Background color alpha overlap at bottom

[drewbitt]

Errors in both light and dark mode
new-parser branch

Code:

Html(data: 'Test',
    style: {
      'html': Style(backgroundColor: Colors.black.withAlpha(80))
    });

Most colors .withAlpha have this issue

[DFelten]

Same issue here. It's not possible to define an alpha value or opacity for colors for attributes within the html content.

[tneotia]

I looked into this - it's happening because the colors are getting compounded:

When there are multiple items with the same background color on top of each other, and they have some transparency, Flutter is going to render the intersection of those items darker than the original color.

I'm going to see if there's a way to prevent this if this behavior is not in line with HTML spec.

Edit: I found which widget is causing this, its the TextSpan widget, which accepts backgroundColor in its style. However, this behavior is in line with HTML spec:

With this in mind, I don't know if we should try to fix this, it could prove an issue when others want this behavior. What are your thoughts @erickok ?

[Sub6Resources]

Closing, since this is expected behavior