[Date Index] [Thread Index] [Author Index]

Re: Determine brightness of colour/Convert to GrayLevel

• To: mathgroup at smc.vnet.net
• Subject: [mg89511] Re: Determine brightness of colour/Convert to GrayLevel
• From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
• Date: Wed, 11 Jun 2008 03:19:37 -0400 (EDT)
• Organization: Uni Leipzig
• References: <g2lno3$igu$1@smc.vnet.net>
• Reply-to: kuska at informatik.uni-leipzig.de

Hi,

?ToColor

ToColor[color, form] converts color to form if form is GrayLevel, \
RGBColor or CMYKColor. Otherwise form[color] is evaluated and the \
result is expected to be a valid color directive.

Regards
   Jens

Szabolcs Horv=E1t wrote:
> Colours have several representations, such as RGBColor, CMYKColor,
> GrayLevel, etc.
>
> Is there a way to convert between these representations?  More
> specifically is there a way to convert a colour to GrayLevel?  I would
> like to determine the "brightness" of a colour to decide whether to
> display text in black or in white on top of it.
>
> Also, is there a way to convert a colour to some canonical
> representation?  A workaround I found is Lighter[colour, 0], which
> converts to RGBColor, but I was hoping that there exists a function
> meant specifically for conversion (and not
> blending/lightening/darkening).
>