Only use custom image sizing with ImageButtons

[jknaudt21]

Problem

Updates on the image resizing #17120 affected normal buttons with images, causing them to call the custom image sizing logic. The updates made images to occupy the space they are provided in respect to their constraints. This fixed ImageButton and Image but adversely affected Button.

Standard Buttons don't have control over their image dimensions, but do have control on how they want to lay these images out them out. Calling the new logic removes this functionality and causes buttons to occupy their available space/occupy the space requested by the image (which would ignore the text in the button).

Solution

Use the old sizing logic with normal Buttons but still use the new sizing logic for ImageButton. We can differentiate them based on the value of the native view's CurrentTitle. ImageButtons can't have text and have a null value for CurrentTitle, so we add this check before using the image resizing logic.

Note: Even if a Button has no Text value (or its ""), the native control will have a non-null CurrentTitle that'll just be the empty string. This is included in the tests I'm adding

Before & After

18504 (click me!)

    <Grid WidthRequest="500" BackgroundColor="Red">
        <Button HorizontalOptions="Center" VerticalOptions="Center" BackgroundColor="AliceBlue" ImageSource="dotnet_bot.png" Text="Hello world!"/>
    </Grid>

Before	After

18655 (click me!)

Copy source from sample project: https://github.com/zwikk/maui-playground/blob/main/Source/ButtonImageSource/ButtonImageSource/MainPage.xaml

Before	After

Issues Fixed

Fixes #18504
Fixes #18655

Remaining work

• Add tests
• Add screenshots