Subject:
|
RE: How to dither colors
|
Newsgroups:
|
lugnet.cad
|
Date:
|
Thu, 24 Jun 1999 08:07:09 GMT
|
Viewed:
|
518 times
|
| |
|
|
John VanZwieten asked:
> What's the formula for calculating a dithered color?
>
> color 1 * ??? + color 2. What value is ???
The Ldraw FAQ (http://www.ldraw.org/FAQ/) says:
Colours
Colours are outlined in LEDIT.DOC. Two special values are 16 and 24.
16 is the 'current colour', i.e., whatever colour was specified on
the type 1 line which caused the current line to be executed.
Colour 24 is a complementary colour to the current colour, usually
the bright/dark complementary shade. So if the current colour is
dark blue, colour 24 would give bright blue.
Also, colours 256 through 511 are dithered. So if you want to
combine colours J and K, figure your colour value as
colour = (J * 16) + K + 256
The complementary colour of J is used as the complementary colour
of the dithered value. So you can control the edge colour
(somewhat) by switching J and K.
<end-quote>
LDraw uses dithering because it only had 16 colors available in
a VGA display. On modern computers having 65536 or 16 million
colors, a renderer could choose to blend the rgb color values
(like L3P does): rgb = (rgb(J)+rgb(K)) / 2
/Lars
|
|
Message has 1 Reply:
 | | Re: How to dither colors
|
| Thanks. I knew that was in there but couldn't find it. This section should be moved to (or at least referenced in) the section on Color Codes. -John Van Lars C. Hassing <lch@ccieurope.com> wrote in message news:57F1FE754246D21...@aarhus... (...) (25 years ago, 24-Jun-99, to lugnet.cad)
|
2 Messages in This Thread:
 
- Entire Thread on One Page:
- Nested:
All | Brief | Compact | Dots
Linear:
All | Brief | Compact
|
|
|
|
