问题以及解决：
吐槽遇到的问题~
在写微信小程序的时候，采用wx.canvasToTempFilePath压缩图片且上传的时候，安卓一切正常，我在开发工具上也一切正常，偏偏ios上就不正常，不正常不是指压缩失败，而是明明也压缩成功了，竟然发不起网络请求，离大谱。因为所有请求的入参都会经过sm2加密，ios压缩成功后想要发起请求，就卡在了加密这步，无法执行下面的请求方法，打印出来加密前的参数也都没问题，但就是卡住了不往下走了，导致压根没发起请求，玄学。更玄的是去年ios都没问题，代码也没动过，现在ios就不行了。经过排查，wx.canvasToTempFilePath加上了两个属性destWidth和destHeight定义又都成功了，奇怪明明是非必填属性，安卓我也没填采用默认的都没问题，说到底我也不确定是不是这个问题，因为也改了其它逻辑，不过现在确实是一切正常了。ios奇奇怪的问题真是太多了，晕。
如今的压缩代码如下（当宽度大于高度时图片可向左旋转）：
wx.createCanvasContext(‘attendCanvasId’)一直提示已废弃，不过以前用了我就不改了，而且改新的也麻烦hhh，主要是也能用：
picCompress(img, width = 600, size = 102, moreCallback) {
let that = this
let imgSize = img.tempFiles[0].size / 1024
console.log('img', img)
let path = img.tempFiles[0].path
console.log('图片大小(kb)', imgSize);
return new Promise((resolve, reject) => {
wx.getImageInfo({
src: img.tempFilePaths[0],
success: function (imgInfo) {
console.log('获取图片信息', imgInfo)
let ctx = wx.createCanvasContext('attendCanvasId');
/**
* 压缩图片：
* 图片宽度大于 width 的时候压缩，小于的时候不操作
*/
if (imgInfo.width > width) {
var canvasWidth = width;
var canvasHeight = (width * imgInfo.height) / imgInfo.width;
//设置canvas尺寸
that.setData({
canvasWidth: canvasWidth,
canvasHeight: canvasHeight
});
//将图片填充在canvas上
if (canvasWidth < canvasHeight) {
//顺时针旋转270度
that.setData({
canvasWidth: (width * imgInfo.height) / imgInfo.width,
canvasHeight: width,
})
console.log('宽高：',canvasWidth,canvasHeight)
ctx.translate(((width * imgInfo.height) / imgInfo.width) / 2, width / 2)
ctx.rotate(270 * Math.PI / 180)
ctx.drawImage(path, -width / 2, -((width * imgInfo.height) / imgInfo.width) / 2, width, (width * imgInfo.height) / imgInfo.width);
}else {
ctx.drawImage(path, 0, 0, canvasWidth, canvasHeight);
}
// ctx.drawImage(path, 0, 0, canvasWidth, canvasHeight);
ctx.draw(false, () => {
//下载canvas图片
//保存临时文件
setTimeout(() => {
wx.canvasToTempFilePath({
canvasId: 'attendCanvasId',
fileType: 'jpg',
quality: 0.5,
/* width: 0,
height: 0, */
destWidth: that.data.canvasWidth,
destHeight: that.data.canvasHeight,
success: function (res) {
console.log(res.tempFilePath)
wx.getImageInfo({
src: res.tempFilePath,
success: function (res) {
console.log('---------------1')
console.log('压缩成功')
console.log(res)
let sourcePhoto = wx.getFileSystemManager().readFileSync(res.path, 'base64')
console.log('------------url:',res.path)
let t = {
tempFilePaths:res.path, picBase64:sourcePhoto}
resolve(t)
}
});
},
fail: function (error) {
console.log(error)
}
})
}, 500)
})
} else if (imgSize > size) {
// 宽度小于width 但是大小大于size 不压尺寸压质量
var canvasWidth = imgInfo.width;
var canvasHeight = imgInfo.height;
//设置canvas尺寸
that.setData({
canvasWidth: canvasWidth,
canvasHeight: canvasHeight
});
//将图片填充在canvas上
if (canvasWidth < canvasHeight) {
//顺时针旋转270度
that.setData({
canvasWidth: (width * imgInfo.height) / imgInfo.width,
canvasHeight: width,
})
ctx.translate(((width * imgInfo.height) / imgInfo.width) / 2, width / 2)
ctx.rotate(270 * Math.PI / 180)
ctx.drawImage(path, -width / 2, -((width * imgInfo.height) / imgInfo.width) / 2, width, (width * imgInfo.height) / imgInfo.width);
}else {
ctx.drawImage(path, 0, 0, canvasWidth, canvasHeight);
}
ctx.draw(false, () => {
setTimeout(() => {
wx.canvasToTempFilePath({
canvasId: 'attendCanvasId',
fileType: 'jpg',
quality: 0.5,
/* width: 0,
height: 0, */
destWidth: that.data.canvasWidth,
destHeight: that.data.canvasHeight,
success: function (res) {
console.log(res.tempFilePath)
wx.getImageInfo({
src: res.tempFilePath,
success: function (res) {
console.log('---------------2')
console.log('压缩成功')
console.log(res)
let sourcePhoto = wx.getFileSystemManager().readFileSync(res.path, 'base64')
console.log('------------url:',res.path)
// moreCallback(res.path, sourcePhoto) tempFilePaths, picBase64
let t = {
tempFilePaths:res.path, picBase64:sourcePhoto}
resolve(t)
}
});
},
fail: function (error) {
console.log(error)
}
})
}, 500)
//下载canvas图片
});
} else {
let canvasWidth = imgInfo.width
let canvasHeight = imgInfo.height
console.log('宽高：',canvasWidth,canvasHeight)
//将图片填充在canvas上
if (canvasWidth < canvasHeight) {
//顺时针旋转270度
that.setData({
canvasWidth: (width * imgInfo.height) / imgInfo.width,
canvasHeight: width,
})
ctx.translate(((width * imgInfo.height) / imgInfo.width) / 2, width / 2)
ctx.rotate(270 * Math.PI / 180)
ctx.drawImage(path, -width / 2, -((width * imgInfo.height) / imgInfo.width) / 2, width, (width * imgInfo.height) / imgInfo.width);
}else {
ctx.drawImage(path, 0, 0, canvasWidth, canvasHeight);
}
ctx.draw(false, () => {
setTimeout(() => {
wx.canvasToTempFilePath({
canvasId: 'attendCanvasId',
fileType: 'jpg',
quality: 0.5,
/* width: 0,
height: 0, */
destWidth: that.data.canvasWidth,
destHeight: that.data.canvasHeight,
success: function (res) {
console.log(res.tempFilePath)
wx.getImageInfo({
src: res.tempFilePath,
success: function (res) {
console.log('---------------3')
console.log('压缩成功')
console.log(res)
let sourcePhoto = wx.getFileSystemManager().readFileSync(res.path, 'base64')
console.log('------------url:',res.path)
// moreCallback(res.path, sourcePhoto) tempFilePaths, picBase64
let t = {
tempFilePaths:res.path, picBase64:sourcePhoto}
resolve(t)
}
});
},
fail: function (error) {
console.log(error)
}
})
}, 500)
});
}
},
fail: function (getInfoErr) {
that.data.loading.clear()
console.log(getInfoErr)
// wx.hideLoading();
wx.showToast({
title: '获取图片信息失败',
icon: 'error',
duration: 2000
});
}
})
})
},
压缩成功后，直接把图片转换成base64，然后直接返回一个promise结果出去，再进行操作后发起请求。
let t = _this.picCompress(res, 600, 100) .then(res => {
// 请求
})
886~
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