在中心的椭圆形路径上绘制文本

Question

I'm trying to draw some text on path using the canvas in Android. I can successfully get the text to draw on the top oval line. What i'm struggling to do is make sure that the text is centered.

The problem is that while i can measure the text before it gets drawn round the top line of the oval, i cannot measure it after. This makes estimating where the text should be drawn on the top oval line problematic as it's always a little bit out. This is because when i measure the text to be drawn initially it is measured in a straight line and not as presented on the top line of the oval.

I've tried applying setTextAlign(Paint.Align.CENTER) but this makes the text get drawn about 3/4's of the way round and not what i want.

Does anyone have any ideas how i could calculate the point to draw the text so it is drawn dead centre of the top oval line or any alternative method that may help?

This has to be drawn using the canvas. It can't be done using XML TextViews etc.

Thanks.

Answer 1

You can check how this library done it: https://github.com/amulyakhare/TextDrawable

Its using the same approach. But for multiple lines its almost impossible, theres an issue on this library where me and other developers tried to implement it, and we end up using just xml (a round drawable as a linearLayout view background and one textView inside it).