--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+grid/Ti.m	Thu Sep 17 10:12:50 2015 +0200
@@ -0,0 +1,201 @@
+classdef Ti
+    properties
+        gs % {4}Curve
+        S  % FunctionHandle(u,v)
+    end
+
+    methods
+        % TODO function to label boundary names.
+        %  function to find largest and smallest delta h in the grid. Maybe shouldnt live here
+        function obj = Ti(C1,C2,C3,C4)
+            obj.gs = {C1,C2,C3,C4};
+
+            g1 = C1.g;
+            g2 = C2.g;
+            g3 = C3.g;
+            g4 = C4.g;
+
+            A = g1(0);
+            B = g2(0);
+            C = g3(0);
+            D = g4(0);
+
+            function o = S_fun(u,v)
+                x1 = g1(u);
+                x2 = g2(v);
+                x3 = g3(1-u);
+                x4 = g4(1-v);
+                o1 = (1-v).*x1(1,:) + u.*x2(1,:) + v.*x3(1,:) + (1-u).*x4(1,:) ...
+                    -((1-u)*(1-v).*A(1,:) + u*(1-v).*B(1,:) + u*v.*C(1,:) + (1-u)*v.*D(1,:));
+                o2 = (1-v).*x1(2,:) + u.*x2(2,:) + v.*x3(2,:) + (1-u).*x4(2,:) ...
+                    -((1-u)*(1-v).*A(2,:) + u*(1-v).*B(2,:) + u*v.*C(2,:) + (1-u)*v.*D(2,:));
+
+                o = [o1;o2];
+            end
+
+            obj.S = @S_fun;
+        end
+
+        function [X,Y] = map(obj,u,v)
+            default_arg('v',u);
+
+            if isscalar(u)
+                u = linspace(0,1,u);
+            end
+
+            if isscalar(v)
+                v = linspace(0,1,v);
+            end
+
+            S = obj.S;
+
+            nu = length(u);
+            nv = length(v);
+
+            X = zeros(nv,nu);
+            Y = zeros(nv,nu);
+
+            u = rowVector(u);
+            v = rowVector(v);
+
+            for i = 1:nv
+                p = S(u,v(i));
+                X(i,:) = p(1,:);
+                Y(i,:) = p(2,:);
+            end
+        end
+
+        function h = plot(obj,nu,nv)
+            S = obj.S;
+
+            default_arg('nv',nu)
+
+            u = linspace(0,1,nu);
+            v = linspace(0,1,nv);
+
+            m = 100;
+
+            X = zeros(nu+nv,m);
+            Y = zeros(nu+nv,m);
+
+
+            t = linspace(0,1,m);
+            for i = 1:nu
+                p = S(u(i),t);
+                X(i,:) = p(1,:);
+                Y(i,:) = p(2,:);
+            end
+
+            for i = 1:nv
+                p = S(t,v(i));
+                X(i+nu,:) = p(1,:);
+                Y(i+nu,:) = p(2,:);
+            end
+
+            h = line(X',Y');
+        end
+
+
+        function h = show(obj,nu,nv)
+            default_arg('nv',nu)
+            S = obj.S;
+
+            if(nu>2 || nv>2)
+                h_grid = obj.plot(nu,nv);
+                set(h_grid,'Color',[0 0.4470 0.7410]);
+            end
+
+            h_bord = obj.plot(2,2);
+            set(h_bord,'Color',[0.8500 0.3250 0.0980]);
+            set(h_bord,'LineWidth',2);
+        end
+
+
+        % TRANSFORMATIONS
+        function ti = translate(obj,a)
+            gs = obj.gs;
+
+            for i = 1:length(gs)
+                new_gs{i} = gs{i}.translate(a);
+            end
+
+            ti = grid.Ti(new_gs{:});
+        end
+
+        % Mirrors the Ti so that the resulting Ti is still left handed.
+        %  (Corrected by reversing curves and switching e and w)
+        function ti = mirror(obj, a, b)
+            gs = obj.gs;
+
+            new_gs = cell(1,4);
+
+            new_gs{1} = gs{1}.mirror(a,b).reverse();
+            new_gs{3} = gs{3}.mirror(a,b).reverse();
+            new_gs{2} = gs{4}.mirror(a,b).reverse();
+            new_gs{4} = gs{2}.mirror(a,b).reverse();
+
+            ti = grid.Ti(new_gs{:});
+        end
+
+        function ti = rotate(obj,a,rad)
+            gs = obj.gs;
+
+            for i = 1:length(gs)
+                new_gs{i} = gs{i}.rotate(a,rad);
+            end
+
+            ti = grid.Ti(new_gs{:});
+        end
+
+        function ti = rotate_edges(obj,n);
+            new_gs = cell(1,4);
+            for i = 0:3
+                new_i = mod(i - n,4);
+                new_gs{new_i+1} = obj.gs{i+1};
+            end
+            ti = grid.Ti(new_gs{:});
+        end
+    end
+
+    methods(Static)
+        function obj = points(p1, p2, p3, p4)
+            g1 = grid.Curve.line(p1,p2);
+            g2 = grid.Curve.line(p2,p3);
+            g3 = grid.Curve.line(p3,p4);
+            g4 = grid.Curve.line(p4,p1);
+
+            obj = grid.Ti(g1,g2,g3,g4);
+        end
+
+        function label(varargin)
+            if nargin == 2 && ischar(varargin{2})
+                label_impl(varargin{:});
+            else
+                for i = 1:length(varargin)
+                    label_impl(varargin{i},inputname(i));
+                end
+            end
+
+
+            function label_impl(ti,str)
+                S = ti.S;
+
+                pc = S(0.5,0.5);
+
+                margin = 0.1;
+                pw = S(  margin,      0.5);
+                pe = S(1-margin,      0.5);
+                ps = S(     0.5,   margin);
+                pn = S(     0.5, 1-margin);
+
+
+                ti.show(2,2);
+                grid.place_label(pc,str);
+                grid.place_label(pw,'w');
+                grid.place_label(pe,'e');
+                grid.place_label(ps,'s');
+                grid.place_label(pn,'n');
+            end
+        end
+    end
+end
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