Around 15 o'clock on Nov 6, Olivier Chapuis wrote:

> First why you choose to use 13 grey levels and not 16 grey levels?

So that 25%, 50% and 75% were all available.  

13 gray levels give:

  0.00%   8.33%  16.67%  25.00%  33.33%  41.67%  50.00%  
 58.33%  66.67%  75.00%  83.33%  91.67% 100.00%

16 gray levels gives:

  0.00%   6.67%  13.33%  20.00%  26.67%  33.33%  40.00%  46.67%  
 53.33%  60.00%  66.67%  73.33%  80.00%  86.67%  93.33% 100.00%

> Moreover, with 16 grey levels every thing is contained in the 16x16x16 cc.
>
> Moreover, 16 seems a better number than 13. 16 = 2^4 (may leads to
> various simplification if dithering is implemented one day).

These may well both be true, and we can re-evaluate which colors to use in 
the future if such things become relevant.

> Secondly, I do not understand the "mono"/"grey" argument to -render. I
> understand "mono"/"grey" when it is the default. However, as an
> option with a 256 PseudoColor Cmap I am totally lost ... as a
> developer.  I used XRender in my programs for displaying text (Xft)
> and icons. We have functions which can perform XRender emulation for X
> server/driver without render support.

Render provides for accelerated and network-efficient client-side text.  
Even if that text is strictly monochrome, it's still quite useful.  Doing
the emulation on the client-side will make networked applications 
significantly slower.

> Finally, I send a patch to this mailing list for an implementation of
> QueryPictIndexValues (Render proto). Are you interested? I can recheck
> it, make the patch against the current cvs I send it to [EMAIL PROTECTED]

Oh yeah, I'll go dig that up and apply it.  Thanks a bunch.

> About this, I've one trouble. It is the first / last Pixel logic in
> render/miindex.c. For me in any case at the end first = 0 and
> last = "nbr of colors" - 1. No? Why this troubling logic? 

The colormap allocator isn't required to allocate colors in any particular 
order; the logic in that function is designed to handle the case where 
colors are allocated in some random order.

Keith Packard        XFree86 Core Team        HP Cambridge Research Lab


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