微信小程序实现分享朋友圈的图片功能示例

<view class="canvas-box">
    <canvas canvas-id="myCanvas" style="width:100%;height:{{windowHeight}}px;"></canvas>
</view>
<button bindtap='startDraw'>分享朋友圈</button>

.canvas-box{
  width: 100%;
  position: fixed;
  left: 0;
  : 999999rpx;
}

startDraw:function(){
 const ctx = wx.createCanvasContext('myCanvas');
  let windowWidth = wx.getSystemInfoSync().windowWidth;
  let windowHeight = wx.getSystemInfoSync().windowHeight;
  let _this=this;
  this.setData({
   scale: 1.6
  });
  ctx.setFillStyle('#333');
  ctx.fillRect(0, 0, windowWidth, 100);
  ctx.setFontSize(20);
  ctx.setFillStyle('#fff');
  ctx.fillText('开始绘制图片', 30, 50);
  ctx.setFillStyle('#FFF');
  ctx.fillRect(0, 70, windowWidth, 600);
  ctx.setFillStyle('#666');
  ctx.setFontSize(19);
  ctx.fillText('我是标题',100, 140);
  ctx.setFontSize(20);
  ctx.fillText('微信小程序文本部分',20 , 170);
  ctx.draw()
}

wx.canvasToTempFilePath({
   x: 0,
   y: 0,
   width: windowWidth,
   height: windowHeight,
   destWidth: windowWidth,
   destHeight: windowHeight,
   canvasId: 'myCanvas',
   suess: function (res1) {
    console.log('朋友圈分享图生成成功:' + res1.tempFilePath);
   }
});