doodle/lib/ui/functions.go

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package ui
import "git.kirsle.net/go/render"
// AbsolutePosition computes a widget's absolute X,Y position on the
// window on screen by crawling its parent widget tree.
func AbsolutePosition(w Widget) render.Point {
abs := w.Point()
var (
node = w
ok bool
)
for {
node, ok = node.Parent()
if !ok { // reached the top of the tree
return abs
}
abs.Add(node.Point())
}
}
// AbsoluteRect returns a Rect() offset with the absolute position.
func AbsoluteRect(w Widget) render.Rect {
var (
P = AbsolutePosition(w)
R = w.Rect()
)
return render.Rect{
X: P.X,
Y: P.Y,
W: R.W + P.X,
H: R.H, // TODO: the Canvas in EditMode lets you draw pixels
// below the status bar if we do `+ R.Y` here.
}
}