Tooltip

Tooltip shows a tip once the pointer rests on an element, or the keyboard focus comes to it, and describes the element to assistive technology:

ui.Button(c, "").Label("Share").Tooltip("Share with others").Children(func() {
	ui.Icon(c, share)
})

The tip shows once the pointer has rested on the element for 0.6 seconds, and at once as the keyboard focus comes to it from the keyboard. It goes above the element, centered, or below it where there is no room above, wherever the pointer is on the element, as Base UI's does. Within 0.4 seconds of a tip going, the next one shows at once, as the pointer moves along a toolbar. It goes as the pointer leaves, and a press or a click on the element, or Escape, hides it until the pointer leaves and comes back, or the focus does: it does not show again after a click, nor beside the menu a menu button opens. Over elements inside one another, the innermost one's tip shows, and one tip shows at a time. Give one to buttons showing only an icon, and to what a label alone does not explain.

The focus counts for the element an element gives it to, its ActiveDescendant, as a menu drawn in the window gives it to the item the keys highlight: that one's tip shows.

The tip takes the theme's Inverse and InverseText colors, its text and background turned over unless the theme sets them (see themes).

The delay

The theme's TooltipDelay sets how long the pointer rests on an element before its tip shows, for Tooltip and TooltipBase alike: 0 is 0.6 seconds, and a negative delay shows the tip at once. The time within which the next tip shows at once follows it, two thirds of it (0.4 seconds by default). A dense settings page shows its tips sooner, and a toolbar of many small buttons, or a page that also shows help inline, later:

t := *c.Theme()
t.TooltipDelay = 300 * time.Millisecond
c.SetTheme(&t)

For a part of the window only, as a toolbar, build it in ui.Themed with that theme (see a theme for part of the window); each element's tip waits as the theme it is built with says.

Without a look

TooltipBase shows a tip of your own by an element, as Base UI's Tooltip does: it decides when the tip shows and goes, as above, and fn styles the tip and builds its content. The tip goes above the element, centered, or below it where there is no room above; place it elsewhere with AttachTo, its margins keeping it apart from the element. AttachedAnchors tells the side it went to, and AttachedOrigin scales it from the edge nearest the element (see overlays):

b := ui.Button(c, "").Label("Share").Description("Share with others")
b.Children(func() { ui.Icon(c, share) })
ui.TooltipBase(c, b, func(tip ui.Element) {
	tip.AttachTo(b, ui.AnchorRight, ui.AnchorLeft).Margin(0, 0, 0, 6)
	tip.Padding(4, 8).Radius(6).Background(ink).TextColor(paper)
	tip.Children(func() {
		ui.Text(c, "Share with others")
		ui.Text(c, "⌘S").TextColor(muted)
	})
})

It returns the tip, or nil while it does not show. The pointer goes through the tip.

Accessibility

Assistive technology reads the tip of Tooltip as the element's description, after its name, as help text, unless Description gives another. It sees the tip of TooltipBase as a tooltip, which it does not read: give the element a Description telling what the tip does.