uni-app 圖片裁剪
hbuilderX 官方demo 中有這個示例，可直接使用
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<
template
>
<
view
class
=
"container"
>
<
view
class
=
"page-body uni-content-info"
>
<
view
class
=
'cropper-content'
>
<
view
v-if
=
"isShowImg"
class
=
"uni-corpper"
:style
=
"'width:'+cropperInitW+'px;height:'+cropperInitH+'px;background:#000'"
>
<
view
class
=
"uni-corpper-content"
:style
=
"'width:'+cropperW+'px;height:'+cropperH+'px;left:'+cropperL+'px;top:'+cropperT+'px'"
>
<
image
:src
=
"imageSrc"
:style
=
"'width:'+cropperW+'px;height:'+cropperH+'px'"
></
image
>
<
view
class
=
"uni-corpper-crop-box"
@
touchstart.stop
=
"contentStartMove"
@
touchmove.stop
=
"contentMoveing"
@
touchend.stop
=
"contentTouchEnd"
:style
=
"'left:'+cutL+'px;top:'+cutT+'px;right:'+cutR+'px;bottom:'+cutB+'px'"
>
<
view
class
=
"uni-cropper-view-box"
>
<
view
class
=
"uni-cropper-dashed-h"
></
view
>
<
view
class
=
"uni-cropper-dashed-v"
></
view
>
<
view
class
=
"uni-cropper-line-t"
data-drag
=
"top"
@
touchstart.stop
=
"dragStart"
@
touchmove.stop
=
"dragMove"
></
view
>
<
view
class
=
"uni-cropper-line-r"
data-drag
=
"right"
@
touchstart.stop
=
"dragStart"
@
touchmove.stop
=
"dragMove"
></
view
>
<
view
class
=
"uni-cropper-line-b"
data-drag
=
"bottom"
@
touchstart.stop
=
"dragStart"
@
touchmove.stop
=
"dragMove"
></
view
>
<
view
class
=
"uni-cropper-line-l"
data-drag
=
"left"
@
touchstart.stop
=
"dragStart"
@
touchmove.stop
=
"dragMove"
></
view
>
<
view
class
=
"uni-cropper-point point-t"
data-drag
=
"top"
@
touchstart.stop
=
"dragStart"
@
touchmove.stop
=
"dragMove"
></
view
>
<
view
class
=
"uni-cropper-point point-tr"
data-drag
=
"topTight"
></
view
>
<
view
class
=
"uni-cropper-point point-r"
data-drag
=
"right"
@
touchstart.stop
=
"dragStart"
@
touchmove.stop
=
"dragMove"
></
view
>
<
view
class
=
"uni-cropper-point point-rb"
data-drag
=
"rightBottom"
@
touchstart.stop
=
"dragStart"
@
touchmove.stop
=
"dragMove"
></
view
>
<
view
class
=
"uni-cropper-point point-b"
data-drag
=
"bottom"
@
touchstart.stop
=
"dragStart"
@
touchmove.stop
=
"dragMove"
@
touchend.stop
=
"dragEnd"
></
view
>
<
view
class
=
"uni-cropper-point point-bl"
data-drag
=
"bottomLeft"
></
view
>
<
view
class
=
"uni-cropper-point point-l"
data-drag
=
"left"
@
touchstart.stop
=
"dragStart"
@
touchmove.stop
=
"dragMove"
></
view
>
<
view
class
=
"uni-cropper-point point-lt"
data-drag
=
"leftTop"
></
view
>
</
view
>
</
view
>
</
view
>
</
view
>
</
view
>
<
view
class
=
'cropper-config'
>
<
button
type
=
"primary reverse"
@
click
=
"getImage"
style
=
'margin-top: 30upx;'
> 選擇圖片 </
button
>
<
button
type
=
"warn"
@
click
=
"getImageInfo"
style
=
'margin-top: 30upx;'
> 點擊生成圖片 </
button
>
</
view
>
<
canvas
canvas-id
=
"myCanvas"
:style
=
"'position:absolute;border: 1px solid red; width:'+imageW+'px;height:'+imageH+'px;top:-9999px;left:-9999px;'"
></
canvas
>
</
view
>
<
page-foot
:name
=
"name"
></
page-foot
>
</
view
>
</
template
>
<
script
>
let sysInfo = uni.getSystemInfoSync();
let SCREEN_WIDTH = sysInfo.screenWidth
let PAGE_X, // 手按下的x位置
PAGE_Y, // 手按下y的位置
PR = sysInfo.pixelRatio, // dpi
T_PAGE_X, // 手移動的時候x的位置
T_PAGE_Y, // 手移動的時候Y的位置
CUT_L, // 初始化拖拽元素的left值
CUT_T, // 初始化拖拽元素的top值
CUT_R, // 初始化拖拽元素的
CUT_B, // 初始化拖拽元素的
CUT_W, // 初始化拖拽元素的寬度
CUT_H, // 初始化拖拽元素的高度
IMG_RATIO, // 圖片比例
IMG_REAL_W, // 圖片實際的寬度
IMG_REAL_H, // 圖片實際的高度
DRAFG_MOVE_RATIO = 1, //移動時候的比例,
INIT_DRAG_POSITION = 100, // 初始化屏幕寬度和裁剪區域的寬度之差，用於設置初始化裁剪的寬度
DRAW_IMAGE_W = sysInfo.screenWidth // 設置生成的圖片寬度
export default {
/**
* 頁面的初始數據
*/
data() {
return {
name:'楊大寶',
imageSrc: 'https://img-cdn-qiniu.dcloud.net.cn/demo_crop.jpg',
isShowImg: false,
// 初始化的寬高
cropperInitW: SCREEN_WIDTH,
cropperInitH: SCREEN_WIDTH,
// 動態的寬高
cropperW: SCREEN_WIDTH,
cropperH: SCREEN_WIDTH,
// 動態的left top值
cropperL: 0,
cropperT: 0,
transL: 0,
transT: 0,
// 圖片縮放值
scaleP: 0,
imageW: 0,
imageH: 0,
// 裁剪框 寬高
cutL: 0,
cutT: 0,
cutB: SCREEN_WIDTH,
cutR: '100%',
qualityWidth: DRAW_IMAGE_W,
innerAspectRadio: DRAFG_MOVE_RATIO
}
},
/**
* 生命周期函數--監聽頁面加載
*/
onLoad: function (options) {},
/**
* 生命周期函數--監聽頁面初次渲染完成
*/
onReady: function () {
this.loadImage();
},
methods: {
setData: function (obj) {
let that = this;
Object.keys(obj).forEach(function (key) {
that.$set(that.$data, key, obj[key])
});
},
getImage: function () {
var _this = this
uni.chooseImage({
success: function (res) {
_this.setData({
imageSrc: res.tempFilePaths[0],
})
_this.loadImage();
},
})
},
loadImage: function () {
var _this = this
uni.showLoading({
title: '圖片加載中...',
})
uni.getImageInfo({
src: _this.imageSrc,
success: function success(res) {
IMG_RATIO = res.width / res.height
if (IMG_RATIO >= 1) {
IMG_REAL_W = SCREEN_WIDTH
IMG_REAL_H = SCREEN_WIDTH / IMG_RATIO
} else {
IMG_REAL_W = SCREEN_WIDTH * IMG_RATIO
IMG_REAL_H = SCREEN_WIDTH
}
let minRange = IMG_REAL_W > IMG_REAL_H ? IMG_REAL_W : IMG_REAL_H
INIT_DRAG_POSITION = minRange > INIT_DRAG_POSITION ? INIT_DRAG_POSITION : minRange
// 根據圖片的寬高顯示不同的效果 保證圖片可以正常顯示
if (IMG_RATIO >= 1) {
let cutT = Math.ceil((SCREEN_WIDTH / IMG_RATIO - (SCREEN_WIDTH / IMG_RATIO - INIT_DRAG_POSITION)) / 2);
let cutB = cutT;
let cutL = Math.ceil((SCREEN_WIDTH - SCREEN_WIDTH + INIT_DRAG_POSITION) / 2);
let cutR = cutL;
_this.setData({
cropperW: SCREEN_WIDTH,
cropperH: SCREEN_WIDTH / IMG_RATIO,
// 初始化left right
cropperL: Math.ceil((SCREEN_WIDTH - SCREEN_WIDTH) / 2),
cropperT: Math.ceil((SCREEN_WIDTH - SCREEN_WIDTH / IMG_RATIO) / 2),
cutL: cutL,
cutT: cutT,
cutR: cutR,
cutB: cutB,
// 圖片縮放值
imageW: IMG_REAL_W,
imageH: IMG_REAL_H,
scaleP: IMG_REAL_W / SCREEN_WIDTH,
qualityWidth: DRAW_IMAGE_W,
innerAspectRadio: IMG_RATIO
})
} else {
let cutL = Math.ceil((SCREEN_WIDTH * IMG_RATIO - (SCREEN_WIDTH * IMG_RATIO)) / 2);
let cutR = cutL;
let cutT = Math.ceil((SCREEN_WIDTH - INIT_DRAG_POSITION) / 2);
let cutB = cutT;
_this.setData({
cropperW: SCREEN_WIDTH * IMG_RATIO,
cropperH: SCREEN_WIDTH,
// 初始化left right
cropperL: Math.ceil((SCREEN_WIDTH - SCREEN_WIDTH * IMG_RATIO) / 2),
cropperT: Math.ceil((SCREEN_WIDTH - SCREEN_WIDTH) / 2),
cutL: cutL,
cutT: cutT,
cutR: cutR,
cutB: cutB,
// 圖片縮放值
imageW: IMG_REAL_W,
imageH: IMG_REAL_H,
scaleP: IMG_REAL_W / SCREEN_WIDTH,
qualityWidth: DRAW_IMAGE_W,
innerAspectRadio: IMG_RATIO
})
}
_this.setData({
isShowImg: true
})
uni.hideLoading()
}
})
},
// 拖動時候觸發的touchStart事件
contentStartMove(e) {
PAGE_X = e.touches[0].pageX
PAGE_Y = e.touches[0].pageY
},
// 拖動時候觸發的touchMove事件
contentMoveing(e) {
var _this = this
var dragLengthX = (PAGE_X - e.touches[0].pageX) * DRAFG_MOVE_RATIO
var dragLengthY = (PAGE_Y - e.touches[0].pageY) * DRAFG_MOVE_RATIO
// 左移
if (dragLengthX > 0) {
if (this.cutL - dragLengthX <
0
)
dragLengthX
=
this
.cutL
} else {
if (this.cutR + dragLengthX < 0) dragLengthX = -this.cutR
}
if (dragLengthY > 0) {
if (this.cutT - dragLengthY <
0
)
dragLengthY
=
this
.cutT
} else {
if (this.cutB + dragLengthY < 0) dragLengthY = -this.cutB
}
this.setData({
cutL: this.cutL - dragLengthX,
cutT: this.cutT - dragLengthY,
cutR: this.cutR + dragLengthX,
cutB: this.cutB + dragLengthY
})
PAGE_X
=
e
.touches[0].pageX
PAGE_Y
=
e
.touches[0].pageY
},
contentTouchEnd() {
},
// 獲取圖片
getImageInfo() {
var
_this
= this;
uni.showLoading({
title: '圖片生成中...',
});
// 將圖片寫入畫布
const
ctx
=
uni
.createCanvasContext('myCanvas');
ctx.drawImage(_this.imageSrc, 0, 0, IMG_REAL_W, IMG_REAL_H);
ctx.draw(true, () => {
// 獲取畫布要裁剪的位置和寬度 均為百分比 * 畫布中圖片的寬度 保證了在微信小程序中裁剪的圖片模糊 位置不對的問題 canvasT = (_this.cutT / _this.cropperH) * (_this.imageH / pixelRatio)
var canvasW = ((_this.cropperW - _this.cutL - _this.cutR) / _this.cropperW) * IMG_REAL_W;
var canvasH = ((_this.cropperH - _this.cutT - _this.cutB) / _this.cropperH) * IMG_REAL_H;
var canvasL = (_this.cutL / _this.cropperW) * IMG_REAL_W;
var canvasT = (_this.cutT / _this.cropperH) * IMG_REAL_H;
uni.canvasToTempFilePath({
x: canvasL,
y: canvasT,
width: canvasW,
height: canvasH,
destWidth: canvasW,
destHeight: canvasH,
quality: 0.5,
canvasId: 'myCanvas',
success: function (res) {
uni.hideLoading()
// 成功獲得地址的地方
uni.previewImage({
current: '', // 當前顯示圖片的http鏈接
urls: [res.tempFilePath] // 需要預覽的圖片http鏈接列表
})
}
});
});
},
// 設置大小的時候觸發的touchStart事件
dragStart(e) {
T_PAGE_X = e.touches[0].pageX
T_PAGE_Y = e.touches[0].pageY
CUT_L = this.cutL
CUT_R = this.cutR
CUT_B = this.cutB
CUT_T = this.cutT
},
// 設置大小的時候觸發的touchMove事件
dragMove(e) {
var _this = this
var dragType = e.target.dataset.drag
switch (dragType) {
case 'right':
var dragLength = (T_PAGE_X - e.touches[0].pageX) * DRAFG_MOVE_RATIO
if (CUT_R + dragLength <
0
) dragLength = -CUT_R
this.setData({
cutR: CUT_R + dragLength
})
break;
case 'left':
var dragLength = (T_PAGE_X - e.touches[0].pageX) * DRAFG_MOVE_RATIO
if (CUT_L - dragLength < 0)
dragLength
=
CUT_L
if ((CUT_L - dragLength) > (this.cropperW - this.cutR)) dragLength = CUT_L - (this.cropperW - this.cutR)
this.setData({
cutL: CUT_L - dragLength
})
break;
case 'top':
var dragLength = (T_PAGE_Y - e.touches[0].pageY) * DRAFG_MOVE_RATIO
if (CUT_T - dragLength <
0
)
dragLength
=
CUT_T
if ((CUT_T - dragLength) > (this.cropperH - this.cutB)) dragLength = CUT_T - (this.cropperH - this.cutB)
this.setData({
cutT: CUT_T - dragLength
})
break;
case 'bottom':
var dragLength = (T_PAGE_Y - e.touches[0].pageY) * DRAFG_MOVE_RATIO
if (CUT_B + dragLength <
0
) dragLength = -CUT_B
this.setData({
cutB: CUT_B + dragLength
})
break;
case 'rightBottom':
var dragLengthX = (T_PAGE_X - e.touches[0].pageX) * DRAFG_MOVE_RATIO
var dragLengthY = (T_PAGE_Y - e.touches[0].pageY) * DRAFG_MOVE_RATIO
if (CUT_B + dragLengthY < 0) dragLengthY = -CUT_B
if (CUT_R + dragLengthX < 0) dragLengthX = -CUT_R
let
cutB
=
CUT_B
+ dragLengthY;
let
cutR
=
CUT_R
+ dragLengthX;
this.setData({
cutB: cutB,
cutR: cutR
})
break;
default:
break;
}
}
}
}
</script>
<
style
>
/* pages/uni-cropper/index.wxss */
.uni-content-info {
/* position: fixed;
top: 0;
left: 0;
right: 0;
bottom: 0;
display: block;
align-items: center;
flex-direction: column; */
}
.cropper-config {
padding: 20upx 40upx;
}
.cropper-content {
min-height: 750upx;
width: 100%;
}
.uni-corpper {
position: relative;
overflow: hidden;
-webkit-user-select: none;
-moz-user-select: none;
-ms-user-select: none;
user-select: none;
-webkit-tap-highlight-color: transparent;
-webkit-touch-callout: none;
box-sizing: border-box;
}
.uni-corpper-content {
position: relative;
}
.uni-corpper-content image {
display: block;
width: 100%;
min-width: 0 !important;
max-width: none !important;
height: 100%;
min-height: 0 !important;
max-height: none !important;
image-orientation: 0deg !important;
margin: 0 auto;
}
/* 移動圖片效果 */
.uni-cropper-drag-box {
position: absolute;
top: 0;
right: 0;
bottom: 0;
left: 0;
cursor: move;
background: rgba(0, 0, 0, 0.6);
z-index: 1;
}
/* 內部的信息 */
.uni-corpper-crop-box {
position: absolute;
background: rgba(255, 255, 255, 0.3);
z-index: 2;
}
.uni-corpper-crop-box .uni-cropper-view-box {
position: relative;
display: block;
width: 100%;
height: 100%;
overflow: visible;
outline: 1upx solid #69f;
outline-color: rgba(102, 153, 255, .75)
}
/* 橫向虛線 */
.uni-cropper-dashed-h {
position: absolute;
top: 33.33333333%;
left: 0;
width: 100%;
height: 33.33333333%;
border-top: 1upx dashed rgba(255, 255, 255, 0.5);
border-bottom: 1upx dashed rgba(255, 255, 255, 0.5);
}
/* 縱向虛線 */
.uni-cropper-dashed-v {
position: absolute;
left: 33.33333333%;
top: 0;
width: 33.33333333%;
height: 100%;
border-left: 1upx dashed rgba(255, 255, 255, 0.5);
border-right: 1upx dashed rgba(255, 255, 255, 0.5);
}
/* 四個方向的線 為了之后的拖動事件*/
.uni-cropper-line-t {
position: absolute;
display: block;
width: 100%;
top: 0;
left: 0;
height: 1upx;
opacity: 0.1;
cursor: n-resize;
}
.uni-cropper-line-t::before {
content: '';
position: absolute;
top: 50%;
right: 0upx;
width: 100%;
-webkit-transform: translate3d(0, -50%, 0);
transform: translate3d(0, -50%, 0);
bottom: 0;
height: 41upx;
background: transparent;
z-index: 11;
}
.uni-cropper-line-r {
position: absolute;
display: block;
top: 0;
right: 0upx;
width: 1upx;
opacity: 0.1;
height: 100%;
cursor: e-resize;
}
.uni-cropper-line-r::before {
content: '';
position: absolute;
top: 0;
left: 50%;
width: 41upx;
-webkit-transform: translate3d(-50%, 0, 0);
transform: translate3d(-50%, 0, 0);
bottom: 0;
height: 100%;
background: transparent;
z-index: 11;
}
.uni-cropper-line-b {
position: absolute;
display: block;
width: 100%;
bottom: 0;
left: 0;
height: 1upx;
opacity: 0.1;
cursor: s-resize;
}
.uni-cropper-line-b::before {
content: '';
position: absolute;
top: 50%;
right: 0upx;
width: 100%;
-webkit-transform: translate3d(0, -50%, 0);
transform: translate3d(0, -50%, 0);
bottom: 0;
height: 41upx;
background: transparent;
z-index: 11;
}
.uni-cropper-line-l {
position: absolute;
display: block;
top: 0;
left: 0;
width: 1upx;
opacity: 0.1;
height: 100%;
cursor: w-resize;
}
.uni-cropper-line-l::before {
content: '';
position: absolute;
top: 0;
left: 50%;
width: 41upx;
-webkit-transform: translate3d(-50%, 0, 0);
transform: translate3d(-50%, 0, 0);
bottom: 0;
height: 100%;
background: transparent;
z-index: 11;
}
.uni-cropper-point {
width: 5upx;
height: 5upx;
opacity: .75;
position: absolute;
z-index: 3;
}
.point-t {
top: -3upx;
left: 50%;
margin-left: -3upx;
cursor: n-resize;
}
.point-tr {
top: -3upx;
left: 100%;
margin-left: -3upx;
cursor: n-resize;
}
.point-r {
top: 50%;
left: 100%;
margin-left: -3upx;
margin-top: -3upx;
cursor: n-resize;
}
.point-rb {
left: 100%;
top: 100%;
-webkit-transform: translate3d(-50%, -50%, 0);
transform: translate3d(-50%, -50%, 0);
cursor: n-resize;
width: 36upx;
height: 36upx;
position: absolute;
z-index: 1112;
opacity: 1;
}
.point-b {
left: 50%;
top: 100%;
margin-left: -3upx;
margin-top: -3upx;
cursor: n-resize;
}
.point-bl {
left: 0%;
top: 100%;
margin-left: -3upx;
margin-top: -3upx;
cursor: n-resize;
}
.point-l {
left: 0%;
top: 50%;
margin-left: -3upx;
margin-top: -3upx;
cursor: n-resize;
}
.point-lt {
left: 0%;
top: 0%;
margin-left: -3upx;
margin-top: -3upx;
cursor: n-resize;
}
/* 裁剪框預覽內容 */
.uni-cropper-viewer {
position: relative;
width: 100%;
height: 100%;
overflow: hidden;
}
.uni-cropper-viewer image {
position: absolute;
z-index: 2;
}
</
style
>
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