Improve UIScreen Capture() support for complex views

[christianhelle]

The current UIScreen Capture() method doesn't support complex views with multiple CA Layers (for example iCarousel). The changes here are in use in our apps in the AppStore with over half a million daily active users and no one has ever reported a bug regarding it. I kept the original code for backward compatibility as drawViewHierarchyInRect:afterScreenUpdates: was introduced in iOS 7.0. My changes were based from https://developer.apple.com/library/content/qa/qa1817/_index.html

Screenshot using original Capture() implementation:

Screenshot using the changes in this pull request:

The images above are from an app with a screen using iCarousel with 8 items containing both images and texts. I used the UIScreen Capture() method to capture this screen before opening another screen where I show it as the background image.

I unfortunately had to crop out the rest of the image due to corporate reasons, but the images provided above are enough to illustrate the problem. I can provide a video of the problem if needed as long as this video is not shared with the general public

[dnfclas]

Hi @christianhelle, I'm your friendly neighborhood .NET Foundation Pull Request Bot (You can call me DNFBOT). Thanks for your contribution!

This seems like a small (but important) contribution, so no Contribution License Agreement is required at this point. Real humans will now evaluate your PR.

TTYL, DNFBOT;

[monojenkins]

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[rolfbjarne]

approve

[rolfbjarne]

I think this looks good, except for a minor style issue: we use a space before the opening parenthesis in a method call. Could you please fix this (you've also changed it in the existing code you've re-indented due to the additional if clause)?

Also I don't think there are any backwards compatibility issues, and the new code is clearly rendering a better screenshot according to the provided screenshots.

[christianhelle]

Thanks for the input @rolfbjarne, I'll fix the styling issue you pointed out.

I'm pretty sure that the method drawViewHierarchyInRect:afterScreenUpdates: was introduced in iOS 7.0 since it states that in the documentation page. If I didn't include the original implementation then calling Capture() would fail on older iOS versions.

I'm fine with replacing the old implementation but I wanted to tread carefully since this is my first time contributing to the product I thought I should consider backwards compatibility

[spouliot]

👍 (modulo Rolf's comments)
Thanks for your contribution!

[monojenkins]

Build failure

[christianhelle]

I updated my changes based on the comments by @rolfbjarne

[monojenkins]

Build failure

[rolfbjarne]

Test failures are unrelated (watchOS/System test failures filed as bug #47167).

[rolfbjarne]

Thanks!

[mandel-macaque]

Looking at this PR, we should also test that the UIView.Capture added in commit 7c51c3b

@rolfbjarne what do you think?
@christianhelle do you have an example I could use for testing?

[mandel-macaque]

/cc @spouliot I forgot you ;)