shanxia2.0/miniprogram/utils/makeQrTempFile.js

import UQRCode from 'uqrcodejs'

/**
 * 在组件内隐藏 canvas 上绘制二维码，导出临时文件路径供 <image> 展示。
 * @param {object} opts
 * @param {string} opts.text 二维码内容（出入库单 id）
 * @param {string} opts.canvasId canvas-id
 * @param {object} opts.componentInstance 组件实例（getCurrentInstance().proxy）
 * @param {number} [opts.size=200]
 * @returns {Promise<string>} tempFilePath
 */
export function makeQrTempFile({ text, canvasId, componentInstance, size = 200 }) {
  const content = String(text || '').trim()
  if (!content) {
    return Promise.reject(new Error('二维码内容为空'))
  }
  if (!componentInstance) {
    return Promise.reject(new Error('缺少组件实例'))
  }

  return new Promise((resolve, reject) => {
    try {
      const qr = new UQRCode()
      qr.data = content
      qr.size = size
      qr.margin = 10
      qr.make()
      const ctx = uni.createCanvasContext(canvasId, componentInstance)
      qr.canvasContext = ctx
      qr.drawCanvas()
      // drawCanvas 内部会 ctx.draw；稍延迟再导出
      setTimeout(() => {
        uni.canvasToTempFilePath(
          {
            canvasId,
            width: size,
            height: size,
            destWidth: size,
            destHeight: size,
            success: (res) => {
              if (res.tempFilePath) resolve(res.tempFilePath)
              else reject(new Error('二维码导出失败'))
            },
            fail: (err) => reject(err || new Error('二维码导出失败'))
          },
          componentInstance
        )
      }, 120)
    } catch (e) {
      reject(e)
    }
  })
}