InlayModel addAfterLineEndElement

I want to add some text after the caret. I found that InlayModel.addAfterLineEndElement may be the API I need. I wrote the below code, but the position of added text is strange.

val caret = editor.caretModel
val lineEnd = caret.visualLineEnd
val inlayModel = editor.inlayModel
inlayModel.addAfterLineEndElement(lineEnd, true, object : EditorCustomElementRenderer {
    override fun getContextMenuGroupId(inlay: Inlay<*>): String? {
        return null
    }

    override fun calcWidthInPixels(inlay: Inlay<*>): Int {
        return (JBUI.pixScale(inlay.editor.component) * 11).roundToInt()
    }

    override fun paint(inlay: Inlay<*>, g: Graphics, targetRegion: Rectangle, textAttributes: TextAttributes) {
        g.color = JBColor.GRAY
        g.drawString("Hello world", targetRegion.x,
                targetRegion.y)
    }
})

Below is the running example. The `Hello world` is added after I typed I.

I tried different positon for the g.drawString function but no one works.

So what is the coordinate system of the `g` parameter in the paint function? And how should I get the x and y

for the g.drawString function so that I can add the `Hello world` after `I`?