微信小程序生成二维码案例
时间: 2023-07-06 07:25:06 浏览: 78
以下是一个基于微信小程序的生成二维码的代码示例:
WXML代码:
```
<view class="container">
<canvas canvas-id="qrcode"></canvas>
</view>
```
JS代码:
```
Page({
data: {
qrcode: ''
},
onLoad: function() {
this.createQRCode('https://www.example.com');
},
createQRCode: function(url) {
var that = this;
wx.request({
url: 'https://api.weixin.qq.com/wxa/getwxacode',
method: 'POST',
responseType: 'arraybuffer',
data: {
path: url,
width: 280
},
success: function(res) {
var base64 = wx.arrayBufferToBase64(res.data);
var qrcode = 'data:image/png;base64,' + base64;
that.setData({
qrcode: qrcode
}, function() {
that.drawQRCode();
})
}
})
},
drawQRCode: function() {
var that = this;
var qrcode = this.data.qrcode;
wx.createSelectorQuery().select('#qrcode').fields({
node: true,
size: true
}).exec(function(res) {
var canvas = res[0].node;
var ctx = canvas.getContext('2d');
var dpr = wx.getSystemInfoSync().pixelRatio;
canvas.width = res[0].width * dpr;
canvas.height = res[0].height * dpr;
ctx.scale(dpr, dpr);
wx.getImageInfo({
src: qrcode,
success: function(res) {
var r = 0, g = 0, b = 0;
for (var i = 0; i < res.width; i++) {
for (var j = 0; j < res.height; j++) {
var imgData = ctx.getImageData(i * 2, j * 2, 1, 1).data;
r += imgData[0];
g += imgData[1];
b += imgData[2];
}
}
var count = res.width * res.height;
r = Math.round(r / count);
g = Math.round(g / count);
b = Math.round(b / count);
var color = 'rgb(' + r + ',' + g + ',' + b + ')';
ctx.fillStyle = color;
ctx.fillRect(0, 0, canvas.width, canvas.height);
ctx.drawImage(qrcode, 20, 20, canvas.width - 40, canvas.height - 40);
wx.canvasToTempFilePath({
canvas: canvas,
success: function(res) {
var qrcode = res.tempFilePath;
that.setData({
qrcode: qrcode
})
}
})
}
})
})
}
})
```
上述代码会在页面中创建一个名为“qrcode”的canvas元素,并在页面加载时调用createQRCode方法生成二维码。createQRCode方法会使用wx.request方法向微信服务器请求生成二维码图片,并将返回的二进制数据转换为base64格式,最后调用drawQRCode方法将base64格式的图片绘制到canvas上,并转换为临时文件路径。drawQRCode方法会使用wx.createSelectorQuery方法获取canvas的宽度和高度,并调用wx.getImageInfo方法获取二维码图片的平均颜色,然后将平均颜色绘制到canvas背景上,并绘制二维码图片。最后调用wx.canvasToTempFilePath方法将canvas转换为临时文件路径,并将路径更新到页面数据中,这样就可以在页面中显示生成的二维码图片。