Fix several methods setting the arc length property.

Author: gnestlinger

Path2D.m

@@ -54,7 +54,7 @@
 %   See also PolygonPath, SplinePath.
 
     properties (SetAccess = protected)
-        % ISCIRCUIT - Logical indicating if path is a circuit
+        % IsCircuit - Logical indicating if path is a circuit
         IsCircuit = false
     end
 
@@ -70,6 +70,11 @@
         %PATH2D     Construct a PATH2D class instance.
         end%Constructor
 
+        function obj = set.ArcLengths(obj, val)
+            assert(numel(val) == obj.numel())
+            obj.ArcLengths = val(:);
+        end%fcn
+        
         function s = cumlengths(obj)
         % CUMLENGTHS    Cumulative path segment lengths.
         %   S = CUMLENGTHS(OBJ) returns the vector S of cumulative path

PolygonPath.m

@@ -437,11 +437,11 @@
             % strictly increasing
             assert(all(diff(tau) > 0))
 
-            xyhcs = interp1(0:N-1, ...
+            xyhcs = interp1(...
                 [obj.x, obj.y, obj.head, obj.curv, obj.arcLengths0()], ...
-                tau(:), varargin{:});
+                tau(:) + 1, varargin{:});
             obj = PolygonPath(xyhcs(:,1), xyhcs(:,2), xyhcs(:,3), xyhcs(:,4));
-            obj.ArcLengths = xyhcs(:,5);
+            obj.ArcLengths = xyhcs(2:end,5);
 
         end%fcn
 
@@ -804,11 +804,14 @@
 
             for i = 1:builtin('numel', obj)
                 obji = obj(i);
+                if obji.numel() < 1
+                    continue
+                end
                 obji.x = flip(obji.x);
                 obji.y = flip(obji.y);
                 obji.head = flip(obji.head) + pi;
                 obji.curv = -flip(obji.curv);
-                obji.ArcLengths = [-flip(obji.ArcLengths(1:end-1)); 0] + obji.length();
+                obji.ArcLengths = cumsum(flip(diff(obji.arcLengths0())));
                 obj(i) = obji;
             end%for
 

SplinePath.m

@@ -77,6 +77,7 @@
             breaks = obj.Breaks;
             coefs = obj.Coefs;
             arcLen = obj.ArcLengths;
+            [~,P1] = obj.termPoints();
             breaks2 = obj2.Breaks;
             coefs2 = obj2.Coefs;
 
@@ -88,10 +89,9 @@
                 cat(3, zeros(2,n1,k2-k1), coefs), ...
                 cat(3, zeros(2,n2,k1-k2), coefs2));
 
-            [~,P1] = obj.termPoints();
-            P0 = obj2.termPoints();
-            ds = sqrt( sum((P0 - P1).^2) );
-            obj.ArcLengths = [arcLen; obj2.ArcLengths(2:end) + arcLen(end) + ds];
+            dP = obj2.termPoints() - P1;
+            ds = hypot(dP(1), dP(2));
+            obj.ArcLengths = [arcLen; obj2.ArcLengths + arcLen(end) + ds];
 
         end%fcn
 

resources/project/Root.type.Files/xUnitTests.type.File/PolygonPath.type.File/InterpTest.m.type.File.xml

@@ -0,0 +1,6 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<Info>
+    <Category UUID="FileClassCategory">
+        <Label UUID="test" />
+    </Category>
+</Info>

xUnitTests/PolygonPath/InterpTest.m

@@ -0,0 +1,23 @@
+classdef InterpTest < matlab.unittest.TestCase
+    
+    methods (Test)
+        function testInterpStraight(testCase)
+        % Test interpolation of a straight path.
+            
+            obj0 = PolygonPath.straight([0 0], [20 2]);
+            [tau0,tau1] = obj0.domain();
+            obj1 = obj0.interp(linspace(tau0, tau1, 100));
+            
+            % The terminal points must match
+            [exp0,exp1] = obj0.termPoints();
+            [act0,act1] = obj1.termPoints();
+            verifyEqual(testCase, act0, exp0);
+            verifyEqual(testCase, act1, exp1);
+            
+            % The length must match
+            verifyEqual(testCase, obj1.length(), obj0.length())
+            
+        end%fcn
+    end
+    
+end%class

xUnitTests/SplinePath/AppendTestSpline.m

@@ -3,25 +3,36 @@
     methods (Test)
         function testAppend(testCase)
 
-            % Join two "arbitrary" single segment paths with different
+            % Create two "arbitrary" single segment paths with different
             % polynomial degrees
             obj0 = SplinePath([0 1], reshape([1 2 1 0; 0 1 2 1], [2 1 4]));
             [~,P1]= obj0.termPoints();
             obj1 = SplinePath.straight(P1, P1 + [10; 5]);
+            
+            % This test assumes that the paths have no gap
+            assert(isequal(P1, obj1.termPoints()))
+            
+            % Join the two paths
             obj = obj0.append(obj1);
 
             % Evaluation of appended path must return the same values as
             % evaluation of the original paths
             tau = linspace(0, 1, 101);
+            
+            %  - First segment
             [xAct,yAct] = obj.eval(tau);
             [xExp,yExp] = obj0.eval(tau);
             verifyEqual(testCase, xAct, xExp);
             verifyEqual(testCase, yAct, yExp);
 
+            %  - Second segment
             [xAct,yAct] = obj.eval(tau + obj.Breaks(2));
             [xExp,yExp] = obj1.eval(tau);
             verifyEqual(testCase, xAct, xExp, 'AbsTol',2e-15);
             verifyEqual(testCase, yAct, yExp, 'AbsTol',2e-15);
+            
+            % The path lengths must match
+            verifyEqual(testCase, obj.length(), obj0.length() + obj1.length())
         end%fcn
     end