Re: [Gimp-print-devel] More API thoughts

[Michael S. <mi...@ea...>]

Robert L Krawitz wrote:
>    Date: Wed, 18 Feb 2004 08:02:05 -0500
>    From: Michael Sweet <mi...@ea...>
>    Cc: we...@ti..., gim...@li...,
>       ber...@st...
> 
>    Robert L Krawitz wrote:
>    > ...
>    >    Are there planes to describe the channel in its color meaning. How
>    >    does the driver know which channel to give the data if someone says
>    >    V: vert.  An enumeration is as well not allways clear. The CMYKRB
>    >    is an good example about semantic. More mixes will maybe
>    >    introduced.
>    > 
>    > Right, but we're not going to solve every problem right away.  This is
>    > an interim solution.
> 
>    One way to do this using an enumeration is to define the color
>    space value as a bitwise OR of colors, e.g. use 4 bits to describe
>    the colorant, with 0 meaning no color.  Um, like so:
> 
> 	0000 = no color
> 	0001 = black
> 	0010 = red
> 	0011 = green
> 	0100 = yellow
> 	0101 = blue
> 	0110 = magenta
> 	0111 = cyan
> 	1000 = white (yes, there are printers with white)
> 	...
> 
> 	RGB  = 0000 0101 0011 0010      = 0x00000532
> 	CMY  = 0000 0100 0110 0111      = 0x00000467
> 	CMYK = 0000 0001 0100 0110 0111 = 0x00001467
> 	...
> 
> This is really intended to be only an interim solution.  My guess is
> that there won't be a lot of really strange things for a while, and
> that will give us time to devise a better solution.  Anyway, this list
> is incomplete also; there are CMYKOG (orange) ink sets, also.

Right, but the format would support 15 different colorants
and up to 8 channels (for 32-bit integers, anyways) in a
very compact and efficient format; whether you make full use
of it right away is your call, but it would allow for future
growth without major API changes.

-- 
______________________________________________________________________
Michael Sweet, Easy Software Products           mike at easysw dot com
Printing Software for UNIX                       http://www.easysw.com