objects/button.go

package objects

import "git.tebibyte.media/tomo/tomo"
import "git.tebibyte.media/tomo/tomo/theme"
import "git.tebibyte.media/tomo/tomo/input"
import "git.tebibyte.media/tomo/tomo/event"
import "git.tebibyte.media/tomo/objects/layouts"

var buttonLayout     = layouts.NewGrid([]bool { true        }, []bool { true })
var iconButtonLayout = layouts.NewGrid([]bool { false       }, []bool { true })
var bothButtonLayout = layouts.NewGrid([]bool { false, true }, []bool { true })

// Button is a clickable button.
type Button struct {
	tomo.ContainerBox

	label *Label
	icon  *Icon
	labelActive bool
	
	on struct {
		click event.FuncBroadcaster
	}
}

// NewButton creates a new button with the specified text.
func NewButton (text string) *Button {
	box := &Button {
		ContainerBox: tomo.NewContainerBox(),
		label:        NewLabel(text),
	}
	theme.Apply(box, theme.R("objects", "Button", ""))
	box.label.SetAlign(tomo.AlignMiddle, tomo.AlignMiddle)
	box.SetLayout(buttonLayout)
	box.SetText(text)
	
	box.CaptureDND(true)
	box.CaptureMouse(true)
	box.CaptureScroll(true)
	box.CaptureKeyboard(true)
	
	box.OnMouseUp(box.handleMouseUp)
	box.OnKeyUp(box.handleKeyUp)
	box.SetFocusable(true)
	return box
}

// SetText sets the text of the button's label.
func (this *Button) SetText (text string) {
	this.label.SetText(text)
	if this.labelActive && text == "" {
		this.Delete(this.label)
		this.labelActive = false
	}
	if !this.labelActive && text != "" {
		this.Add(this.label)
		this.labelActive = true
	}
	this.applyLayout()
}

// SetIcon sets an icon for this button. Setting the icon to IconUnknown will
// remove it.
func (this *Button) SetIcon (id theme.Icon) {
	if this.icon != nil { this.Delete(this.icon) }

	var icon *Icon; if id != theme.IconUnknown {
		icon = NewIcon(id, theme.IconSizeSmall)
	}
	this.icon = icon

	if this.icon != nil {
		this.Insert(this.icon, this.label)
	}
	this.applyLayout()
}

// OnClick specifies a function to be called when the button is clicked.
func (this *Button) OnClick (callback func ()) event.Cookie {
	return this.on.click.Connect(callback)
}

func (this *Button) applyLayout () {
	if this.labelActive && this.icon == nil {
		this.SetLayout(buttonLayout)
	} else if !this.labelActive && this.icon != nil {
		this.SetLayout(iconButtonLayout)
	} else {
		this.SetLayout(bothButtonLayout)
	}
}

func (this *Button) handleKeyUp (key input.Key, numberPad bool) {
	if key != input.KeyEnter && key != input.Key(' ') { return }
	this.on.click.Broadcast()
}

func (this *Button) handleMouseUp (button input.Button) {
	if button != input.ButtonLeft { return }
	if this.MousePosition().In(this.Bounds()) {
		this.on.click.Broadcast()
	}
}