[Bug] Brushes API - z draw order on Android is incorrect in certain cases

[Tommigun1980]

I draw a frame with a shadow color, then a box with a gradient brush, and then a font image on top.

This is how it should look:

The following problem happens on Android, on iOS the draw order is correct (The fill direction changes because I was playing around with it, that is not a bug):

1. If the frame has a shadow and a transparent background, it gets drawn on top of the box view (or any element) that has a brush background, even though the brush has a higher z value:

2. Turning off the frame's shadow restores proper draw order:

3. I managed to hack it to work by setting the frame's background's alpha to 1, and keep the shadow on:

                    <Grid
                        <Frame Style="{StaticResource MyShadowFrameStyle}" />
                        <BoxView Style="{StaticResource MyGradientBoxStyle}" />
                        <Button
                            Style="{StaticResource MyTransparentFontIconButtonStyle}"
                            Text="{x:Static local:MyFontIcons.Plus}" />
                    </Grid>

[jsuarezruiz]

Mnn, not sure if I replicated exactly the same UI. I am using a Frame with a transparent Background and shadow enabled. Then, a BoxView where I applied the gradient and finally a transparent button.

The result is:

Cannot reproduce the issue. @Tommigun1980 Could you attach a reproduction sample?. Thanks in advanced.

[Tommigun1980]

I had a frame at the bottom with a shadow (for reasons unrelated to this), then a box view with the brush, and then a button with a font image. I’ll try to find time to wrap that in a repro project but maybe you could quickly add the missing component? Thanks!

…

On Monday, August 10, 2020, Javier Suárez ***@***.***> wrote: Mnn, not sure if I replicated exactly the same UI. I am using a Frame with a transparent Background and shadow enabled. Then, a BoxView where I applied the gradient and finally a transparent button. The result is: [image: Captura de pantalla 2020-08-10 a las 16 00 10] <https://user-images.githubusercontent.com/6755973/89791206-4408ff00-db23-11ea-817c-fb07a8f62379.png> Cannot reproduce the issue. @Tommigun1980 <https://github.com/Tommigun1980> Could you attach a reproduction sample?. Thanks in advanced. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#11714 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AOL6P6DS6UU4MLU2LB6ANW3R775D5ANCNFSM4PZDDREA> .

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[jsuarezruiz]

@Tommigun1980 Tried but cannot reproduce the Z-Index issue. Could you take a look to: https://github.com/xamarin/Xamarin.Forms/blob/fix-11714/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue11714.xaml?
Do we do something differently?