what the gray is supposed to be. You say that it depends on
> the gamma setting of my X software. Supposing is an action of human
> mind. Does it mean that the person who decided the postscript
> generation can not only remotely read the setting of my X server,
> but can also do it against the flow of time?

No, I meant the software can NOT tell what your X server and monitor
are set for, so it can NOT pre-determine exactly what "grey" means.

> What do you mean with "display 50% grey"? 50% of what? 50% of voltage
> range on the monitor input, 50% of the numerical range in the video
> card, 50% or numerical range in the X application's output range,
> or 50% of maximum photon flux?

I'm sorry, I didn't realize you knew so little about calibrating
monitors.

Display an image that, on one side, is filled a pixel value halfway
between white and black.  On the other side, fill it with half white
pixels and half black pixels.  Now, adjust your X/monitor/whatever
until the two halves are visually similar in intensity.  You now have
a linear gamma response.

> This does have to do with PCB that I am asking what grey the grey
> was meant to be. If you want to make the grey with little black spots
> on white paper, how many % of area are the black spots going to
> take?

You see, the problem is, you keep saying "the grey" as if there's only
one.  There isn't only one.  You're not giving us enough information.
Let me put on my mystic mind reader hat and see if I can figure out
what you *really* want the answer to...

"How do you calculate the intensity of the faded colors used in the
assembly drawing?"

For Postscript HID output it's 20% (pigment-wise) of whatever the
original color was, in the case of the assembly drawing.  I.e. one
part original color mixed with four parts white.  If you need to
change it, search for CBLEND in src/hid/ps/ps.c

For the old Gtk version, it appears to be 10%.

Why don't you just look at the postscript output and find out for
yourself?  Just search for the "setgray" or "setrgbcolor" and see what
numbers it's using.