[R] pixmapIndexed color question

[Uwe Ligges]

Christoph Lehmann wrote:

> Hi
> 
> I use pixmapIndexed
> 
> tmp.vimp <- array(0,c(x.dim,y.dim))
> tmp.vimp <- pixmapIndexed(tmp.vimp, col=rainbow)
> 
> to plot values of a 2D matrix. I 'fill' the pixmapIndexed like:
> 
>     for (x in 1:x.dim) {
>         for (y in 1:y.dim) {
>                     tmp.vimp at index[x,y] <- my.matrix[x,y]
>     }}

I guess you are going to call it like this:
   pixmapIndexed(my.matrix, col=rainbow)

If you change the data after the call to pixmapIndexed(), the color 
information won't be calculated again. See the function definition 
itself for details (as well as the help page).

Uwe Ligges


> 
> how can I define, that the colors are painted e.g. according the rainbow 
> palette?
> 
> plot(tmp.vimp) paints all 'pixels' in red even though I specified it 
> with col=rainbow (see above)
> 
> many thanks
> 
> cheers
> 
> christoph
> 
> p.s. is there an easier method for 'painting' the values of a 2d matrix?
> 
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