function Tangram_mzip
%   MATLAB zip file, a self-extracting MATLAB archive.
%   Usage: Run this file to recreate the original directory.

    fname = mfilename;
    fin = fopen([fname '.m'],'r');
    dname = fname(1:find(fname=='_',1,'last')-1);
    mkdir(dname);
    mkdir([dname filesep 'lib'])
    addpath(dname)
    addpath([dname filesep 'lib'])    
    
    L = fgetl(fin);
    while length(L) < 2 || ~isequal(L(1:2),'%%')
        L = fgetl(fin);
    end
    while ~isequal(L,'%% EOF')
        F = [dname filesep L(4:end)];
        disp(F)
        fout = fopen(F,'w');
        L = fgetl(fin);
        while length(L) < 2 || ~isequal(L(1:2),'%%')
            fprintf(fout,'%s\n',L);
            L = fgetl(fin);
        end
        fclose(fout);
    end
    fclose(fin);
end
%% Tangram.m
function P = Tangram
    % Tangram  Tangram puzzle
    
    % Copyright 2014-2025 Cleve Moler
    
    i = 1i;
    triangle = @(s) [-s-s*i s-s*i 0 -s-s*i];
    square = @(s) [0 s s+s*i s*i 0];
    parallelogram = @(s) [-2*s-2*s*i 0-2*s*i s-s*i -s-s*i -2-2*s*i];
    
    T{1} = triangle(2);
    T{2} = triangle(2);
    T{3} = triangle(sqrt(2));
    T{4} = triangle(1);
    T{5} = triangle(1);
    T{6} = square(sqrt(2));
    T{7} = parallelogram(1);
    
    init_plot(T);
    xit = init_buttons;
    if nargout >= 0
        return
    end
    
    while xit.Value == 0
        drawnow
    end
    close(gcf)

% ------------------------

    function button_motion(varargin)
        % Button motion, either drag or rotate a piece.
        % Use complex arithmetic.

        point = get(gca,'currentpoint');
        v = point(1,1) + point(1,2)*1i;
        hit = get(gca,'userdata');
        if ~isempty(hit) && ishandle(hit) && hit ~= 1
            u = get(hit,'xdata') + get(hit,'ydata')*1i;
            z = get(hit,'userdata');
            % Check if closer to center or vertex.
            w  = mean(u(1:end-1));
            if abs(w-v) < min(abs(u-v))
                % Drag
                u = u - (z - v);
            else
                % Rotate about the center by an integer
                % multiple of pi/20, which is 9 degrees.
                dtheta = pi/20;
                theta = angle(v-w) - angle(z-w);
                theta = round(theta/dtheta)*dtheta;
                omega = exp(1i*theta);
                u = omega*(u-w) + w;
                v = omega*(z-w) + w;
            end
            set(hit,'xdata',real(u),'ydata',imag(u),'userdata',v);
        end
    end

    function init_plot(T)
        % Initialize primary plot.
        clf
        shg
        h = 5.5;
        w = 11;
        set(gcf,'position',[100 100 800 400], ...
            'numbertitle','off', ...
            'menubar','none', ...
            'name','Tangram')
        ax = axes( ...
            'color',get(gcf,'color'), ...
            'xlim',[-w w], ...
            'ylim',[-h h], ...
            'userdata',[]);
        hold on
        axis off equal
        colors = dark_2;
        init_shift = [-2.25-1i 2.25-1i -2.5+1.5i 0.5+1i ...
            3.5+1i -2.5+2i 2.5+4i];
        for k = 1:7
            t = T{k} + init_shift(k);
            P{k,1} = fill(real(t),imag(t),colors(k,:), ...
                'markeredgecolor','black', ...
                'linewidth',2, ...
                'tag',int2str(k));
        end

        x = [-w w w -w -w];
        y = [-h -h h h -h];
        plot(x,y,'k-','linewidth',3)

        set(gcf,'userdata',ax)
    end

    function xit = init_buttons(varargin)
        % Initialize buttons and callbacks.
        set(gcf, ...
            'windowbuttondownfcn',@button_down, ...
            'windowbuttonmotionfcn',@button_motion, ...
            'windowbuttonupfcn',@button_up)
        fs = 12;
        x = 0.72;
        y = 0.14;
        bgc = [1 1 1];
        uicontrol( ...
            'units','normalized', ...
            'position',[x y+.24 .16 .06], ...
            'style','pushbutton', ...
            'fontsize',fs, ...
            'fontweight','bold', ...
            'string','info', ...
            'backgroundcolor',bgc, ...
            'callback',@info)
        uicontrol( ...
            'units','normalized', ...
            'position',[x y+.16 .16 .06], ...
            'style','pushbutton', ...
            'fontsize',fs, ...
            'fontweight','bold', ...
            'string','restart', ...
            'backgroundcolor',bgc, ...
            'callback',@restart_cb)
        uicontrol( ...
            'units','normalized', ...
            'position',[x y+.08 .16 .06], ...
            'style','pushbutton', ...
            'fontsize',fs, ...
            'fontweight','bold', ...
            'string','flipper', ...
            'backgroundcolor',bgc, ...
            'callback',@flipper)
        xit = uicontrol( ...
            'units','normalized', ...
            'position',[x y .16 .06], ...
            'style','pushbutton', ...
            'fontsize',fs, ...
            'fontweight','bold', ...
            'backgroundcolor',bgc, ...
            'string','exit', ...
            'callback','close(gcf)');
    end

    function restart_cb(varargin)
        ex = findobj('string','exit');
        set(ex,'value',1);
        Tangram;
    end

    function button_down(varargin)
        % Select a piece and remember it in userdata.
        point = get(gca,'currentpoint');
        z = point(1,1) + point(1,2)*1i;
        delete(findobj(gca,'type','line'))
        h = flipud(get(gca,'children'));
        hit  = [];
        for k = 1:length(h)
            x = get(h(k),'xdata');
            y = get(h(k),'ydata');
            if inregion(real(z),imag(z),x,y)
                hit = h(k);
                set(hit,'userdata',z)
                break
            end
        end
        set(gca,'userdata',hit)
        h = 5.5;
        w = 11;
        x = [-w w w -w -w];
        y = [-h -h h h -h];
        line(x,y,'color','k','linewidth',3)
    end

    function button_up(varargin)
        % Button up, snap to any nearby piece, then deselect.
        % Use complex arithmetic.

        delete(findobj(gca,'type','line'))
        hit = get(gca,'userdata');
        set(gca,'userdata',[])

        % Compute distance to nearest vertex of other pieces.

        z = get(hit,'xdata') + get(hit,'ydata')*1i;
        h = get(gca,'children');
        w = [];
        for k = 1:length(h)
            if h(k) ~= hit
                w = [w; get(h(k),'xdata')+get(h(k),'ydata')*1i];
            end
        end
        dz = 1;
        for k = 1:length(z)
            d = z(k)-w;
            dw = d(find(abs(d)==min(abs(d)),1));
            if abs(dw) < abs(dz)
                dz = dw;
            end
        end

        % If close enough, snap to nearby piece.

        tol = 0.5;
        if abs(dz) < tol
            set(hit,'xdata',real(z-dz),'ydata',imag(z-dz))
            hitcolor = get(hit,'facecolor');
            set(hit,'facecolor',min(1.25*hitcolor,1.0))
            set(hit,'facecolor',min(1.25*hitcolor,1.0))
            pause(1.5)
            set(hit,'facecolor',hitcolor)
        end
        h = 5.5;
        w = 11;
        x = [-w w w -w -w];
        y = [-h -h h h -h];
        line(x,y,'color','k','linewidth',3)
    end

    function info(~,~)
        web('https://blogs.mathworks.com/cleve/')
    end
end
%% lib\flipper.m
function flipper(~,~)
    P7 = findobj(gca,'tag','7');
    fc = P7.FaceColor;
    P7.FaceColor = fc/max(fc);
    x = P7.XData; 
    x = 2*mean(x(1:end-1))-x;
    pause(2)
    P7.XData = x;
    pause(2)
    P7.FaceColor = fc;
end
%% lib\snap.m
function snap(hit)
    % Button up, snap to any nearby piece, then deselect.
    % Use complex arithmetic.
    
    % Compute distance to nearest vertex of other pieces.
    
    z = get(hit,'xdata') + get(hit,'ydata')*1i;
    h = get(gca,'children');
    w = [];
    for k = 2:length(h)
        if h(k) ~= hit
            w = [w; get(h(k),'xdata')+get(h(k),'ydata')*1i];
        end
    end
    dz = 1;
    for k = 1:length(z)
        d = z(k)-w;
        dw = d(find(abs(d)==min(abs(d)),1));
        if abs(dw) < abs(dz)
            dz = dw;
        end
    end
    
    % If close enough, snap to nearby piece.
    
    tol = 0.5;
    if abs(dz) < tol
        set(hit,'xdata',real(z-dz),'ydata',imag(z-dz))
        hitcolor = get(hit,'facecolor');
        set(hit,'facecolor',min(1.25*hitcolor,1.0))
        pause(1.5)
        set(hit,'facecolor',hitcolor)
    end
end
%% lib\tanmove.m
function tanmove(who,x,y)
    v = get(who,'vertices');
    w = v + [x,y];
    set(who,'vertices',w)
end
%% lib\tanrot.m
function tanrot(who,deg)
    v = get(who,'vertices');
    mu = mean(v(1:end-1,:));
    R = [cosd(deg) sind(deg); -sind(deg) cosd(deg)];
    w = (v - mu)*R + mu;
    set(who,'vertices',w)
end
%% EOF