Circular arc approximation by cubic Bezier curve: Difference between revisions

Revision as of 12:26, 1 July 2012

@@ Line 6: / Line 6: @@
 var A = brd.create('glider', [1,0,c], {name:'A'});
 var B = brd.create('glider', [0,1,c], {name:'B'});
+var k = function(M, A, B) {
+    var ax = A.X()-M.X(),
+        ay = A.Y()-M.Y(),
+        bx = B.X()-M.X(),
+        by = B.Y()-M.Y(),
+        d, r;
+    r = M.Dist(A);
+    d = Math.sqrt((ax+bx)*(ax+bx) + (ay+by)*(ay+by));
+    if (Math.abs(by-ay)>JXG.Math.eps) {
+        return (ax+bx)*(r/d-0.5)*8.0/3.0/(by-ay);
+    } else {
+        return (ay+by)*(r/d-0.5)*8.0/3.0/(ax-bx);
+    }
+};
+var P1 = brd.create('point', [
+            function(){ return M.X()+A.X()-k(M,A,B)*(A.Y()-M.Y()); },
+            function(){ return M.Y()+A.Y()+k(M,A,B)*(A.X()-M.X()); }
+], {});
 </jsxgraph>