微信小程序&PHP 生成小程序码分享图 并保存在手机相册

注意：小程序端如果想保存成图片，需要用画布，但是如果想把图片放在画布上，真机上需要先把图片保存到本地。使用缓存文件！！！！！

小程序端：

  .js

import util from '../../../utils/util'
var image = require('../../../utils/util.js'); 
const app = getApp(); 
Page({
  data: {
    allthing: app.globalData,
  },
  onLoad: function (options) {
    var that = this;
    var imageSize = image.image()
    console.log(imageSize)
    that.setData({
      imageWidth: imageSize.imageWidth,
      imageHeight: imageSize.imageHeight,
      chaWidth: imageSize.chaWidth,
      chaHeight: imageSize.chaHeight,
    })
    that.getAvatarUrl(that.data.allthing.userInfo.avatarUrl)
    that.getSpecialM()
    that.getBackground()
    that.getTouground()
    wx.showToast({
      title: '正在生成图片',
      icon: 'loading',
      duration: 10000,
    })
    setTimeout(function () {           //延迟执行，避免请求文件无效
      console.log("----Countdown----")
      that.createImg()
      wx.hideToast()
    }, 1000)
  },
  /**
   * 获取特定页面的小程序码
   */
  getSpecialM:function(){
    var that = this
    //请求获取小程序码
    wx.request({
      method: 'GET',
      url: 'https://www.a******_code.php?sid=' + that.data.userInfo.subject_id,//小程序有关token的api接口需要写在后台服务器端
      header: {
        'content-type': 'application/json'
      },
      success: function (res) {
        console.log(res)
        wx.downloadFile({
          url: res.data.data.url,
          success: function (res) {
            that.setData({
              icon4: res.tempFilePath,
            })
          },
          fail: function () {
            console.log('fail')
          }
        })
      }
  })
},
  /**
   * 获取头像
   */
  getAvatarUrl: function (avatarUrl){
    var that = this
    //保存头像
    wx.downloadFile({
      url:avatarUrl,
      success: function (res) {
        that.setData({
          exam: res.tempFilePath,
        })
      },
      fail: function () {
        console.log('fail')
      }
    })
  },
  /**
   * 获取背景
   */
  getBackground: function () {
    var that = this
    wx.downloadFile({
      url: 'https://app.c***answer/2.png',
      success: function (res) {
        that.setData({
          share: res.tempFilePath,
        })
      },
      fail: function () {
        console.log('fail')
      }
    })
  },
  /**
   * 获取头像框
   */
  getTouground: function () {
    var that = this
    wx.downloadFile({
      url: 'https://app.ci1*******er/phot.png',
      success: function (res) {
        that.setData({
          phot: res.tempFilePath,
        })
      },
      fail: function () {
        console.log('fail')
      }
    })
  },
  /**
   * 生成画布
   */
  createImg:function(){
    var that  = this 
    var ctx = wx.createCanvasContext('myCanvas');
    ctx.setFillStyle('White')
    ctx.fillRect(0, 0, 300, 400)
    ctx.drawImage(that.data.icon4, 115 + that.data.chaWidth / 2, 153 + that.data.chaHeight / 2, 92, 92)
    ctx.drawImage(that.data.share, 0, 0, that.data.imageWidth, that.data.imageHeight)
    ctx.drawImage(that.data.exam, 138 + that.data.chaWidth / 2, 10 , 50, 50)
    ctx.drawImage(that.data.phot, 138 + that.data.chaWidth / 2, 10, 50, 50)
    ctx.draw();
  },
  savePic: function () {       //保存图片触发事件
    var that = this
    wx.canvasToTempFilePath({
      width: that.data.imageWidth,
      height: that.data.imageHeight,
      canvasId: 'myCanvas',
      success: function (res) {
        util.savePicToAlbum(res.tempFilePath)
      }
    })
    setTimeout(function () {
      console.log("----Countdown----")
      wx.redirectTo({
        url: '/pages/my/my/my',
      })
    }, 1000)
   
  }
})

.wxml

<view>
    <canvas style="width:{{imageWidth}}px;height:{{imageHeight}}px" canvas-id="myCanvas" class='canvas'></canvas>
    <!--测试按钮-->
    <view class="edit-footer">
        <button class="button-done" type="primary" bindtap="savePic">保存图片</button>
    </view>
</view>

util.js

function savePicToAlbum(tempFilePath) {
  let that = this;
  wx.getSetting({
    success(res) {
      if (!res.authSetting['scope.writePhotosAlbum']) {
        wx.authorize({
          scope: 'scope.writePhotosAlbum',
          success() {
            wx.saveImageToPhotosAlbum({
              filePath: tempFilePath,
              success(res) {
                wx.showToast({
                  title: '保存成功'
                });
              },
              fail(res) {
                console.log(res);
              }
            })
          },
          fail() {
            // 用户拒绝授权,打开设置页面
            wx.openSetting({
              success: function (data) {
                console.log("openSetting: success");
              },
              fail: function (data) {
                console.log("openSetting: fail");
              }
            });
          }
        })
      } else {
        wx.saveImageToPhotosAlbum({
          filePath: tempFilePath,
          success(res) {
            wx.showToast({
              title: '保存成功',
            });
          },
          fail(res) {
            console.log(res);
          }
        })
      }
    },
    fail(res) {
      console.log(res);
    }
  })
}
function image() {
  var imageSize = {};
  var originalScale = 0.2;//图片高宽比  
  //获取屏幕宽高  
  wx.getSystemInfo({
    success: function (res) {
      var windowWidth = res.windowWidth;
      var windowHeight = res.windowHeight;
      var windowscale = windowHeight / windowWidth;//屏幕高宽比  
      console.log('windowWidth: ' + windowWidth)
      console.log('windowHeight: ' + windowHeight)
      if (originalScale < windowscale) {//图片高宽比小于屏幕高宽比  
        //图片缩放后的宽为屏幕宽  
        imageSize.imageWidth = windowWidth;
        imageSize.imageHeight = (windowWidth * 400) / 320;
        imageSize.chaWidth = windowWidth-320; 
        imageSize.chaHeight = (windowWidth * 400) / 320 - 400; 
      } else {//图片高宽比大于屏幕高宽比  
        //图片缩放后的高为屏幕高  
        imageSize.imageHeight = windowHeight;
        imageSize.imageWidth = (windowHeight * 320) / 400;
        imageSize.chaWidth = windowWidth - 320;
        imageSize.chaHeight = (windowWidth * 400) / 320 - 400; 
      }

    }
  })
  console.log('缩放后的宽: ' + imageSize.imageWidth)
  console.log('缩放后的高: ' + imageSize.imageHeight)
  return imageSize;
}
module.exports = {
  formatTime: formatTime,
  savePicToAlbum: savePicToAlbum,
  image:image
}

服务器端

create_wxa_code.php

<?php
include_once('/opt*****/function.php');
include_once('/opt*****n/config.php');//$appid和$secret保存其中
$sid = addslashes($_GET['sid']);
//token存在缓存中
$access_token=M::Get('q*******en_'.$appid);
if(!$access_token){
        $url_access_token = 'https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid='.$appid.'&secret='.$secret;
        $json_access_token = sendCmd($url_access_token,array());
        //access_token加缓存
        $arr_access_token = json_decode($json_access_token,true);
        $access_token = $arr_access_token['access_token'];
        M::Set('q******ken_'.$appid,$access_token,3600);
}
if(!empty($access_token)) {
	$url = 'https://api.weixin.qq.com/wxa/getwxacode?access_token='.$access_token;    
 	$data = '{"path": "/pages/a*****/index?id='.$sid.'", "width":430}';
     	$result = sendCmd($url,$data);

	$dir = "/opt/c******wxaapp/";
	$path = $dir.date("Y/m/d/")."/".rand(1,50)."/";
	create_dirs($path,0777);
	$file_name = time().".png";
		
	file_put_contents($path.$file_name,$result);
	$url = 'https://www.q****om/'.str_replace('/op*****baby/','',$path.$file_name);

	$arr = array('ret'=>1,
		'msg'=>'success',
		'data'=>array('url'=>$url),   //返回保存在服务器中小程序码的地址
		);
} else {
	$arr = array('ret'=>0,'msg'=>'ACCESS TOKEN为空！');
}
	echo json_encode($arr);


/**
 * 发起请求
 * @param  string $url  请求地址
 * @param  string $data 请求数据包
 * @return   string      请求返回数据
 */
function sendCmd($url,$data)
{
    $curl = curl_init(); // 启动一个CURL会话      
    curl_setopt($curl, CURLOPT_URL, $url); // 要访问的地址                  
    curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, 0); // 对认证证书来源的检测    
    curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, 2); // 从证书中检查SSL加密算法是否存在      
    curl_setopt($curl, CURLOPT_HTTPHEADER, array('Expect:')); //解决数据包大不能提交     
    curl_setopt($curl, CURLOPT_FOLLOWLOCATION, 1); // 使用自动跳转      
    curl_setopt($curl, CURLOPT_AUTOREFERER, 1); // 自动设置Referer      
    curl_setopt($curl, CURLOPT_POST, 1); // 发送一个常规的Post请求      
    curl_setopt($curl, CURLOPT_POSTFIELDS, $data); // Post提交的数据包      
    curl_setopt($curl, CURLOPT_TIMEOUT, 30); // 设置超时限制防止死循     
    curl_setopt($curl, CURLOPT_HEADER, 0); // 显示返回的Header区域内容      
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1); // 获取的信息以文件流的形式返回 
           
    $tmpInfo = curl_exec($curl); // 执行操作      
    if (curl_errno($curl)) {      
       echo 'Errno'.curl_error($curl);      
    }      
    curl_close($curl); // 关键CURL会话      
    return $tmpInfo; // 返回数据      
}
?>