How to make my own custom colormap?

Hello, how can I define my colormap to be with the following steps: (those are hex colors)

100% - #f8fe34
83% - #f4771e
68% - #d94015
44% - #148b3e
30% - #085a3f
15% - #41332d
0% - #010101

[Walter Roberson]

Do you want graduations between the adjacent ones, or solid colors and then a jump? So for example would you have

cmapsize = 256;   %or as passed in

NumPoints = floor(cmapsize * 15/100) - floor(cmapsize * 0/100);

part0 = [linspace(dec2hex('01'), dec2hex('41'), NumPoints).', ...
         linspace(dec2hex('01'), dec2hex('33'), NumPoints).', ...
         linspace(dec2hex('01'), dec2hex('2d'), NumPoints).']

as part of the construction?

Answer 1

[Stephen23]

Step 1: Convert HEX to Decimal

>> hex = ['#f8fe34';'#f4771e';'#d94015';'#148b3e';'#085a3f';'#41332d';'#010101']
hex =
#f8fe34
#f4771e
#d94015
#148b3e
#085a3f
#41332d
#010101
>> map = sscanf(hex','#%2x%2x%2x',[3,size(hex,1)]).' / 255
map =
    0.97255      0.99608      0.20392
    0.95686      0.46667      0.11765
    0.85098      0.25098     0.082353
   0.078431       0.5451      0.24314
   0.031373      0.35294      0.24706
     0.2549          0.2      0.17647
  0.0039216    0.0039216    0.0039216
>> rgbplot(map) % to view the values

The matrix map is a standard MATLAB colormap, and it can be used anywhere that you need a colormap. You could also interpolate its values (if you need more nodes), or set this as your default colormap, or many other operations.

Step 2: Interpolate

If you want to interpolate the colormap and place the specified nodes at the given "percent" locations:

vec = [      100;       83;       68;       44;       30;       15;        0];
hex = ['#f8fe34';'#f4771e';'#d94015';'#148b3e';'#085a3f';'#41332d';'#010101'];
raw = sscanf(hex','#%2x%2x%2x',[3,size(hex,1)]).' / 255;
N = 128;
%N = size(get(gcf,'colormap'),1) % size of the current colormap
map = interp1(vec,raw,linspace(100,0,N),'pchip');

which looks like this:

[Walter Roberson]

The user wants uneven spacing between the colors.

[Walter Roberson]

Interesting use of interp1; I didn't think of doing it that way.

[Mark Golberg]

THANK YOU!!!

[Daven Gooden]

WOW!!! Nicely Done!!!

[金山]

awesome