https://github.com/ajuogaaz/julia
Production of different colors in Matlab
https://github.com/ajuogaaz/julia
Last synced: 3 months ago
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Production of different colors in Matlab
- Host: GitHub
- URL: https://github.com/ajuogaaz/julia
- Owner: Ajuogaaz
- Created: 2019-10-20T15:35:30.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2019-10-21T18:01:47.000Z (over 5 years ago)
- Last Synced: 2025-01-04T14:45:10.266Z (5 months ago)
- Language: MATLAB
- Size: 1010 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# Julia
Using cmaps in matlab to display Julia Sets in different Colors
## Installation
Use any licenced version of matlab after Version of 2016
## Usage
``` matlab
function Image = showJulia(EscTime,EscVal,limits)
% SHOWJULIA Show a color image of a Julia set.
%
% function Image = showJulia(EscTime,EscVal,limits)
%
% Inputs:
% EscTime = matrix of integer escape times
% EscVal = matrix of absolute z-values at escape times
% limits = vector of rectangular region limits, as in axis()
%
% Outputs:
% Image = ny-by-nx-by-3 "truecolor" image array for use in imshow()
%
% See also IMSHOW.
[ny,nx] = size(EscTime);
x = linspace(limits(1),limits(2),nx);
y = linspace(limits(4),limits(3),ny);
% convert to real escape times for less color quantization
mask = isfinite(EscTime);
EscTime(mask) = EscTime(mask) - log(log2(EscVal(mask)));
E1 = EscTime(mask);
if isempty(E1)
Image = zeros(ny,nx,3);
else
ncolors = 2^20;
cdf = [0 histcounts(E1,'BinMethod','integers','Normalization','cdf')];
% restrict the cdf slope
for k = 2:length(cdf)
cdf(k) = min(cdf(k-1)+1e-2,cdf(k)); % avoid large color jumps
cdf(k) = max(cdf(k-1)+1e-6,cdf(k)); % avoid color flatness
end
cdf = cdf/cdf(end); % renormalize
indices = [1+floor(cdf*(ncolors-2)) ncolors];
cmap = jet(ncolors);
cmap = interp1(linspace(1,ncolors,length(indices)),...
cmap(indices,:),1:ncolors);
cmap(ncolors,:) = 0; % make top color black
Emin = min(E1);
if isempty(Emin)
Emin = 0;
end
Emax = max(EscTime(mask));
slope = (ncolors-2)/(Emax-Emin);
val = round(1 + slope*(EscTime-Emin));
val(~mask) = ncolors; % makes interior points highest (black)
Image = reshape(cmap(val,:),ny,nx,3);
end
imshow(Image,'XData',x,'YData',y);
set(gca,'YDir','normal');
axis on;
end
```
