Icon

ui.Icon shows an SVG as an icon: in the color of the text, which it takes from its ancestors as text does, whatever colors the file has, and as high as the font size, keeping the SVG's aspect ratio. Icon sets such as Lucide, Heroicons, Tabler or Material Symbols work as they are:

//go:embed icons/save.svg
var saveSVG []byte

var save = ui.MustParseSVG(saveSVG)

ui.Row(c).Gap(6).Children(func() {
	ui.Icon(c, save)
	ui.Text(c, "Save")
})
ui.Icon(c, save).FontSize(24).TextColor(c.Theme().Danger)

FontSize and TextColor size and color it, as they do text; Size gives it another size. An icon does not stretch across a column.

In buttons

Inside a button, which lays out its children in a row and gives them its text color, an icon goes before the label:

ui.PrimaryButton(c, "").Children(func() {
	ui.Icon(c, save)
	ui.Text(c, "Save").SingleLine()
})

Rotate turns an icon, as a spinner or an arrow that opens:

spin := ui.Icon(c, loader)
spin.Rotate(spin.Loop("spin", time.Second, ui.Linear) * 360)

How MyGo draws SVGs, and what of them it draws, is on the Image page. In Draw callbacks, Painter.Icon draws an icon.

Accessibility

Icons are decorations that assistive technology does not see, unless Label names them: name a button showing only an icon instead.