Shadows disappearing permanently in Android and Windows after Label opacity is at any time set to "0"

[jonmdev]

Description

Bug Behavior:

Shadows on Labels disappear after the Label is set to 0 opacity and do not return.

Affected Platforms:

Windows for ~2 years. Now Android too (regression). Did not test iOS.

Details

I reported almost two years ago this bug in Windows: #17916

This issue has not received any attention since, although it was verified by staff, from my minimal reproduction project.

The problem persists but now has also spread to Android. Previously this was not a problem in Android, only Windows. Now I see this problem in my Android builds as well. I am not sure how long it has been there but it certainly wasn't a problem from the beginning.

@albyrock87 and @jsuarezruiz I know you did a lot to optimize shadows, and I am grateful for that. Any thoughts?

Here is a new Bug Project reproducing the issue in certainly at least both Windows and Android (iOS not tested): https://github.com/jonmdev/ShadowVisibilityBug

REPRODUCTION CODE

My project reproduces the bug in a blank Maui default project, with the following added to App.xaml.cs:

public class MyMainPage : ContentPage {
    public MyMainPage() {
        
        // Basic page build 
        AbsoluteLayout abs = new();
        Content = abs;

        AbsoluteLayout tweenAbs = new();
        abs.Add(tweenAbs);

        Label label = new();
        label.Text = "HELLO";
        label.FontSize = 80;
        label.Shadow = new() { Brush = Colors.DarkRed, Radius = 10, Offset = new Point(0, 4) };
        tweenAbs.Add(label);

        //========================
        // BUG INSTRUCTIONS
        //========================
        // 1) Set veToTween = label
        // 2) Set toggleVisibility = false (don't toggle visibility)
        // 3) See no shadow on Android or Windows as the label tweens in
        // 4) Set toggleVisibility = true to recover shadow on Android, but not Windows
        //========================

        // Create Timer
        var timer = Application.Current.Dispatcher.CreateTimer();
        double deltaTime = 1 / 60.0;
        double fadeDuration = 5;
        VisualElement veToTween = label;
        veToTween.Opacity = 0;
        
        // TOGGLE "IS VISIBLE" TRICK
        bool toggleVisibility = false; // "true" recovers the android shadow, but still not windows
        if (toggleVisibility) { veToTween.IsVisible = false; }
        
        // Timer Animation Tick
        timer.Tick += delegate (object s, EventArgs e) {

            // toggling the "IsVisible" seems to recover the android shadow but not the Windows one
            if (toggleVisibility) {
                veToTween.IsVisible = true; 
            }

            // tween up the opacity until it hits 1
            if (veToTween.Opacity < 1) {
                veToTween.Opacity += deltaTime / fadeDuration;
            }
            if (veToTween.Opacity > 1) {
                veToTween.Opacity = 1;
            }
        };
        timer.Interval = TimeSpan.FromSeconds(deltaTime);
        timer.Start();

    }
}

You can see this is just a simple animation on a Label that has a shadow to tween opacity 0 to 1.

In both cases (Android and Windows), there is no shadow visible on the Label. Previously this was known in Windows, but as noted it is now new in Android.

Interestingly, in Android, we can recover the shadow by setting toggleVisibility = true in my code. This switches Label visibility off and then on. I don't know what this signifies or why this helps. I was just trying to find any way to make it work.

Steps to Reproduce

1. Open my project
2. See all code is in App.xaml.cs
3. Run the project, it will tween in a label that should have a shadow on it.
4. There will be no shadow on Android or Windows visible though.

Link to public reproduction project repository

https://github.com/jonmdev/ShadowVisibilityBug

Version with bug

9.0.14 SR1.4

Is this a regression from previous behavior?

Yes, this used to work in .NET MAUI

Last version that worked well

Unknown/Other

Affected platforms

Windows, Android

Affected platform versions

[similar-issues-ai]

We've found some similar issues:

• Shadow on Label disappears permanently and won't come back if Label opacity is ever tweened down to zero #17916 , similarity score: 87%
• Shadows not drawing/updating correctly in Windows & cover entire screen (okay in Android/iOS) #18172 , similarity score: 84%
• Shadows not working on Windows #8150 , similarity score: 82%
• MAUI is not correctly drawing or updating shadows causing bizarre outcomes in numerous situations in Windows (simple repro project included) #17996 , similarity score: 82%
• Shadow not displaying properly in Border #13944 , similarity score: 81%

If any of the above are duplicates, please consider closing this issue out and adding additional context in the original issue.

Note: You can give me feedback by 👍 or 👎 this comment.

[jsuarezruiz]

/triage

[github-actions]

Triage Summary

Labels will be applied to indicate the issue affects the Label control and falls under drawing functionality, and also identify the affected platforms (Windows and Android). Additionally, this issue is flagged as a potential regression due to its behavior changing on Android.

This issue is a regression on Android, as shadows on labels were previously functional and now fail to reappear when opacity is set to 0.

Detailed Summary and Actions

Summary of the triage:

• The issue is specific to the Label control, as it involves shadows disappearing and not returning when opacity is set to 0.
• The issue falls under the drawing category due to its relation to shadow rendering.
• The issue affects both Android and Windows platforms, with the problem on Windows being longstanding (about two years) and newly observed as a regression on Android.
• The regression is marked as "potential-regression" because the behavior previously worked correctly on Android but has now become problematic.

Summary of the actions that will be performed:

Action	Item	Description
Apply Label	area-controls-label	The issue specifically targets the Label control, focusing on shadow behavior when opacity is adjusted.
Apply Label	area-drawing	Since the issue is related to shadow rendering, it falls under the category of drawing functionality as well.
Apply Label	platform/android	The regression and current behavior specifically affect Android as detailed in the report.
Apply Label	platform/windows	The issue has also affected Windows for an extended period, as described by the reporter.
Apply Label	potential-regression	The issue is identified as a regression on Android due to its change in behavior from working correctly to failing.

This entire triage process was automated by AI and mistakes may have been made. Please let us know so we can continue to improve.

[deepika2509]

This issue has been verified in Visual Studio 17.14.0 Preview 4.0 for windows and Visual Studio Code 1.99.3 with MAUI versions (9.0.0, 9.0.70 & 8.0.100). It can be reproduced on Windows and Android platform.