基于canvas 的网页签名组件，支持毛笔字模式和普通模式，或导出图片。
Signature on website base on html5 canvas, it provide handwritting simulation feature and pen mode.
yarn install
yarn start
open http://localhost:8080 in browser.
base
import HandWrite from 'canvas-signature'
const canvas = document.querySelector('#canvas');
const instance = new HandWrite(canvas[, options]);
const options = {
paintColor: '#f00',
backgroundColor: 'rgba(0, 0, 0, 0)',
isHandWrittingModel: true,
maxWidth: 15,
minWidth: 5,
writeSpeed: 30, // 书写速度，关联控制速度与笔画粗细的阈值
beforeWrite: ()=>{},
onWritting: ()=>{}, // 谨慎使用，可能造成性能问题
afterWrite: ()=>{},
}
handWrittingModel
instance.handWrittingModel();
linearModel
instance.linearModel();
getImgData
instance.getImgData('png'); // default: png
downloadImage
instance.downloadImage('jpeg'); // default: png
clear Canvas
instance.clear();