[BUG] Opposite card side visible on large displays

[fenjalien]

Expected Behavior

The opposite card side should not be visible on any sized display.

Current Behavior

When viewing a FlipCard (on a Windows device) on my monitor (2560x1440) a vertical line of a few pixels across is visible. I believe this is the other side of the card.

A close up:

Possible Solution

I think this is due to the scaling applied by the Transform widget here:

flip_card/lib/flip_card.dart

Line 32 in 78a17a7

transform.setEntry(3, 2, 0.001);

A scaling of 0.001 * 2500 would give about 3 pixels depending on rounding.
A solution that I found to work was changing the number to 0.0001, where the vertical line disappeared. This isn't a perfect solution, merely delaying the problem until 10,000+ pixel wide screens become commonly used.

Steps to Reproduce

1. Create a FlipCard that is about 2000 pixels wide.

Context (Environment)

[flutter] flutter doctor -v
[√] Flutter (Channel stable, 3.7.9, on Microsoft Windows [Version 10.0.19044.2728], locale en-GB)
    • Flutter version 3.7.9 on channel stable at C:\Users\fenjalien\code\flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 62bd79521d (10 days ago), 2023-03-30 10:59:36 -0700
    • Engine revision ec975089ac
    • Dart version 2.19.6
    • DevTools version 2.20.1

[√] Windows Version (Installed version of Windows is version 10 or higher)

[!] Android toolchain - develop for Android devices (Android SDK version 32.1.0-rc1)
    • Android SDK at C:\Users\fenjalien\AppData\Local\Android\sdk
    • Platform android-33, build-tools 32.1.0-rc1
    • Java binary at: C:\Program Files\Android\Android Studio\jre\bin\java
    • Java version OpenJDK Runtime Environment (build 11.0.11+9-b60-7590822)
    ! Some Android licenses not accepted. To resolve this, run: flutter doctor --android-licenses

[√] Chrome - develop for the web
    • Chrome at C:\Program Files\Google\Chrome\Application\chrome.exe

[√] Visual Studio - develop for Windows (Visual Studio Community 2019 16.11.5)
    • Visual Studio at C:\Program Files (x86)\Microsoft Visual Studio\2019\Community
    • Visual Studio Community 2019 version 16.11.31729.503
    • Windows 10 SDK version 10.0.19041.0

[√] Android Studio (version 2021.1)
    • Android Studio at C:\Program Files\Android\Android Studio
    • Flutter plugin can be installed from:
       https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
       https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 11.0.11+9-b60-7590822)

[√] VS Code (version 1.77.1)
    • VS Code at C:\Users\fenjalien\AppData\Local\Programs\Microsoft VS Code
    • Flutter extension version 3.62.0

[√] Connected device (4 available)
    • EB2103 (mobile)   • 4c5764b8 • android-arm64  • Android 12 (API 31)
    • Windows (desktop) • windows  • windows-x64    • Microsoft Windows [Version 10.0.19044.2728]
    • Chrome (web)      • chrome   • web-javascript • Google Chrome 111.0.5563.65
    • Edge (web)        • edge     • web-javascript • Microsoft Edge 111.0.1661.44

[√] HTTP Host Availability
    • All required HTTP hosts are available

! Doctor found issues in 1 category.

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This may be related to #73

[ciriousjoker]

@fenjalien Feel free to open a PR to change this. The change sounds reasonable with low potential to break anything.