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# isocolors

Calculate isosurface and patch colors

## Syntax

nc = isocolors(X,Y,Z,C,vertices)
nc = isocolors(X,Y,Z,R,G,B,vertices)
nc = isocolors(C,vertices)
nc = isocolors(R,G,B,vertices)
nc = isocolors(...,PatchHandle)
isocolors(...,PatchHandle)

## Description

nc = isocolors(X,Y,Z,C,vertices) computes the colors of isosurface (patch object) vertices (vertices) using color values C. Arrays X, Y, Z define the coordinates for the color data in C and must be monotonic vectors that represent a Cartesian, axis-aligned grid (as if produced by meshgrid). The colors are returned in nc. C must be 3-D (index colors).

nc = isocolors(X,Y,Z,R,G,B,vertices) uses R, G, B as the red, green, and blue color arrays (true color).

nc = isocolors(C,vertices), and nc = isocolors(R,G,B,vertices) assume X, Y, and Z are determined by the expression

`[X Y Z] = meshgrid(1:n,1:m,1:p) `

where [m n p] = size(C).

nc = isocolors(...,PatchHandle) uses the vertices from the patch identified by PatchHandle.

isocolors(...,PatchHandle) sets the FaceVertexCData property of the patch specified by PatchHandle to the computed colors.

## Examples

### Indexed Color Data

This example displays an isosurface and colors it with random data using indexed color. (See Interpolating in Indexed Color Versus Truecolor for information on how patch objects interpret color data.)

```[x y z] = meshgrid(1:20,1:20,1:20);
data = sqrt(x.^2 + y.^2 + z.^2);
cdata = smooth3(rand(size(data)),'box',7);
p = patch(isosurface(x,y,z,data,10));
isonormals(x,y,z,data,p);
isocolors(x,y,z,cdata,p);
set(p,'FaceColor','interp','EdgeColor','none')
view(150,30); daspect([1 1 1]);axis tight
camlight; lighting phong; ```

### True Color Data

This example displays an isosurface and colors it with true color (RGB) data.

```[x y z] = meshgrid(1:20,1:20,1:20);
data = sqrt(x.^2 + y.^2 + z.^2);
p = patch(isosurface(x,y,z,data,20));
isonormals(x,y,z,data,p);
[r g b] = meshgrid(20:-1:1,1:20,1:20);
isocolors(x,y,z,r/20,g/20,b/20,p);
set(p,'FaceColor','interp','EdgeColor','none')
view(150,30); daspect([1 1 1]);
camlight; lighting phong;```

### Modified True Color Data

This example uses isocolors to calculate the true color data using the isosurface's (patch object's) vertices, but then returns the color data in a variable (c) in order to modify the values. It then explicitly sets the isosurface's FaceVertexCData to the new data (1-c).

```[x y z] = meshgrid(1:20,1:20,1:20);
data = sqrt(x.^2 + y.^2 + z.^2);
p = patch(isosurface(data,20));
isonormals(data,p);
[r g b] = meshgrid(20:-1:1,1:20,1:20);
c = isocolors(r/20,g/20,b/20,p);
set(p,'FaceVertexCData',1-c)
set(p,'FaceColor','interp','EdgeColor','none')
view(150,30); daspect([1 1 1]);
camlight; lighting phong;```