How do I create an x by y grid and how do I color each grid section?

I am currently creating the game stratego on matlab. I am not sure how to physically create the game board though. I am looking for something quite simple, just a grid pattern where I can manually color each square whatever color I want. Please help

[Ryan Burrows]

When I plug in your code, I get the checkered board, but all the white spaces are green, and your A(10,10)=4 statement doesn't change anything. Do you have any suggestions, getting rid of the colormap turns the white spaces to yellow and the black spaces to blue. I am not sure if that helps or not. Please let me know what I did wrong and how I can fix it. Thanks

[jonas]

Put the line

A(10,10) = 4

before the line with pcolor. Sorry for the confusion.

[Ryan Burrows]

That works better, but I think I may not be understanding something about how the code works. I though that A(10,10) = a number with that square turning whatever number it corresponds to in the color pallet. So when I try to turn that square blue

 A(10,10) = 2.8

but that just turns the center square green and everything else normal. And when I do

if true
  % A(10,10) = 2.5

then it turns the center square green, then every other white square red and I am not sure why. While I have your attention, if I put multiple A(x,y) = statements to change multiple tiles different colors will I get an error statement? If so how would I change multiple squares?

[jonas]

Well you understood how this works much faster than most people do. The only thing I forgot to mention is that the colorscale scales automatically, meaning that the max/min in your matrix become the the top/bottom colors of your colorbar. You need to set the CLim so that the max/min stays at [0 4], even if those numbers are not present in your matrix.

A = repmat([repmat([1 0],1,10);repmat([0 1],1,10)],10,1)
set(gca,'clim',[0 4])
A(10,10)=3; 
h = pcolor(A)

cmap = [0 0 0;1 1 1;1 0 0;0 0 1;0 1 0];
colormap(cmap)
set(gca,'clim',[0 4])

In addition, something you will probably find useful is that you can change the colors after plotting by this simple syntax

h.CData(2,4) = 3

assuming the handle to your pcolor is called h. This will be useful for you when you move your pieces over the board. You can write a callback function for that.

[Walter Roberson]

pcolor() is really surf() followed by view(2).

pcolor() interpolates face colors according to the surrounding four nodes.

If you want face colors directly you should be using imagesc()

Answer 1

[jonas]

You could use pcolor, here's a checkerboard example

A = repmat([repmat([1 0],1,10);repmat([0 1],1,10)],10,1)
pcolor(A)

You can build a color palette like this

cmap = [0 0 0;1 1 1;1 0 0;0 0 1;0 1 0];
colormap(cmap)

Now you can paint with these colors, by assigning values between, for example, 0 and 4 (you have 5 colors).

A(10,10)=4;

Makes the square at [10;10] green