如何在触摸屏上生成平滑的贝塞尔曲线手势
<pre style="overflow-wrap: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 12px; line-height: 1.6; font-family: "YaHei Consolas Hybrid", Consolas, "Meiryo UI", "Malgun Gothic", "Segoe UI", "Trebuchet MS", Helvetica, monospace, monospace; box-sizing: border-box; margin-bottom: 1.5em; padding: 1em; overflow: auto; background: rgb(56, 69, 72); border-radius: 4px; border: 1px solid rgb(221, 221, 221); position: relative; color: rgb(209, 210, 210);"><code class="hljs csharp" style="overflow-wrap: normal; box-sizing: border-box; background: 0px 0px transparent; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; border-radius: 3px; border: 0px; word-break: normal; display: block; max-width: none; overflow-x: auto; overflow-y: initial; line-height: inherit;"><span class="hljs-comment" style="box-sizing: border-box; color: rgb(170, 170, 170); font-style: italic;"> 随机数生成函数</span><span class="hljs-function" style="box-sizing: border-box;">function <span class="hljs-title" style="box-sizing: border-box; color: rgb(97, 174, 238);">random</span>(<span class="hljs-params" style="box-sizing: border-box;">a, b</span>)</span> {
<span class="hljs-keyword" style="box-sizing: border-box; color: rgb(198, 120, 221);">return</span> rand.randNumber(a, b);
}
<span class="hljs-comment" style="box-sizing: border-box; color: rgb(170, 170, 170); font-style: italic;">/**
* @param time_ms {number} 执行时间 ms 例如 3000
* @param t {number} 间隔系数 0-1 间, 越小线条线条越圆润,计算量越大, 例如 0.005
* @param pt {number[][]} 控制点坐标的二维数组 例如 [,]
*/</span>
<span class="hljs-function" style="box-sizing: border-box;">function <span class="hljs-title" style="box-sizing: border-box; color: rgb(97, 174, 238);">bezier</span>(<span class="hljs-params" style="box-sizing: border-box;">time_ms, t, pt</span>)</span> {
<span class="hljs-keyword" style="box-sizing: border-box; color: rgb(198, 120, 221);">var</span> gesture1 = <span class="hljs-keyword" style="box-sizing: border-box; color: rgb(198, 120, 221);">new</span> path(); <span class="hljs-comment" style="box-sizing: border-box; color: rgb(170, 170, 170); font-style: italic;">// 创建一个手势对象</span>
gesture1.setStarTime(<span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">10</span>); <span class="hljs-comment" style="box-sizing: border-box; color: rgb(170, 170, 170); font-style: italic;">// 开始前延时</span>
<span class="hljs-keyword" style="box-sizing: border-box; color: rgb(198, 120, 221);">var</span> fps = <span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">1</span> / t;
<span class="hljs-keyword" style="box-sizing: border-box; color: rgb(198, 120, 221);">for</span> (<span class="hljs-keyword" style="box-sizing: border-box; color: rgb(198, 120, 221);">let</span> i = <span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">0</span>; i <= fps; i++) {
<span class="hljs-keyword" style="box-sizing: border-box; color: rgb(198, 120, 221);">let</span> copyArr = Array.<span class="hljs-keyword" style="box-sizing: border-box; color: rgb(198, 120, 221);">from</span>(pt, row => row.slice()); <span class="hljs-comment" style="box-sizing: border-box; color: rgb(170, 170, 170); font-style: italic;">// 拷贝一份 js的数组是引用传递</span>
<span class="hljs-keyword" style="box-sizing: border-box; color: rgb(198, 120, 221);">var</span> xy = calculateBezier(i * t, copyArr);
gesture1.addPoint(xy[<span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">0</span>], xy[<span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">1</span>]);
}
gesture1.setDurTime(time_ms); <span class="hljs-comment" style="box-sizing: border-box; color: rgb(170, 170, 170); font-style: italic;">// 完成时间</span>
auto.dispatchGesture(); <span class="hljs-comment" style="box-sizing: border-box; color: rgb(170, 170, 170); font-style: italic;">// 执行手势操作</span>
}
<span class="hljs-comment" style="box-sizing: border-box; color: rgb(170, 170, 170); font-style: italic;">/**
* @param t {number} 0 ~ 1的时间
* @param point2Fs {number[][]} 贝塞尔点集合
* @return {number[]} 返回当前时间下的贝塞尔点
*/</span>
<span class="hljs-function" style="box-sizing: border-box;">function <span class="hljs-title" style="box-sizing: border-box; color: rgb(97, 174, 238);">calculateBezier</span>(<span class="hljs-params" style="box-sizing: border-box;">t, point2Fs</span>)</span> {
<span class="hljs-keyword" style="box-sizing: border-box; color: rgb(198, 120, 221);">let</span> len = point2Fs.length;
<span class="hljs-keyword" style="box-sizing: border-box; color: rgb(198, 120, 221);">for</span> (<span class="hljs-keyword" style="box-sizing: border-box; color: rgb(198, 120, 221);">let</span> i = len - <span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">1</span>; i > <span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">0</span>; i--) {
<span class="hljs-keyword" style="box-sizing: border-box; color: rgb(198, 120, 221);">for</span> (<span class="hljs-keyword" style="box-sizing: border-box; color: rgb(198, 120, 221);">let</span> j = <span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">0</span>; j < i; j++) {
point2Fs[<span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">0</span>] = point2Fs[<span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">0</span>] + (point2Fs[<span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">0</span>] - point2Fs[<span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">0</span>]) * t;
point2Fs[<span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">1</span>] = point2Fs[<span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">1</span>] + (point2Fs[<span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">1</span>] - point2Fs[<span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">1</span>]) * t;
}
}
<span class="hljs-keyword" style="box-sizing: border-box; color: rgb(198, 120, 221);">return</span> [<span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">0</span>]), parseInt(point2Fs[<span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">0</span>][<span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">1</span>])];
}
<span class="hljs-comment" style="box-sizing: border-box; color: rgb(170, 170, 170); font-style: italic;">// 控制点</span>
<span class="hljs-keyword" style="box-sizing: border-box; color: rgb(198, 120, 221);">var</span> CtrlPt1 = [
[<span class="hljs-meta" style="box-sizing: border-box; color: rgb(97, 174, 238);">167, 625</span>], <span class="hljs-comment" style="box-sizing: border-box; color: rgb(170, 170, 170); font-style: italic;">// 起点1</span>
[<span class="hljs-meta" style="box-sizing: border-box; color: rgb(97, 174, 238);">200, 200</span>],
[<span class="hljs-meta" style="box-sizing: border-box; color: rgb(97, 174, 238);">500, 500</span>],
[<span class="hljs-meta" style="box-sizing: border-box; color: rgb(97, 174, 238);">300, 100</span>]
];
<span class="hljs-keyword" style="box-sizing: border-box; color: rgb(198, 120, 221);">var</span> CtrlPt2 = [
[<span class="hljs-meta" style="box-sizing: border-box; color: rgb(97, 174, 238);">309, 833</span>], <span class="hljs-comment" style="box-sizing: border-box; color: rgb(170, 170, 170); font-style: italic;">// 起点2</span>
[<span class="hljs-meta" style="box-sizing: border-box; color: rgb(97, 174, 238);">500, 700</span>],
[<span class="hljs-meta" style="box-sizing: border-box; color: rgb(97, 174, 238);">600, 600</span>],
[<span class="hljs-meta" style="box-sizing: border-box; color: rgb(97, 174, 238);">500, 300</span>]
];
<span class="hljs-keyword" style="box-sizing: border-box; color: rgb(198, 120, 221);">var</span> CtrlPt3 = [
[<span class="hljs-meta" style="box-sizing: border-box; color: rgb(97, 174, 238);">151, 892</span>], <span class="hljs-comment" style="box-sizing: border-box; color: rgb(170, 170, 170); font-style: italic;">// 起点3</span>
[<span class="hljs-meta" style="box-sizing: border-box; color: rgb(97, 174, 238);">300, 880</span>], <span class="hljs-comment" style="box-sizing: border-box; color: rgb(170, 170, 170); font-style: italic;">// 引入Y坐标的小变化</span>
[<span class="hljs-meta" style="box-sizing: border-box; color: rgb(97, 174, 238);">450, 895</span>], <span class="hljs-comment" style="box-sizing: border-box; color: rgb(170, 170, 170); font-style: italic;">// 引入Y坐标的小变化</span>
[<span class="hljs-meta" style="box-sizing: border-box; color: rgb(97, 174, 238);">600, 885</span>]<span class="hljs-comment" style="box-sizing: border-box; color: rgb(170, 170, 170); font-style: italic;">// 引入Y坐标的小变化</span>
];
<span class="hljs-comment" style="box-sizing: border-box; color: rgb(170, 170, 170); font-style: italic;">// 执行贝塞尔手势</span>
bezier(<span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">4000</span>, <span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">0.005</span>, CtrlPt1);
bezier(<span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">4000</span>, <span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">0.005</span>, CtrlPt2);
bezier(<span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">4000</span>, <span class="hljs-number" style="box-sizing: border-box; color: rgb(209, 154, 102);">0.005</span>, CtrlPt3);
</code></pre><h3 id="h3--code-bezier-time_ms-t-pt-code-" style="margin-top: 1em; margin-bottom: 1.5em; box-sizing: border-box; position: relative; line-height: 1.75; color: rgb(51, 51, 51); font-family: "Microsoft YaHei", Helvetica, "Meiryo UI", "Malgun Gothic", "Segoe UI", "Trebuchet MS", Monaco, monospace, Tahoma, STXihei, 华文细黑, STHeiti, "Helvetica Neue", "Droid Sans", "wenquanyi micro hei", FreeSans, Arimo, Arial, SimSun, 宋体, Heiti, 黑体, sans-serif; font-size: 1.25em !important;"><a name="<code>bezier(time_ms, t, pt)</code> 函数" class="reference-link" style="color: rgb(65, 131, 196); transition: color 0.08s ease-out 0s; box-sizing: border-box; background: 0px 0px;"></a><code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; font-size: 14px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">bezier(time_ms, t, pt)</code> 函数</h3><div></div><div><br></div><p style="margin-bottom: 1.5em; box-sizing: border-box; color: rgb(51, 51, 51); font-family: "Microsoft YaHei", Helvetica, "Meiryo UI", "Malgun Gothic", "Segoe UI", "Trebuchet MS", Monaco, monospace, Tahoma, STXihei, 华文细黑, STHeiti, "Helvetica Neue", "Droid Sans", "wenquanyi micro hei", FreeSans, Arimo, Arial, SimSun, 宋体, Heiti, 黑体, sans-serif;">这个函数用于生成并执行一个贝塞尔曲线手势。具体参数解释如下：</p><ol style="margin-bottom: 1.5em; padding-left: 2em; box-sizing: border-box; color: rgb(51, 51, 51); font-family: "Microsoft YaHei", Helvetica, "Meiryo UI", "Malgun Gothic", "Segoe UI", "Trebuchet MS", Monaco, monospace, Tahoma, STXihei, 华文细黑, STHeiti, "Helvetica Neue", "Droid Sans", "wenquanyi micro hei", FreeSans, Arimo, Arial, SimSun, 宋体, Heiti, 黑体, sans-serif;"><li style="box-sizing: border-box;"><p style="margin-top: 16px; margin-bottom: 1.5em; box-sizing: border-box;"><span style="box-sizing: border-box; font-weight: 700;"><code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; margin-right: 4px; margin-left: 5px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">time_ms</code></span>：</p><ul style="margin-left: 14px; padding-left: 2em; box-sizing: border-box;"><li style="list-style: disc; box-sizing: border-box;"><span style="box-sizing: border-box; font-weight: 700;">作用</span>：定义手势从开始到结束的总时间，单位是毫秒。</li><li style="list-style: disc; box-sizing: border-box;"><span style="box-sizing: border-box; font-weight: 700;">示例</span>：<code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">bezier(4000, 0.005, CtrlPt1);</code> 表示整个手势将在4000毫秒（4秒）内完成。</li></ul></li><li style="box-sizing: border-box;"><p style="margin-top: 16px; margin-bottom: 1.5em; box-sizing: border-box;"><span style="box-sizing: border-box; font-weight: 700;"><code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; margin-right: 4px; margin-left: 5px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">t</code></span>：</p><ul style="margin-left: 14px; padding-left: 2em; box-sizing: border-box;"><li style="list-style: disc; box-sizing: border-box;"><span style="box-sizing: border-box; font-weight: 700;">作用</span>：定义间隔系数，用于控制贝塞尔曲线的计算精度和线条的圆润度。<code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">t</code> 的取值范围是0到1之间。</li><li style="list-style: disc; box-sizing: border-box;"><span style="box-sizing: border-box; font-weight: 700;">精度与圆润度</span>：较小的 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">t</code> 值意味着计算的间隔更小，生成的曲线更圆润，但计算量也会相应增加。较大的 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">t</code> 值则表示计算间隔更大，曲线可能会显得更折线化，计算量较少。</li><li style="list-style: disc; box-sizing: border-box;"><span style="box-sizing: border-box; font-weight: 700;">示例</span>：<code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">bezier(4000, 0.005, CtrlPt1);</code> 中的 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">t</code> 为0.005，表示每0.005的时间单位计算一次贝塞尔曲线上的点。</li></ul></li><li style="box-sizing: border-box;"><p style="margin-top: 16px; margin-bottom: 1.5em; box-sizing: border-box;"><span style="box-sizing: border-box; font-weight: 700;"><code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; margin-right: 4px; margin-left: 5px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">pt</code></span>：</p><ul style="margin-left: 14px; padding-left: 2em; box-sizing: border-box;"><li style="list-style: disc; box-sizing: border-box;"><span style="box-sizing: border-box; font-weight: 700;">作用</span>：定义贝塞尔曲线的控制点坐标。控制点决定了贝塞尔曲线的形状。起点和终点是曲线的两端，而中间的控制点决定了曲线如何弯曲。</li><li style="list-style: disc; box-sizing: border-box;"><span style="box-sizing: border-box; font-weight: 700;">格式</span>：<code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">pt</code> 是一个二维数组，其中每个子数组包含两个数字，分别表示控制点的X坐标和Y坐标。</li><li style="list-style: disc; box-sizing: border-box;"><span style="box-sizing: border-box; font-weight: 700;">示例</span>：<ul style="margin-left: 14px; padding-left: 2em; box-sizing: border-box;"><li style="list-style: disc; box-sizing: border-box;"><code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">CtrlPt1</code> 定义了起点 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);"></code>，两个控制点 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);"></code> 和 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);"></code>，以及终点 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);"></code>。</li><li style="list-style: disc; box-sizing: border-box;"><code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">CtrlPt2</code> 定义了起点 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);"></code>，两个控制点 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);"></code> 和 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);"></code>，以及终点 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);"></code>。</li><li style="list-style: disc; box-sizing: border-box;"><code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">CtrlPt3</code> 定义了起点 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);"></code>，两个控制点 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);"></code> 和 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);"></code>，以及终点 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);"></code>。</li></ul></li></ul></li></ol><h3 id="h3--code-calculatebezier-t-point2fs-code-" style="margin-top: 1em; margin-bottom: 1.5em; box-sizing: border-box; position: relative; line-height: 1.75; color: rgb(51, 51, 51); font-family: "Microsoft YaHei", Helvetica, "Meiryo UI", "Malgun Gothic", "Segoe UI", "Trebuchet MS", Monaco, monospace, Tahoma, STXihei, 华文细黑, STHeiti, "Helvetica Neue", "Droid Sans", "wenquanyi micro hei", FreeSans, Arimo, Arial, SimSun, 宋体, Heiti, 黑体, sans-serif; font-size: 1.25em !important;"><a name="<code>calculateBezier(t, point2Fs)</code> 函数" class="reference-link" style="color: rgb(65, 131, 196); transition: color 0.08s ease-out 0s; box-sizing: border-box; background: 0px 0px;"></a><code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; font-size: 14px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">calculateBezier(t, point2Fs)</code> 函数</h3><p style="margin-bottom: 1.5em; box-sizing: border-box; color: rgb(51, 51, 51); font-family: "Microsoft YaHei", Helvetica, "Meiryo UI", "Malgun Gothic", "Segoe UI", "Trebuchet MS", Monaco, monospace, Tahoma, STXihei, 华文细黑, STHeiti, "Helvetica Neue", "Droid Sans", "wenquanyi micro hei", FreeSans, Arimo, Arial, SimSun, 宋体, Heiti, 黑体, sans-serif;">这个函数用于计算贝塞尔曲线在某个时间点 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; margin-right: 4px; margin-left: 5px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">t</code> 上的坐标。具体参数解释如下：</p><ol style="margin-bottom: 1.5em; padding-left: 2em; box-sizing: border-box; color: rgb(51, 51, 51); font-family: "Microsoft YaHei", Helvetica, "Meiryo UI", "Malgun Gothic", "Segoe UI", "Trebuchet MS", Monaco, monospace, Tahoma, STXihei, 华文细黑, STHeiti, "Helvetica Neue", "Droid Sans", "wenquanyi micro hei", FreeSans, Arimo, Arial, SimSun, 宋体, Heiti, 黑体, sans-serif;"><li style="box-sizing: border-box;"><p style="margin-top: 16px; margin-bottom: 1.5em; box-sizing: border-box;"><span style="box-sizing: border-box; font-weight: 700;"><code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; margin-right: 4px; margin-left: 5px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">t</code></span>：</p><ul style="margin-left: 14px; padding-left: 2em; box-sizing: border-box;"><li style="list-style: disc; box-sizing: border-box;"><span style="box-sizing: border-box; font-weight: 700;">作用</span>：表示时间参数，取值范围是0到1之间。<code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">t=0</code> 对应曲线的起点，<code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">t=1</code> 对应曲线的终点。</li><li style="list-style: disc; box-sizing: border-box;"><span style="box-sizing: border-box; font-weight: 700;">计算过程</span>：通过递归地插值计算，最终得到 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">t</code> 时刻的曲线坐标。</li></ul></li><li style="box-sizing: border-box;"><p style="margin-top: 16px; margin-bottom: 1.5em; box-sizing: border-box;"><span style="box-sizing: border-box; font-weight: 700;"><code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; margin-right: 4px; margin-left: 5px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">point2Fs</code></span>：</p><ul style="margin-left: 14px; padding-left: 2em; box-sizing: border-box;"><li style="list-style: disc; box-sizing: border-box;"><span style="box-sizing: border-box; font-weight: 700;">作用</span>：包含贝塞尔曲线的控制点坐标。</li><li style="list-style: disc; box-sizing: border-box;"><span style="box-sizing: border-box; font-weight: 700;">格式</span>：二维数组，每个子数组包含两个数字，分别表示控制点的X坐标和Y坐标。</li></ul></li></ol><h3 id="h3-u8BA1u7B97u8D1Du585Eu5C14u66F2u7EBFu7684u8BE6u7EC6u8FC7u7A0B" style="margin-top: 1em; margin-bottom: 1.5em; box-sizing: border-box; position: relative; line-height: 1.75; color: rgb(51, 51, 51); font-family: "Microsoft YaHei", Helvetica, "Meiryo UI", "Malgun Gothic", "Segoe UI", "Trebuchet MS", Monaco, monospace, Tahoma, STXihei, 华文细黑, STHeiti, "Helvetica Neue", "Droid Sans", "wenquanyi micro hei", FreeSans, Arimo, Arial, SimSun, 宋体, Heiti, 黑体, sans-serif; font-size: 1.25em !important;"><a name="计算贝塞尔曲线的详细过程" class="reference-link" style="color: rgb(65, 131, 196); transition: color 0.08s ease-out 0s; box-sizing: border-box; background: 0px 0px;"></a>计算贝塞尔曲线的详细过程</h3><p style="margin-bottom: 1.5em; box-sizing: border-box; color: rgb(51, 51, 51); font-family: "Microsoft YaHei", Helvetica, "Meiryo UI", "Malgun Gothic", "Segoe UI", "Trebuchet MS", Monaco, monospace, Tahoma, STXihei, 华文细黑, STHeiti, "Helvetica Neue", "Droid Sans", "wenquanyi micro hei", FreeSans, Arimo, Arial, SimSun, 宋体, Heiti, 黑体, sans-serif;">贝塞尔曲线的计算通常使用递归的插值方法。在 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; margin-right: 4px; margin-left: 5px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">calculateBezier</code> 函数中，具体步骤如下：</p><ol style="margin-bottom: 1.5em; padding-left: 2em; box-sizing: border-box; color: rgb(51, 51, 51); font-family: "Microsoft YaHei", Helvetica, "Meiryo UI", "Malgun Gothic", "Segoe UI", "Trebuchet MS", Monaco, monospace, Tahoma, STXihei, 华文细黑, STHeiti, "Helvetica Neue", "Droid Sans", "wenquanyi micro hei", FreeSans, Arimo, Arial, SimSun, 宋体, Heiti, 黑体, sans-serif;"><li style="box-sizing: border-box;"><p style="margin-top: 16px; margin-bottom: 1.5em; box-sizing: border-box;"><span style="box-sizing: border-box; font-weight: 700;">拷贝控制点数组</span>：</p><ul style="margin-left: 14px; padding-left: 2em; box-sizing: border-box;"><li style="list-style: disc; box-sizing: border-box;">由于 JavaScript 中数组是引用传递的，为了避免修改原始控制点数组，首先需要拷贝一份 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">point2Fs</code>。</li></ul></li><li style="box-sizing: border-box;"><p style="margin-top: 16px; margin-bottom: 1.5em; box-sizing: border-box;"><span style="box-sizing: border-box; font-weight: 700;">递归插值计算</span>：</p><ul style="margin-left: 14px; padding-left: 2em; box-sizing: border-box;"><li style="list-style: disc; box-sizing: border-box;">对于每个控制点，通过线性插值计算新的点，直到只剩下一个点为止。</li><li style="list-style: disc; box-sizing: border-box;">具体公式为：<code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">point2Fs = point2Fs + (point2Fs - point2Fs) * t;</code><ul style="margin-left: 14px; padding-left: 2em; box-sizing: border-box;"><li style="list-style: disc; box-sizing: border-box;">这里的 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">t</code> 是当前时间参数，<code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">point2Fs</code> 和 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">point2Fs</code> 是相邻控制点的X坐标。</li><li style="list-style: disc; box-sizing: border-box;">通过这个公式计算新的X坐标。</li></ul></li><li style="list-style: disc; box-sizing: border-box;">同样地，计算新的Y坐标：<code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">point2Fs = point2Fs + (point2Fs - point2Fs) * t;</code></li></ul></li><li style="box-sizing: border-box;"><p style="margin-top: 16px; margin-bottom: 1.5em; box-sizing: border-box;"><span style="box-sizing: border-box; font-weight: 700;">返回结果</span>：</p><ul style="margin-left: 14px; padding-left: 2em; box-sizing: border-box;"><li style="list-style: disc; box-sizing: border-box;">最终，<code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">point2Fs</code> 将包含贝塞尔曲线在 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">t</code> 时间点的坐标。</li><li style="list-style: disc; box-sizing: border-box;">返回这个坐标 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">), parseInt(point2Fs)]</code>，其中 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">parseInt</code> 用于将坐标转换为整数。</li></ul></li></ol><h3 id="h3-u6267u884Cu8D1Du585Eu5C14u624Bu52BF" style="margin-top: 1em; margin-bottom: 1.5em; box-sizing: border-box; position: relative; line-height: 1.75; color: rgb(51, 51, 51); font-family: "Microsoft YaHei", Helvetica, "Meiryo UI", "Malgun Gothic", "Segoe UI", "Trebuchet MS", Monaco, monospace, Tahoma, STXihei, 华文细黑, STHeiti, "Helvetica Neue", "Droid Sans", "wenquanyi micro hei", FreeSans, Arimo, Arial, SimSun, 宋体, Heiti, 黑体, sans-serif; font-size: 1.25em !important;"><a name="执行贝塞尔手势" class="reference-link" style="color: rgb(65, 131, 196); transition: color 0.08s ease-out 0s; box-sizing: border-box; background: 0px 0px;"></a>执行贝塞尔手势</h3><p style="box-sizing: border-box; color: rgb(51, 51, 51); font-family: "Microsoft YaHei", Helvetica, "Meiryo UI", "Malgun Gothic", "Segoe UI", "Trebuchet MS", Monaco, monospace, Tahoma, STXihei, 华文细黑, STHeiti, "Helvetica Neue", "Droid Sans", "wenquanyi micro hei", FreeSans, Arimo, Arial, SimSun, 宋体, Heiti, 黑体, sans-serif;">在 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; margin-right: 4px; margin-left: 5px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">bezier</code> 函数中，通过循环调用 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; margin-right: 4px; margin-left: 5px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">calculateBezier</code> 函数，生成从起点到终点的一系列点，并将这些点添加到 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; margin-right: 4px; margin-left: 5px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">gesture1</code> 对象中，最后通过 <code style="box-sizing: border-box; font-family: Consolas, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace; padding: 3px; margin-right: 4px; margin-left: 5px; background: rgb(249, 249, 249); border-radius: 3px; border: 1px solid rgb(221, 221, 221); color: rgb(64, 158, 255);">auto.dispatchGesture();</code> 执行这个手势操作。</p><p></p>
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