Bug 58048 - AspectFill behaves differently with Android.FastRenderers.ImageRenderer
Summary: AspectFill behaves differently with Android.FastRenderers.ImageRenderer
Alias: None
Product: Forms
Classification: Xamarin
Component: Android (show other bugs)
Version: 2.3.5
Hardware: PC Mac OS
: --- normal
Target Milestone: ---
Assignee: Bugzilla
Depends on:
Reported: 2017-07-10 14:53 UTC by Matthew Richardson
Modified: 2017-10-05 18:17 UTC (History)
4 users (show)

See Also:
Tags: ac android image stacklayout isclippedtobounds fastrenderer
Is this bug a regression?: Yes
Last known good build:

Screenshot showing XF 2.3.4 vs 2.3.5 (150.67 KB, image/jpeg)
2017-07-10 15:02 UTC, Matthew Richardson
Repro Project XF 2.3.4 (115.93 KB, application/zip)
2017-07-10 15:03 UTC, Matthew Richardson
Repro Project XF 2.3.5 (115.98 KB, application/zip)
2017-07-10 15:03 UTC, Matthew Richardson

Description Matthew Richardson 2017-07-10 14:53:24 UTC
AspectFill behavior is different on XF 2.3.5 vs XF 2.3.4 when using an image in a nested view hierarchy.

Under certain conditions, the image is not cropped correctly to fit the bounds of its container and instead overlaps in the case of multiple images in a vertical layout.

See repro projects XF 2.3.4 vs XF 2.3.5 and screenshot showing difference.
Note: Using IsClippedToBounds="true" on a nested StackLayout in the demo project resolves the problem, but this was not required before XF 2.3.5 and don't want to assume this is a fix (may be a workaround).

Possibly without the parent ViewGroup with the new fast ImageRenderer on Android, the scale behavior has been changed.
Comment 1 Matthew Richardson 2017-07-10 15:02:15 UTC
Created attachment 23451 [details]
Screenshot showing XF 2.3.4 vs 2.3.5
Comment 2 Matthew Richardson 2017-07-10 15:03:18 UTC
Created attachment 23452 [details]
Repro Project XF 2.3.4

Comment 3 Matthew Richardson 2017-07-10 15:03:37 UTC
Created attachment 23453 [details]
Repro Project XF 2.3.5

Comment 4 Jimmy [MSFT] 2017-07-10 21:14:00 UTC
I'm seeing the issue described using the attached repro projects and this does appear to be a regression in 2.3.5.

The images appear to be scaled correctly, they are just not being clipped. As mentioned, using IsClippedToBounds="true" on the inner StackLayout resolves the issue. I tested the same layout replacing the AbsoluteLayout with a RelativeLayout and the issue still occurred.

I also tested the old ImageRenderer and confirmed that the issues does _not_ occur in that case. So another workaround is to use the old renderer by exporting it like a custom renderer:

> [assembly:ExportRenderer(typeof(Xamarin.Forms.Image), typeof(Xamarin.Forms.Platform.Android.ImageRenderer))]

### Version Tests   BAD
2.3.5-pre6  BAD   GOOD
Comment 5 Matthew Richardson 2017-07-11 07:50:45 UTC
Jimmy - I wonder if the clipping behavior was happening implicitly due to the nesting of the image view inside a view group? So 'technically' now it is behaving as expected, but the behavior is not desirable.
Comment 6 Britton Beckham 2017-07-14 19:49:37 UTC
I was getting this same thing, but in a GridLayout. Shouldn't this be considered a breaking change if it is technically correct, even though it was wrong in the first place?

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