微信小程序—给图片添加相框_小程序相框处理

直接上效果：

体验：

思路：

1、通过离屏画布（或者置于屏幕外的画布）将图片与中空png格式的相框叠加绘制（绘制需要计算图片尺寸、相框尺寸与画布宽高的关系）
2、通过wx.canvasToTempFilePath将画布上绘制的内容导成图片即可

代码：

js

Page({

  /**
   * 页面的初始数据
   */
  data: {
    canvasWidth:0,
    canvasHeight:0,
    tempCtx:{},
    oriFile:"cloud://normal-env-ta6-normal-e0924598/frame/",
    frameSrcs: [{ src: 'frame1.png', title: '文艺小清新' }, { src: 'frame2.png', title: 'Happy Birthday' }, { src: 'frame3.png', title: '素描花环' }, { src: 'frame4.png', title: '文艺小清新' }, { src: 'frame5.png', title: '卡通小屋' }, { src: 'frame6.png', title: '爱心相框' }, { src: 'frame7.png', title: '心形云朵' }, { src: 'frame8.png', title: '爱心花环' }, { src: 'frame9.png', title: '拍立得相框' }, { src: 'frame10.png', title: '文艺小清新' }, { src: 'frame11.png', title: '贴纸' }]
  },
  chooseFrame(e){
    var that = this
    var index = e.currentTarget.dataset.index
    wx.chooseImage({
      count: 1, // 默认9
      sizeType: ['compressed'], // 指定只能为压缩图，首先进行一次默认压缩
      sourceType: ['album', 'camera'], // 可以指定来源是相册还是相机，默认二者都有
      success: function(res) {
        wx.showLoading({
          title: '正在添加相框',
        })
        var tempFilePath = res.tempFilePaths[0]
        wx.cloud.getTempFileURL({
          fileList: [that.data.oriFile+that.data.frameSrcs[index].src],
          success: res => {
            console.log(res.fileList)
            wx.getImageInfo({
                src: res.fileList[0].tempFileURL,
              success:res =>{
                var frameData = res
                that.setData({
                  canvasWidth: frameData.width,
                  canvasHeight: frameData.height
                })
                wx.getImageInfo({
                  src: tempFilePath,
                  success: res => {
                    var photoData = res
                    console.log("相框", frameData)
                    console.log("相片", photoData)
                    //计算比例
                    var widthRatio = photoData.width/frameData.width
                    var heightRatio = photoData.height/frameData.height
                    //先画照片
                    if(widthRatio<heightRatio){
                      that.data.tempCtx.drawImage(photoData.path, 0, 0, photoData.width, that.data.canvasHeight*widthRatio, 0, 0, that.data.canvasWidth, that.data.canvasHeight)
                    } else {
                      that.data.tempCtx.drawImage(photoData.path, 0, 0, that.data.canvasWidth*heightRatio, photoData.height, 0, 0, that.data.canvasWidth, that.data.canvasHeight)
                    }
                    //再画相框
                    that.data.tempCtx.drawImage(frameData.path, 0, 0, frameData.width, frameData.height, 0, 0, that.data.canvasWidth, that.data.canvasHeight)
                    that.data.tempCtx.draw()
                    var timeId = setTimeout(function () {
                      console.log("延时1秒回调")
                      wx.canvasToTempFilePath({
                        canvasId: 'tempCanvas',
                        fileType: "jpg",
                        success: function (res) {
                          wx.hideLoading()
                          console.log(res.tempFilePath)
                          wx.previewImage({
                            urls: [res.tempFilePath],
                          })
                          clearTimeout(timeId)
                        }
                      })
                    }, 1000)
                  }
                })
              }
            })
          },
          fail: console.error
        })
      },
    })
  },
  /**
   * 生命周期函数--监听页面加载
   */
  onLoad: function (options) {
    var tempCtx = wx.createCanvasContext('tempCanvas')
    this.setData({
      tempCtx:tempCtx
    })
  }
})
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89

wxml

<view class="container">
  <canvas canvas-id="tempCanvas" style="background:#ed3;width:{{canvasWidth}}px;height:{{canvasHeight}}px;position:absolute;left:-999999px"></canvas>
  <scroll-view style="width:100%;height:500px"  scroll-y>
      <view wx:for="{{frameSrcs}}" wx:key="unique" class="frameBox" data-index="{{index}}"  bindtap='chooseFrame'>
        <image src="{{oriFile+item.src}}" mode="aspectFit"></image>
        <text>{{item.title}}</text>
      </view>
    </scroll-view>
</view>
1
2
3
4
5
6
7
8
9

wxss

.imagePhoto{
  position: fixed;
  z-index: 1000;
  top: 100px;
}
.imageFrame{
  position: fixed;
  z-index: 1001;
  top:100px;
}
.frameBox{
  display: inline-block;
  width:300rpx;
  height:360rpx;
  margin: 30rpx 35rpx;
  border:1rpx solid #ccc;
  overflow: hidden;
  text-align: center;
}
.frameBox:active{
  background-color: white;
}
.frameBox image{
  width:100%;
  height:300rpx;
}
.frameBox text{
  font-size: 30rpx;
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29