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<a name="Tweening"></a>
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<p>
Previous: <a href="Easings.html#Easings" accesskey="p" rel="prev">Easings</a>, Up: <a href="Tweens.html#Tweens" accesskey="u" rel="up">Tweens</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
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<a name="Tweening-1"></a>
<h4 class="subsubsection">4.2.4.2 Tweening</h4>
<p>The <code>tween</code> procedure creates new procedures to be used for
animation. For example, the code below creates a tween procedure that
linearly interpolates (0, 0) to (10, 10) over the course of ten ticks.
</p>
<div class="example">
<pre class="example">(define t (tween vlerp ease-linear (vector2 0 0) (vector2 10 0) 10))
(t 5) ;; => (vector2 5 5)
</pre></div>
<dl>
<dt><a name="index-tween"></a>Scheme Procedure: <strong>tween</strong> <em><var>interpolator</var> <var>ease</var> <var>start</var> <var>end</var> <var>duration</var></em></dt>
<dd><p>Return a procedure that interpolates from <var>start</var> to <var>end</var> in
<var>duration</var> ticks. The value returned for a given time is
determined by applying <var>ease</var> with the time ratio to acquire an
<var>alpha</var> value, and then applying <var>interpolator</var> with
<var>start</var>, <var>end</var>, and <var>alpha</var>. <var>alpha</var> is a rational
number in the range [0, 1].
</p></dd></dl>
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