Blank screenshots

[marcelblijleven]

What versions are you running?

$ go list -m github.com/chromedp/chromedp
github.com/chromedp/chromedp
$ google-chrome --version
91.0.4472.106
$ go version
go version go1.15.2 darwin/amd64

What did you do? Include clear steps.

func Demo() {
	allocContext, cancel := chromedp.NewExecAllocator(context.Background(), append(
		chromedp.DefaultExecAllocatorOptions[:],
		chromedp.Flag("headless", false),
		chromedp.WindowSize(1920, 1080),
	)...)
	ctx, cancel := browser.NewContext(allocContext)
	defer cancel()

	var tasks chromedp.Tasks
	var buf []byte
	tasks = append(tasks,
		chromedp.Navigate("https://github.com/chromedp"),
		chromedp.Click("[title='chromedp']"),
		chromedp.Screenshot("#readme h1", &buf, chromedp.ByQuery),
	)

	if err := chromedp.Run(ctx, tasks); err != nil {
		panic(err)
	}

	r := bytes.NewReader(buf)
	img, err := png.Decode(r)

	if err != nil {
		panic(err)
	}

	f, err := os.Create("example.png")

	if err != nil {
		panic(err)
	}

	if err = png.Encode(f, img); err != nil {
		panic(err)
	}
}

What did you expect to see?

A screenshot of the h1 inside the README section of the chromedp github actions page

What did you see instead?

A 'blank' screenshot with just the background color. On different websites with a white background, the screenshot will be white

[ZekeLu]

I just sent a PR (#863) to fix some issues of the screenshot actions. Can you confirm whether this issue has been addressed by that PR? Thanks!

[marcelblijleven]

Can confirm your PR fixes the issue! Had to upgrade to Go 1.16 though, but that's no big deal for me

[ZekeLu]

Yes, it uses //go:embed (which was added in Go 1.6) to make it easy to manage the javascript files. The plan is to drop support for Go 1.15 once Go 1.17 is released.
Since there are other isssues tracking the same issue, I'm going to close this one. Thank you!