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Removed toquad.js

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be5invis 2015-10-13 19:41:22 +08:00
parent 9e6bb1aac0
commit f86faba3a9
1 changed files with 0 additions and 95 deletions
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95
support/toquad.js
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@ -1,95 +0,0 @@
function toQuad(p1, c1, c2, p2) {
// Quad control point is (3*c2 - p2 + 3*c1 - p1)/4
var x = (3 * c2.x - p2.x + 3 * c1.x - p1.x) / 4;
var y = (3 * c2.y - p2.y + 3 * c1.y - p1.y) / 4;
if(Math.abs(c1.x - p1.x) < 0.25) x = p1.x;
if(Math.abs(c2.x - p2.x) < 0.25) x = p2.x;
if(Math.abs(c1.y - p1.y) < 0.25) y = p1.y;
if(Math.abs(c2.y - p2.y) < 0.25) y = p2.y;
return [
p1,
{
x: x,
y: y
},
p2
];
}
/**
* 三次贝塞尔转二次贝塞尔
*
* @param {Object} p1 开始点
* @param {Object} c1 控制点1
* @param {Object} c2 控制点2
* @param {Object} p2 结束点
* @return {Array} 二次贝塞尔控制点
*/
function bezierCubic2Q2(p1, c1, c2, p2, level) {
level = level || 0;
// 判断极端情况，控制点和起止点一样
if (p1.x === c1.x && p1.y === c1.y && c2.x === p2.x && c2.y === p2.y) {
return [
[
p1,
{
x: (p1.x + p2.x) / 2,
y: (p1.y + p2.y) / 2
},
p2
]
];
}
var mx = p2.x - 3 * c2.x + 3 * c1.x - p1.x;
var my = p2.y - 3 * c2.y + 3 * c1.y - p1.y;
// control points near
if (mx * mx + my * my <= 4 || level > 5) {
return [
toQuad(p1, c1, c2, p2)
];
}
// Split to 2 qubic beziers by midpoints
// (p2 + 3*c2 + 3*c1 + p1)/8
var mp = {
x: (p2.x + 3 * c2.x + 3 * c1.x + p1.x) / 8,
y: (p2.y + 3 * c2.y + 3 * c1.y + p1.y) / 8
};
return bezierCubic2Q2(
p1,
{
x: (p1.x + c1.x) / 2,
y: (p1.y + c1.y) / 2
},
{
x: (p1.x + 2 * c1.x + c2.x) / 4,
y: (p1.y + 2 * c1.y + c2.y) / 4
},
mp,
level + 1
).concat(bezierCubic2Q2(
mp,
{
x: (p2.x + c1.x + 2 * c2.x) / 4,
y: (p2.y + c1.y + 2 * c2.y) / 4
},
{
x: (p2.x + c2.x) / 2,
y: (p2.y + c2.y) / 2
},
p2,
level + 1
))
}
module.exports = bezierCubic2Q2;