angular2-signaturepad使用

詳細使用看這篇 https://blog.csdn.net/qq_29594393/article/details/76913495

npm地址： https://www.npmjs.com/package/signature_pad

遇到的問題

在網頁測試大小尺寸完好，移動端初始化的圖片很小

解決方案

let canvas = document.querySelector("canvas");
let ratio = Math.max(window.devicePixelRatio || 1, 1);
let signaWidth = this.platform.width()*0.92; //用的ionic里獲取設備寬度
canvas.width = signaWidth;
canvas.height = signaWidth;
canvas.getContext("2d").scale(ratio, ratio); //這步最關鍵調整比列
this.signaturePad.clear(); // otherwise isEmpty() might return incorrect value
this.signaturePad.fromDataURL(this.vehicleDamageImage)  //初始化的base64的圖片值