83 lines
2.0 KiB
Go
83 lines
2.0 KiB
Go
package ui
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import (
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"git.kirsle.net/go/render"
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)
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// AbsolutePosition computes a widget's absolute X,Y position on the
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// window on screen by crawling its parent widget tree.
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func AbsolutePosition(w Widget) render.Point {
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abs := w.Point()
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var (
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node = w
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ok bool
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pt render.Point
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)
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for {
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node, ok = node.Parent()
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if !ok { // reached the top of the tree
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return abs
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}
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pt = node.Point()
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pt.Add(render.NewPoint(node.BorderSize(), node.BorderSize()))
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abs.Add(pt)
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}
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}
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// AbsoluteRect returns a Rect() offset with the absolute position.
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// X and Y are the AbsolutePosition of the widget.
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// W and H are the widget's width and height. (X,Y not added to them)
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func AbsoluteRect(w Widget) render.Rect {
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var (
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P = AbsolutePosition(w)
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R = w.Rect()
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)
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return render.Rect{
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X: P.X,
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Y: P.Y,
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W: R.W,
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H: R.H, // TODO: the Canvas in EditMode lets you draw pixels
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// below the status bar if we do `+ R.Y` here.
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}
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}
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// HasParent returns whether the target widget is a descendant of the parent.
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// This scans the parents of the widget recursively until it finds a match.
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func HasParent(w Widget, parent Widget) bool {
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next, ok := w.Parent()
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for ok {
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if next == parent {
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return true
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}
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next, ok = next.Parent()
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}
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return false
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}
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// widgetInFocusedWindow returns whether a widget (like a Button) is a
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// descendant of a Window that is being Window Managed by Supervisor, and
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// said window is in a Focused state.
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//
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// This is used by Supervisor to decide whether the widget should be given
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// events or not: a widget in a non-focused window ignores events, so that a
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// button in a "lower" window could not be clicked through a "higher" window
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// that overlaps it.
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func widgetInFocusedWindow(w Widget) (isManaged, isFocused bool) {
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var node = w
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for {
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// Is the node a Window?
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if window, ok := node.(*Window); ok {
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return window.managed, window.Focused()
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}
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node, _ = node.Parent()
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if node == nil {
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return false, true // reached the root
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}
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}
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}
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