1// Copyright 2014 Google Inc. All rights reserved.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5//     You may obtain a copy of the License at
6//
7// http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12//     See the License for the specific language governing permissions and
13// limitations under the License.
14
15(function(scope, testing) {
16
17  function interpolate(from, to, f) {
18    if ((typeof from == 'number') && (typeof to == 'number')) {
19      return from * (1 - f) + to * f;
20    }
21    if ((typeof from == 'boolean') && (typeof to == 'boolean')) {
22      return f < 0.5 ? from : to;
23    }
24
25    WEB_ANIMATIONS_TESTING && console.assert(
26        Array.isArray(from) && Array.isArray(to),
27        'If interpolation arguments are not numbers or bools they must be arrays');
28
29    if (from.length == to.length) {
30      var r = [];
31      for (var i = 0; i < from.length; i++) {
32        r.push(interpolate(from[i], to[i], f));
33      }
34      return r;
35    }
36    throw 'Mismatched interpolation arguments ' + from + ':' + to;
37  }
38
39  scope.Interpolation = function(from, to, convertToString) {
40    return function(f) {
41      return convertToString(interpolate(from, to, f));
42    }
43  };
44
45  if (WEB_ANIMATIONS_TESTING) {
46    testing.interpolate = interpolate;
47  }
48
49})(webAnimations1, webAnimationsTesting);
50