Vertical and Horizontal space around the text are used additional values

[XFRAY]

As I see you use some additional values to measure vertical and horizontal padding

val verticalSpaceAroundText = (textHeight * .12f + 6 + paddingVertical).toInt()

What is 6 and .12 here ?

Same for
val horizontalSpaceAroundText = ((textHeight * .24f) + 8 + paddingHorizontal).toInt()

What is 8 and .24 here ?

[SmartToolFactory]

Those are the base values to use when fontSize, or text height, is too small. 24% or 12% of small text height values doesn't look good. You can test it out by removing static values and use 12.sp or less. If you can come up with better formula for paddings for any size of text or paddings, feel free to open a PR.

[XFRAY]

6 and 8 are used also by that reason ?

[SmartToolFactory]

Yes, but i think it would be better to changed them with Float.coerceAtLeast as ((textHeight * .12f).coerceAtLeast(Some number) + paddingVertical).toInt() would be better

[XFRAY]

I looked into this and your "magic" values would work only with default Android fonts.
During testing it I figured out that would be better to use
val textHeight = (paint.fontFetrics.bottom - paint.fontFetrics.top)

Then val verticalSpaceAroundText = textHight - textSize
Then we need to calculate horizontalSpace to make background a circle if text.lenght == 1 otherwise rect

val paddedTextWidth = (textWidth + spaceAroundText * 2 + paddingStart + paddingEnd).toInt()
val desiredHeight = (textHeight + spaceAroundText + paddingTop + paddingBottom).toInt()
val desiredWidth = paddedTextWidth.coerceAtLeast(desiredHeight)

I used all space as a left and right padding to expand a rect
otherwise it will be smaller then circle shape when there is text.length == 2