I have a figma design like this
Figma Design and confused how to achieve this.

So I’ve already try using custom painter & 9 patch using this library https://pub.dev/packages/ninepatch_image but not quite the result I want.

The result when I use CustomPainter look like this:

and 9 patch look like this:

…while this result is better than the CustomPainter but I need the yellow Container to be fill the parent container

Any help will be appreciated. Thanks