92 lines
2.6 KiB
JavaScript
92 lines
2.6 KiB
JavaScript
/**
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* @file quadraticBezier.js
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* @author mengke01
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* @date
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* @description
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* 三次贝塞尔转二次
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*/
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define(
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function(require) {
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var bezierCubic2Q2 = require('math/bezierCubic2Q2');
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var entry = {
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/**
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* 初始化
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*/
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init: function() {
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var canvas = $('#canvas').get(0);
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var ctx = canvas.getContext('2d');
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var width = canvas.offsetWidth;
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var height = canvas.offsetHeight;
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var points =[{"x":167,"y":449},{"x":233,"y":331},{"x":431,"y":332},{"x":481,"y":417}];
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$(points).each(function(index, item) {
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$('[data-index="'+index+'"]').css({
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left: points[index].x,
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top: points[index].y
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})
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});
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var point;
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$('.point').on('mousedown', function(e) {
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point = $(this);
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});
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$(document.body).on('mousemove', onMove);
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$(document.body).on('mouseup', function(e) {
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onMove.call(this, e);
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point = null;
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});
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function onMove(e) {
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var px = e.pageX;
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var py = e.pageY;
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if(point) {
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point.css({
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left: px,
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top: py
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});
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var p = points[+point.attr('data-index')];
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p.x = px;
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p.y = py;
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draw();
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}
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}
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function draw() {
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ctx.clearRect(0, 0, width, height);
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//绘制2次贝塞尔曲线
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ctx.beginPath();
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ctx.strokeStyle='red';
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ctx.moveTo(points[0].x, points[0].y);
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ctx.bezierCurveTo(points[1].x,points[1].y,points[2].x,points[2].y,points[3].x,points[3].y);
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ctx.stroke();
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ctx.beginPath();
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ctx.strokeStyle='blue';
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bezierCubic2Q2.apply(null, points).forEach(function(bezier) {
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ctx.moveTo(bezier[0].x, bezier[0].y);
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ctx.quadraticCurveTo(bezier[1].x, bezier[1].y, bezier[2].x, bezier[2].y);
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});
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ctx.stroke();
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}
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draw();
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}
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};
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entry.init();
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return entry;
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}
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); |