How to color the colormap with a set of hexadecimal colors?

I want to colormap to plot data. I want to use a set of hexadecimal code for the colors of the plot. If I run with following code, I get the plot.

map=[1 0.9 0; 1 0.75 0; 1 0.625 0; 1 0.5 0; 1 0.375 0; 1 0.25 0; 1 0.125 0; 1 0 0];

colormap(map);

But instead I want to use the following set of hexadecimal codes for the plot, for eg.

map = ('#E1F2E3','#CDE5D2','#9CCEA7','#6CBA7D','#40AD5A','#22BB3B','#06592A');

But I run into error stating that

"Error using colormap

Colormap must have 3 columns: [R,G,B]."

How should I solve this issue, please.

Answer 1

[Dave B]

Starting in R2020b you can use the validatecolor function to convert hex to rgb (using the 'multiple' option to convert more than one color):

map = {'#E1F2E3','#CDE5D2','#9CCEA7','#6CBA7D','#40AD5A','#22BB3B','#06592A'};
cmap = validatecolor(map, 'multiple')

cmap = 7×3

0.8824 0.9490 0.8902 0.8039 0.8980 0.8235 0.6118 0.8078 0.6549 0.4235 0.7294 0.4902 0.2510 0.6784 0.3529 0.1333 0.7333 0.2314 0.0235 0.3490 0.1647

imagesc(peaks)
colormap(cmap)
colorbar

[Sujata Dhar]

Thank you very much

[Stephan]

For older versions: https://www.mathworks.com/matlabcentral/fileexchange/46289-rgb2hex-and-hex2rgb by @Chad Greene

[Toshia M]

Starting in R2024a, you can use the hex2rgb function to convert hexadecimal color codes to RGB triplets. This provides an alternative way to create a colormap from a set of hexadecimal values, but you can also use the function any time you want to calculate the equivalent RGB triplet from a hexadecimal color code.

map = {'#E1F2E3','#CDE5D2','#9CCEA7','#6CBA7D','#40AD5A','#22BB3B','#06592A'};
cmap = hex2rgb(map)

cmap = 7x3

0.8824 0.9490 0.8902 0.8039 0.8980 0.8235 0.6118 0.8078 0.6549 0.4235 0.7294 0.4902 0.2510 0.6784 0.3529 0.1333 0.7333 0.2314 0.0235 0.3490 0.1647

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You can also go the other way by calling the rgb2hex function. For example, you can convert five colors from the parula colormap to hexadecimal color codes:

p5 = parula(5);
pHex = rgb2hex(p5)

pHex = 5x1 string array
    "#3E26A8"
    "#347AFD"
    "#12BEB9"
    "#C8C129"
    "#F9FB15"

Answer 2

[Bora Eryilmaz]

You can use a function like this in a loop:

map = {'E1F2E3','CDE5D2','9CCEA7','6CBA7D','40AD5A','22BB3B','06592A'}

map = 1×7 cell array
    {'E1F2E3'}    {'CDE5D2'}    {'9CCEA7'}    {'6CBA7D'}    {'40AD5A'}    {'22BB3B'}    {'06592A'}

N = numel(map);
newMap = zeros(N,3);
for i = 1:N
    newMap(i,:) = hex2rgb(map{i});
end
newMap

newMap = 7×3

225 242 227 205 229 210 156 206 167 108 186 125 64 173 90 34 187 59 6 89 42

function result = hex2rgb(h)
d = hex2dec(h);
r = bitshift(bitand(d, 0xFF0000), -16);
g = bitshift(bitand(d, 0x00FF00),  -8);
b = bitshift(bitand(d, 0x0000FF),   0);
result = [r, g, b];
end