微信小程序如何实现裁剪图片大小
这篇文章主要介绍“微信小程序如何实现裁剪图片大小”，在日常操作中，相信很多人在微信小程序如何实现裁剪图片大小问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答”微信小程序如何实现裁剪图片大小”的疑惑有所帮助！接下来，请跟着小编一起来学习吧！
效果图
.wxml
<button bindtap="uploadtap">上传图片</button>
<image mode="widthFix" src="{{canfile_image}}"></image>
<canvas canvas-id="myCanvas" id="myCanvas" ></canvas>
<view class="canvas_model" wx:if="{{canvas_arr.show}}" catchtouchmove="setTouchMove">
<view class="canvas_view"
bindtouchstart="handletouchstart" bindtouchmove="handletouchmove">
<image src="{{canvas_arr.src}}"></image>
<view >
<view class="canvas_horn" >
<view></view>
<view></view>
<view></view>
<view></view>
<view></view>
<view></view>
<image src="{{canvas_arr.src}}"></image>
</view>
</view>
</view>
<view class="canvas_bar" wx:if="{{cutting.show}}">
<view bindtap="color_tap">×</view>
<view class="bar_tab {{color_status?'tab_cation':''}}" bindtap="color_tap" data-type="1">
<view>浅色</view>
<view>深色</view>
<view></view>
</view>
<view bindtap="ationimg">√</view>
</view>
</view>.wxss
.canvas_model{width: 100%;height: 100vh;position: fixed;left: 0;top: 0;background: rgba(0, 0, 0, 0.6);z-index: 10;
display:flex;justify-content: center;padding-top: 10vh;animation:model 0.3s;}
@keyframes model{
from { opacity: 0;transform: scale(0.5); }
to { opacity:1;transform: scale(1); }
}
.canvas_view{float: left;position: relative;}
.canvas_view>view{width: 100%;height: 100%;position: absolute;left: 0;top: 0;background: rgba(255, 255, 255, 0.4);transition: all 0.3s;}
.canvas_horn{position: absolute;left: 0;width: 100%;overflow: hidden;}
.canvas_horn>view{width: 40rpx;height: 40rpx;position: absolute;z-index: 1;}
.canvas_horn>image{position: absolute;left: 0;top: 0;}
.canvas_horn>view:nth-child(1){border-left: 2px solid #fff;border-top: 2px solid #fff;left: 0;top: 0;}
.canvas_horn>view:nth-child(2){border-right: 2px solid #fff;border-top: 2px solid #fff;right: 0;top: 0;}
.canvas_horn>view:nth-child(3){border-left: 2px solid #fff;border-bottom:2px solid #fff;left: 0;bottom: 0;}
.canvas_horn>view:nth-child(4){border-right: 2px solid #fff;border-bottom: 2px solid #fff;right: 0;bottom: 0;}
.canvas_horn>view:nth-child(5){width: 60rpx;height: 2px;background: #fff;top: 0;left: 0;right: 0;margin: 0 auto;}
.canvas_horn>view:nth-child(6){width: 60rpx;height: 2px;background: #fff;bottom: 0;left: 0;right: 0;margin: 0 auto;}
.canvas_bar{width: 100%;height: 14vh;display: flex;align-items: center;justify-content: space-between;background: #fff;
position: absolute;left: 0;bottom: 0;animation:bartion 0.5s;}
@keyframes bartion{
from { bottom: -14vh; }
to { bottom: 0; }
}
.canvas_bar>view:nth-child(1),.canvas_bar>view:nth-child(3){width: 160rpx;height: 100%;display: flex;align-items: center;
justify-content: center;font-size: 44rpx;font-weight: 700;}
.bar_tab{width: 300rpx;display: flex;height: 60rpx;border-radius: 10rpx;border: 1px solid #f4f4f4;line-height: 60rpx;
position: relative;font-size: 24rpx;color: #333;}
.bar_tab>view{width: 50%;height: 100%;text-align: center;position: relative;z-index: 1;transition: all 0.3s;}
.bar_tab>view:nth-child(1){color: #fff;}
.bar_tab>view:nth-child(3){position: absolute;left: 0;top: 0;background: #0081ff;border-radius: 10rpx;z-index: 0;}
.tab_cation>view:nth-child(1){color: #000;}
.tab_cation>view:nth-child(2){color: #fff;}
.tab_cation>view:nth-child(3){left: 50%;}
#myCanvas{position: absolute;left: 0;top: -71vh;z-index: -1;opacity: 0;}.js
Page({
data: {
canvas_arr:{
src:'',
width:parseInt(wx.getSystemInfoSync().windowWidth * 0.9),
height:parseInt(wx.getSystemInfoSync().windowHeight * 0.7),
show:false
},
cutting:{
height:0,
max_y:0,
show:false
},
canvas_y:0,
color_status:false,
canfile_image:'',
},
color_tap(e){
var type = e?e.currentTarget.dataset.type:0
if(type == 1){
this.setData({
color_status:!this.data.color_status
})
}else{
this.data.canvas_arr.show = false
this.data.canvas_arr.height = parseInt(wx.getSystemInfoSync().windowHeight * 0.7)
this.data.cutting.show = false
this.data.cutting.src = ''
this.setData({
canvas_arr:this.data.canvas_arr,
cutting:this.data.cutting,
canvas_y:0,
})
}
},
setTouchMove(e){return;},
uploadtap(e){
var that = this
wx.chooseImage({
count:1,
success (res) {
const tempFilePaths = res.tempFilePaths[0]
that.data.canvas_arr.src = tempFilePaths
wx.getImageInfo({
src: tempFilePaths,
success (res) {
that.data.canvas_arr.show = true
that.data.cutting.show = true
that.data.cutting.height = that.data.canvas_arr.width / 2
var height = parseInt(res.height / (res.width / that.data.canvas_arr.width))
that.data.canvas_arr.height = height > that.data.canvas_arr.height ? that.data.canvas_arr.height : height
that.data.cutting.max_y = that.data.canvas_arr.height - that.data.cutting.height
that.setData({
canvas_arr:that.data.canvas_arr
})
setTimeout(function () {
that.setData({
cutting:that.data.cutting
})
},500)
}
})
}
})
},
handletouchstart: function (e) {
this.data.startY = e.touches[0].clientY
},
handletouchmove (e) {
let currentY = e.touches[0].clientY - this.data.startY
if(currentY > 0){
this.setData({
canvas_y:currentY > this.data.cutting.max_y?this.data.cutting.max_y:currentY,
})
}else{
this.setData({
canvas_y:0
})
}
},
ationimg(e){
var that = this
var canvas_img = wx.createCanvasContext('myCanvas')
canvas_img.width = that.data.canvas_arr.width
canvas_img.height = that.data.canvas_arr.height
canvas_img.drawImage(that.data.canvas_arr.src,0,0,canvas_img.width,canvas_img.height)
canvas_img.draw(true,(()=>{
wx.canvasToTempFilePath({
x: 0,
y: that.data.canvas_y,
width:that.data.canvas_arr.width,
height:that.data.cutting.height,
canvasId: 'myCanvas',
success: function (res) {
that.setData({
canfile_image:res.tempFilePath
})
that.color_tap()
wx.showToast({
title: '裁剪成功~',
icon: 'none',
duration: 3000
})
}
});
}))
},
})功能主要针对轮播图片尺寸，不合适可自行修改比例
到此，关于“微信小程序如何实现裁剪图片大小”的学习就结束了，希望能够解决大家的疑惑。理论与实践的搭配能更好的帮助大家学习，快去试试吧！若想继续学习更多相关知识，请继续关注蜗牛博客网站，小编会继续努力为大家带来更多实用的文章！
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