Insufficient description of output filter draw:luminance and draw:contrast

[Regina Henschel <rb.henschel@t-online.de>]

Hi all,

compared with draw:blue the description of draw:luminance and 
draw:contrast is not sufficient to implement these attributes.

Please read the specification of "20.94 draw:blue" and then compare it 
with those from "20.105 draw:contrast" and "20.135 draw:luminance":
"The draw:luminance attribute specifies a signed percentage value that 
sets the output luminance of a bitmap or raster graphic."
"The draw:contrast attribute specifies a signed percentage value that 
sets the output contrast of a bitmap or raster graphic."

These attributes do not "set" luminance or contrast. But both attributes 
are used in a mapping of the original RGB-values to the output 
RGB-values, together with the draw:red, draw:green and draw:blue values.

Kind regards
Regina