【HarmonyOS NEXT】使用Canvas实现手写签名

1. 封装SignatureBoard组件

import {
    image } from '@kit.ImageKit';

@Component
export struct SignatureBoard {
   
  private boardWidth: number = 300
  private boardHeight: number = 200
  private lastX: number = 0
  private lastY: number = 0
  private isDown: Boolean = false
  private panOption: PanGestureOptions = new PanGestureOptions({
    direction: PanDirection.All, distance: 1 })
  private settings: RenderingContextSettings = new RenderingContextSettings(true)
  private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings)
  onConfirm: (pixelMap: image.PixelMap) => void = () => {
   
  }

  draw(startX: number, startY: number, endX: number, endY: number) {
   
    // 起点
    this.context.moveTo