my image screenshot in ios webview is occasionally white,

[boboZh]

Bug reports:

my image screenshot in ios webview is occasionally white,
it acts like this "https://img4.easypass.cn/das/carsource1/origin/cac62901-8930-47e3-ac1d-cca42b9e64cc.png",
when add a border to the image, it acts like this, "https://img4.easypass.cn/das/carsource1/origin/d6ea23c2-5f88-44ed-ac74-d2b3c6a73dbd.png"

and here is my code:
Html2Canvas(poster, {
dpi: window.devicePixelRatio * 2,
useCORS: true, // 允许跨域图片
logging: false,
width: width,
height: height,
scale: scale,
canvas: canvas
})
.then(function (canvas) {
let imgBlob = canvas.toDataURL('image/jpg', 1.0)
that._uploadImg(imgBlob)
let shareBase64 = imgBlob.match('data:image/png;base64,') && imgBlob.split('data:image/png;base64,')[1]
that.base64Url = shareBase64
that.$refs.shareWrapper.show(that.shareTextOrigin)

      })
      .catch(err => {
        showToast(this, err.message)
      })

thank you

Specifications:

• html2canvas version tested with: "^1.0.0-rc.3"
• Browser & version: ios webview
• Operating system: ios

[icksky]

the same. try to transform the source image's src to base64, then use html2canvas to generate your image.
I debug the html2canvas, and found out that the image's complete is false, but never dispatch load event. So the intrinsicWidth and intrinsicHeight is 0 when new ImageElementContainer.
I don't know if this cause the bug. Hope a little help.

[boboZh]

the same. try to transform the source image's src to base64, then use html2canvas to generate your image.
I debug the html2canvas, and found out that the image's complete is false, but never dispatch load event. So the intrinsicWidth and intrinsicHeight is 0 when new ImageElementContainer.
I don't know if this cause the bug. Hope a little help.

awsome! it works! thanks a lot!

[Viin-zx]

兄台，请问下如何处理的在ios手机下渲染白屏问题。有点没理解。

[boboZh]

兄台，请问下如何处理的在ios手机下渲染白屏问题。有点没理解。

我的问题是渲染没毛病，但是截图有毛病，上面这位sky网友的意思是你把图片地址转为base64再放上去，试一下看行不行，我的OK

[Viin-zx]

@boboZh 哥，请教下您知道为什么在ios上渲染不出来dom中的图片么，概率性事件，概率还挺大的。web和安卓都没问题。找了几天都没找到解决方法。

[boboZh]

@boboZh 哥，请教下您知道为什么在ios上渲染不出来dom中的图片么，概率性事件，概率还挺大的。web和安卓都没问题。找了几天都没找到解决方法。

这个不清楚诶，没有遇到过

[the-natty]

@boboZh 哥，请教下您知道为什么在ios上渲染不出来dom中的图片么，概率性事件，概率还挺大的。web和安卓都没问题。找了几天都没找到解决方法。

the same problem!

[boboZh]

the same. try to transform the source image's src to base64, then use html2canvas to generate your image.
I debug the html2canvas, and found out that the image's complete is false, but never dispatch load event. So the intrinsicWidth and intrinsicHeight is 0 when new ImageElementContainer.
I don't know if this cause the bug. Hope a little help.

but now, it can reproduce occassionally with base64 src, do you know how to do with this?

[icksky]

but now, it can reproduce occassionally with base64 src, do you know how to do with this?

I also found out this, but sorry, I have no idea too.

[mliotinoca]

Increasing imageTimeout value don't solve it completely.
Issue happens randomly anyway, I think on heavy images, even in base64.
I have solved by this #2344

[wenlittleoil]

2023, the problem still exist in some iphone.