Upgrade to ExtJS 4.0.0 - Released 04/26/2011

[extjs.git] / src / fx / CubicBezier.js

diff --git a/src/fx/CubicBezier.js b/src/fx/CubicBezier.js
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+++ b/src/fx/CubicBezier.js
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+/**
+ * @class Ext.fx.CubicBezier
+ * @ignore
+ */
+Ext.define('Ext.fx.CubicBezier', {
+
+    /* Begin Definitions */
+
+    singleton: true,
+
+    /* End Definitions */
+
+    cubicBezierAtTime: function(t, p1x, p1y, p2x, p2y, duration) {
+        var cx = 3 * p1x,
+            bx = 3 * (p2x - p1x) - cx,
+            ax = 1 - cx - bx,
+            cy = 3 * p1y,
+            by = 3 * (p2y - p1y) - cy,
+            ay = 1 - cy - by;
+        function sampleCurveX(t) {
+            return ((ax * t + bx) * t + cx) * t;
+        }
+        function solve(x, epsilon) {
+            var t = solveCurveX(x, epsilon);
+            return ((ay * t + by) * t + cy) * t;
+        }
+        function solveCurveX(x, epsilon) {
+            var t0, t1, t2, x2, d2, i;
+            for (t2 = x, i = 0; i < 8; i++) {
+                x2 = sampleCurveX(t2) - x;
+                if (Math.abs(x2) < epsilon) {
+                    return t2;
+                }
+                d2 = (3 * ax * t2 + 2 * bx) * t2 + cx;
+                if (Math.abs(d2) < 1e-6) {
+                    break;
+                }
+                t2 = t2 - x2 / d2;
+            }
+            t0 = 0;
+            t1 = 1;
+            t2 = x;
+            if (t2 < t0) {
+                return t0;
+            }
+            if (t2 > t1) {
+                return t1;
+            }
+            while (t0 < t1) {
+                x2 = sampleCurveX(t2);
+                if (Math.abs(x2 - x) < epsilon) {
+                    return t2;
+                }
+                if (x > x2) {
+                    t0 = t2;
+                } else {
+                    t1 = t2;
+                }
+                t2 = (t1 - t0) / 2 + t0;
+            }
+            return t2;
+        }
+        return solve(t, 1 / (200 * duration));
+    },
+
+    cubicBezier: function(x1, y1, x2, y2) {
+        var fn = function(pos) {
+            return Ext.fx.CubicBezier.cubicBezierAtTime(pos, x1, y1, x2, y2, 1);
+        };
+        fn.toCSS3 = function() {
+            return 'cubic-bezier(' + [x1, y1, x2, y2].join(',') + ')';
+        };
+        fn.reverse = function() {
+            return Ext.fx.CubicBezier.cubicBezier(1 - x2, 1 - y2, 1 - x1, 1 - y1);
+        };
+        return fn;
+    }
+});
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