wx.canvasToTempFilePath不走成功函数
发布于 6 年前 作者 mjia 15678 次浏览 来自 问答
// pages/canvas/canvasText.js
Page({
  data: {
    x: 0,
    y: 0,
    hidden: true
  },
  onLoad:function(){
    const ctx = wx.createCanvasContext('myCanvas')
 
    // Create linear gradient
    const grd = ctx.createLinearGradient(0, 0, 10, 80)
    grd.addColorStop(0, 'red')
    grd.addColorStop(1, 'white')
 
    // Fill with gradient
    ctx.setFillStyle(grd)
    ctx.fillRect(10, 10, 150, 80)
    ctx.draw()
    wx.canvasToTempFilePath({
      x: 10,
      y: 10,
      width: 50,
      height: 50,
      destWidth: 100,
      destHeight: 100,
      canvasId: 'myCanvas',
      success: function (res) {
        console.log('res',res.tempFilePath)
      },
      fail:function(err){
        console.log('err',err)
      },
      complete:function(data){
        console.log('data', data)
      }
    })
  },
  start: function (e) {
    this.setData({
      hidden: false,
      x: e.touches[0].x,
      y: e.touches[0].y
    })
  },
  move: function (e) {
    this.setData({
      x: e.touches[0].x,
      y: e.touches[0].y
    })
  },
  end: function (e) {
    this.setData({
      hidden: true
    })
  }
})

打印出来是err：canvas为空，是这种简单的绘图不支持转成图片输出么？求大佬解答

<canvas canvas-id="myCanvas"
  style="margin: 5px; border:1px solid #d3d3d3;"
  bindtouchstart="start"
  bindtouchmove="move"
  bindtouchend="end"/>
<view hidden="{{hidden}}">
  Coordinates: ({{x}}, {{y}})
</view>
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