Can Subplots have own colormaps?

I must be missing something obvious.. but I can get each subplots colorbars to plot with its own colormap? Here is my code:

RGB = imread('FleursLilac.png');

[X,cmap] = rgb2ind(RGB,32);

RGB2 = imread('Brown.jpg');

[X2,cmap2] = rgb2ind(RGB2,32);

A = reshape(1:36, 6, 6); % A = reshape(1:256, 16, 16);

subplot(1,4,1)

imshow(RGB)

title('Original RGB Image')

subplot(1,4,2);

imshow(RGB2);

title('Target Image')

colormap(cmap2);

colorbar;

subplot(1,4,3);

imagesc(A);

colormap(cmap);

colorbar;

title('Colormap A')

subplot(1,4,4);

imagesc(A);

colormap(cmap);

colorbar;

title('Colormap B')

And here is the result, in all its glory...

"Ideally", Colormap A and B should correspond to each respective images from which is was extracted.

Answer 1

[DGM]

Yes, but you have to be careful. By default, colormap() applies to the current figure. If you want it to apply to the current axes alone, you can specify the axes object.

RGB = imread('flowers.png');
[X,cmap] = rgb2ind(RGB,32);

RGB2 = imread('shoes.png');
[X2,cmap2] = rgb2ind(RGB2,32);

A = reshape(1:36, 6, 6);  % A = reshape(1:256, 16, 16);
subplot(2,2,1)
imshow(RGB)
title('Original RGB Image')

subplot(2,2,2);
imshow(RGB2);
title('Target Image')
colormap(cmap2);
colorbar; 

hax = subplot(2,2,3);
image(A);
colormap(hax,cmap);
colorbar;
title('Colormap A')

hax = subplot(2,2,4);
image(A);
colormap(hax,cmap2);
colorbar;
title('Colormap B')

Two things to note: First, I reordered the subplots so that it would be readable on the forum. Second, since the swatch charts are basically indexed color images, we should be using image() instead of imagesc() so that the colormapping is direct. Alternatively, if using imshow(), you would use something like

imshow(A,cmap)
colorbar;

instead of calling colormap() explicitly.