ColorFunction
Usage Message: ColorFunction is an option for various graphics functions which specifies a function to apply to z
values to determine the color to use for a particular x, y region. Attributes[ColorFunction] = {Protected}
Notes: ColorFunction is an option in ContourGraphics
, ContourPlot
, DensityGraphics
, DensityPlot
, ListContourPlot
, ListDensityPlot
, ListPlot3D
, Plot3D
, Raster
, and SurfaceGraphics
. In ContourGraphics
, ContourPlot
, and ListContourPlot
, if the contour levels are given by a list c the argument passed to the value of the ColorFunction option for each contour will be
0.0, 1.0, or (c[[k]] + c[[k-1]] - First[c] - z1)/(z2 - z1 + Last[c] - First[c]) for k=2 through Length[c], where
z1 and z2 are specified by the value of the PlotRange
option. In DensityGraphics
, DensityPlot
, and ListDensityPlot
, the argument passed to the value of the ColorFunction option for each cell is given by (z - z1)/(z2 - z1), where z is the value in
the cell, and z1 and z2 are specified by the PlotRange
option. In ListPlot3D
, Plot3D
, and SurfaceGraphics
, the argument passed to the value of the ColorFunction option for each rectangle will be (z - z1)/(z2 - z1), where z is the average of
the values at the corners of a rectangle, and z1 and z2 are specified by the PlotRange
option. A useful device for studying the arguments that are passed to the ColorFunction option is to include an operation such as AppendTo
in the value of the ColorFunction option to record those arguments. For example:
In[1]:= {z1, z2} = {-1, 5};
In[2]:= c = {1.0, 1.5, 2.0,2.5, 3.0};
In[3]:= cf = {};
In[4]:= ContourPlot[x, {x, 0, 4}, {y, 0, 1},
PlotRange -> {z1, z2},
Contours -> c,
ColorFunction :> ((AppendTo[cf, #]; GrayLevel[#]) &)]
Out[4]= -ContourGraphics-
Here are the arguments that were passed to the value of the ColorFunction option, and for comparison the arguments computed using the values
of the Contours
and PlotRange
options.
In[5]:= cf
Out[5]= {0.3125, 0.4375, 0.5625, 0.6875, 0., 1.}
In[6]:= Join[Table[(c[[k]] + c[[k-1]] - First[c] - z1)/
(z2 - z1 + Last[c] - First[c]), {k, 2, Length[c]}],
{0.0, 1.0}]
Out[6]= {0.3125, 0.4375, 0.5625, 0.6875, 0., 1.}
Additional Online Documentation:
Mathematica 3.0
http://documents.wolfram.com/v3/RefGuide/ColorFunction.html
Mathematica 4.0
http://documents.wolfram.com/v4/RefGuide/ColorFunction.html
Questions or comments? Send email to support@wolfram.com.
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