Button

widget.Button is a focusable action trigger. It fires a callback when the user presses Enter or Space.

All built-in themes set Border: BorderSingle and RoundedCorner: true on the Button token, so buttons automatically render with rounded arc corners:

╭────────╮
│  Save  │
╰────────╯

Basic usage

btn := widget.NewButton("Save", func() {
    // handle the press
})

Builder options

Method	Description
WithStyle(s latte.Style)	Override the display style
WithID(id string)	Set a stable identifier for Canvas.GetValue(id)
WithRoundedCorner(bool)	Explicitly enable or disable arc corners (╭╮╰╯)

Border and height

Button.Measure derives border presence from b.Style (the unfocused base style) only — focus state never affects the layout shape.

b.Style.Border	Measure height	Rendered as
BorderSingle (theme default)	3 rows	bordered box
BorderRounded	3 rows	bordered box with arc corners
BorderNone / BorderExplicitNone	1 row	[ label ] inline

FocusStyle / ButtonFocus carry only colour and attribute overrides (Reverse: true, accent BorderFG). The layout shape is stable regardless of focus state — a button row in a dialog always measures the same height whether or not a button inside it has focus.

WithStyle

btn := widget.NewButton("Danger", onDelete).
    WithStyle(latte.Style{FG: latte.ColorRed, Bold: true})

The theme supplies focus colours on top of whatever style you set. Use WithStyle to control the unfocused appearance only.

WithRoundedCorner

// Explicit opt-in — overrides the theme's RoundedCorner setting for this button.
btn := widget.NewButton("OK", fn).
    WithRoundedCorner(true)

// Explicit opt-out — disables arc corners even when the active theme has RoundedCorner: true.
btn := widget.NewButton("Cancel", fn).
    WithRoundedCorner(false)

• true — draws arc corners (╭╮╰╯) instead of square ones (┌┐└┘).
• false — disables arc corners regardless of the theme's RoundedCorner setting.
• Once called, this explicit choice overrides the theme for this button. Buttons that never call WithRoundedCorner inherit the theme's RoundedCorner value automatically via ApplyTheme.
• If the button's resolved border style is incompatible with arc corners (BorderDouble, BorderThick, BorderDashed), the rounded-corner request is a silent no-op — the button keeps its original square corners without panicking.

// Silent no-op example — dashed border stays square, no panic.
btn := widget.NewButton("Dashed", fn).
    WithStyle(latte.Style{Border: latte.BorderDashed}).
    WithRoundedCorner(true)  // silently ignored; dashed stays square

tip

Because all built-in themes set RoundedCorner: true, you do not need to call WithRoundedCorner(true) on every button — it happens automatically when a theme is applied. Only call it explicitly when you want to override the theme's default.

With an ID

Assign an ID to retrieve the button's label later via Canvas.GetValue(id):

btn := widget.NewButton("Delete", onDelete).WithID("delete-btn")

In a button row

The typical pattern is an HBox with HFill to push buttons to the right:

btnRow := layout.NewHBox()
btnRow.AddChild(layout.NewHFill())              // pushes buttons rightward
btnRow.AddChild(cancelBtn)
btnRow.AddChild(layout.NewHFill().WithMaxSize(2)) // 2-cell gap between buttons
btnRow.AddChild(okBtn)

Because buttons always measure Height: 3 (with the default bordered theme), a dialog body containing a button row needs at least 3 rows allocated for that row. Account for this when sizing dialogs with WithMaxSize.

Reading the value

Button implements oat.ValueGetter. Canvas.GetValue(id) returns the button's label as a string.

Keyboard behavior

Key	Action
Enter	Fires the press callback
Space	Fires the press callback
Tab / Shift+Tab	Move focus to next / previous widget