A rainbow analog clock animation in MATLAB for my ENGIN-136 class.

RainbowClock.m

% Final Project: Rainbow Analog Clock
% Author: Tejas Shah
% Class: ENGIN-136 - Intro to MATLAB

% Clear any vars and current figure and show it on top of screen
clear, clf, shg

% Setup drawing board for clock
axis([-1.1 1.1 -1.1 1.1]);
axis square
axis off

% Used for 1-second markings
sec_x = sin(2*pi*(1:60)/60);
sec_y = cos(2*pi*(1:60)/60);

% Used for 5-second markings
sec_marks = 5:5:60;

% Draw border of clock with 1 second markings
line(sec_x, sec_y,...
    'LineStyle', 'none',...
    'Marker', 'o',...
    'Color', 'black',...
    'MarkerSize', 2);
line(sec_x(sec_marks), sec_y(sec_marks),...
    'LineStyle', 'none',...
    'Marker', '*',...
    'Color', 'red',...
    'MarkerSize', 8);

% Draw 5-second markings
for i = 1:length(sec_marks)
    x_pos = 1.1 * (sec_x(sec_marks(i)) - 0.05);
    y_pos = 1.1 * (sec_y(sec_marks(i)));
    text(x_pos, y_pos, num2str(i), 'fontsize', 16);
end

% Initialize the various time hands
hour = RainbowLine(20, 4);
min = RainbowLine(20, 4);
sec = RainbowLine(20, 2);
msec = RainbowLine(20, 1);

% Add a close button
close_btn = uicontrol('string', 'close', 'style', 'toggle');

% Increases drawing speed by using any available hardware for openGL
% acceleration. If not present, it'll default to using the software version
opengl hardware

while ishandle(close_btn) && ~get(close_btn, 'value')
    c = clock;
    
    % Draw the datetime text below the clock
    datetime_text = text(0, -1.2,...
        datestr(datetime('now')),...
        'FontSize', 16,...
        'HorizontalAlignment', 'center');
    
    % Draw hours hand
    t = c(4)/12 + c(5)/(60 * 12) + c(6)/(60 * 60 * 12);
    hour.Draw([0 0.8*sin(2*pi*t)], [0 0.8*cos(2*pi*t)], [0 .3]);
    
    % Draw minutes hand
    t = c(5)/60 + c(6)/(60 * 60);
    min.Draw([0 sin(2*pi*t)], [0 cos(2*pi*t)], [.5 .8]);
    
    % Draw seconds hand, changing its color based on second
    t = floor(c(6)) / 60;
    sec.Draw([0 sin(2*pi*t)], [0 cos(2*pi*t)], t);
    
    % Draw milliseconds hand
    t = floor((c(6) - floor(c(6))) * 1000) / 1000;
    msec.Draw([0 0.5*sin(2*pi*t)], [0 0.5*cos(2*pi*t)], t);
    
    % Force draw the figure to update hand positions
    % NOTE: average draw time is 10 ms +/- 5 ms
    drawnow;
    
    % Delete the datetime text for redrawing it after current loop iteration
    delete(datetime_text);
end

% Close the figure once we're done
close(gcf);

RainbowLine.m

classdef RainbowLine < handle
    properties
        X
        Y
        NumPoints
        LineWidth
        LineHandle
    end
    
    methods
        function obj = RainbowLine(NumPoints, LineWidth)
            % set colormap to HSV to properly draw the rainbow effect
            colormap(hsv);
            
            % by default, the color axis will scale based on the colors
            % that are drawn, based on the HSV scale from 0 to 1
            
            % ex. if the colors present are from 0 to 0.8, and all of a
            % sudden, a 0.9 appears, the color axis is automatically scaled
            % to 0 to 0.9, affecting all the other drawn colors
            caxis('manual')
            
            % Number of points for linear spacing generation
            obj.NumPoints = NumPoints;
            obj.LineWidth = LineWidth;
            
            % Initialize the line handle
            obj.Draw([0 0], [0 0]);
        end
        
        function obj = Draw(obj, X, Y, CRange)
            % Compute the linspace for X and Y
            obj.X = linspace(X(1), X(2), obj.NumPoints);
            obj.Y = linspace(Y(1), Y(2), obj.NumPoints);
            
            XData = [obj.X; obj.X];
            YData = [obj.Y; obj.Y];
            
            % Create an array of zeros for the Z axis (no 3D drawing)
            z = zeros(size(obj.X));
            ZData = [z; z];
            
            if ~exist('CRange', 'var'); CRange = [0 1]; end
            if length(CRange) == 1; CRange = [CRange CRange]; end
            
            % The color range is from 0 to 1, via HSV, so make a series of
            % colored points from red to orange to yellow to green to cyan
            % to blue to purple back to red with the same amount of points
            col = linspace(CRange(1), CRange(2), obj.NumPoints);
            ColorData = [col; col];
            
            if ~ishandle(obj.LineHandle)
                % Create line handle if it doesn't exist
                obj.LineHandle = surface(...
                    XData, YData, ZData, ColorData,...
                    'FaceColor', 'none',...
                    'EdgeColor', 'interp',...
                    'LineWidth', obj.LineWidth);
            else
                % Update existing line handle with new data
                obj.LineHandle.XData = XData;
                obj.LineHandle.YData = YData;
                obj.LineHandle.CData = ColorData;
            end
        end
    end
end