Matlab Color Vectors

Is there any website where I may obtain a list of Matlab's color vectors? I can only seem to find a website with the rgb color vectors but matlab's color vectors values are only between 0 and 1.

[Jan]

Please use the search in the forum. The previous question about RGB colors was posted only 10 hours ago.

Answer 1

[the cyclist]

RGB values are typically given on a range (0,255). You can scale those linearly to get the MATLAB range of (0,1).

Answer 2

[Walter Roberson]

"rgb color vectors" does not specify representation. MATLAB's representation is an rgb representation.

You are probably more accustomed to seeing RGB values as either hex or integers in the range 0 to 255.

To convert the 0-1 representation to 0-255 representation,

color8bit = floor(colordouble * 255);

To convert the 0-1 representation to standard hex RGB:

color8hex = sprintf('#%02X%02X%02X', floor(colordouble * 255));

[Jan]

floor(x*255) replies 255 only for 1.0.

round(x*255 + 0.5) is not biased.

[Walter Roberson]

Good point. I knew I was missing something on that boundary condition...

On the other hand, if x is 1 exactly, then round(x*255 + 0.5) will return 256 exactly, which is outside the range.

floor(x*255*(1-eps)) should be unbiased (but ugly)

[Jan]

Using UINT8 instead of ROUND cares for the 256.

But I'm not convinced. u = [12, 17, 243]; d = u / 255; u2 = UINT8(d * 255 + 0.5); Now u2 is [13, 18, 244].

[Walter Roberson]

d * 255 + 0.5 fills over the interval closed-closed interval [0,255 1/2] instead of filling over the closed-open interval [0,256) . That 1/2 slot not filled can cause values to round in to the same slot.

Answer 3

[Jan]

MATLAB's color vectors are RGB color vectors. I guess, that you have colors in UINT8 format as [12, 17, 243], and MATLAB used the DOUBLE format [0.047059, 0.066667, 0.95294].

The conversion is trivial:

uint8_RGB  = [12, 17, 243];
double_RGB = uint8_RGB / 255;

[Brittany]

Not very familiar with working in matlab colors and I wanted to define my own colormap using an Mby3 matrix but could not find useful info on how to convert RGB values to those that matlab could use....thank you!!