[Therion] Redefining PENA...PEND to draw lighter

[Footleg]

It should be quite a simple job to adjust the black point for a bitmap to
make any shade of grey truly black. It you have a bitmap editor with a
levels control, you can adjust the end points of the black-white range of
image. At the extreme you can compress the entire brightness range into
just black and white (no grey in between), but with a small range you can
get a grey scale scan looking pretty black and white.

Footleg

On Tue, 19 May 2015 07:35 Bruce <bruce at tomo.co.nz> wrote:

> Thanks for asking that question Michael
> I have the same problem, but I had not bothered to think about changing the
> linework colour.
>
> I just tried a simpler approach (that leaves the header and grid
> coordinates
> black).  I will use this from now on.
>
>    symbol-colour group all [60] #makes everything grey
>    colour map-fg [97 86 38] #add some colour
>
> And check out this code to make the grid grey
>
> http://therion.speleo.sk/wiki/doku.php/metapost?s[]=change&s[]=grid&s[]=symb
> ols#special_symbol_examples
> <http://therion.speleo.sk/wiki/doku.php/metapost?s[]=change&s[]=grid&s[]=symbols#special_symbol_examples>
> Code to change grid symbols from cross hairs to continuous lines
>
> Thanks
> Bruce
> (I don't know how to change the pen colours)
>
>
> -----Original Message-----
> From: therion-bounces at speleo.sk [mailto:therion-bounces at speleo.sk] On
> Behalf
> Of Michael Wasmund
> Sent: Tuesday, 19 May 2015 12:00 p.m.
> To: therion at speleo.sk
> Subject: [Therion] Redefining PENA...PEND to draw lighter
>
>
> Hello,
> Does someone have metapost code to redefine PENA...PEND to draw grey
> instead
> of black?
>
> Why I need this:
>
> My survey consists of 80% scanned bitmaps and 20% drawn scraps.
> The bitmaps are "grey", not black (can't make them better using image
> processing).
>  The drawn scraps then stand out and look ugly compared to the bitmaps.
>
> I know how to redefine individual symbols (walls etc.) to be grey instead
> of
> black,
> but rather than redefining a large symbol set I'd rather redefine the PENs
> -
> if possible.
>
> Regards,
> Michael.
>
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