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. // X and Y are the AbsolutePosition of the widget. // W and H are the widget's width and height. (X,Y not added to them) 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, H: R.H, // TODO: the Canvas in EditMode lets you draw pixels // below the status bar if we do `+ R.Y` here. } } // HasParent returns whether the target widget is a descendant of the parent. // This scans the parents of the widget recursively until it finds a match. func HasParent(w Widget, parent Widget) bool { next, ok := w.Parent() for ok { if next == parent { return true } next, ok = next.Parent() } return false } // widgetInFocusedWindow returns whether a widget (like a Button) is a // descendant of a Window that is being Window Managed by Supervisor, and // said window is in a Focused state. // // This is used by Supervisor to decide whether the widget should be given // events or not: a widget in a non-focused window ignores events, so that a // button in a "lower" window could not be clicked through a "higher" window // that overlaps it. func widgetInFocusedWindow(w Widget) (isManaged, isFocused bool) { var node = w for { // Is the node a Window? if window, ok := node.(*Window); ok { return window.managed, window.Focused() } node, _ = node.Parent() if node == nil { return false, true // reached the root } } }