clui/checkbox.go

package clui

import (
	term "github.com/nsf/termbox-go"
)

/*
CheckBox control. It can be two-state one(on and off) - it is default mode - or tree-state.
State values are 0=off, 1=on, 2=third state
Minimal width of a checkbox cannot be less than 3
Own methods:
Allow3State, SetAllow3State, State, SetState
*/
type CheckBox struct {
	ControlBase
	state       int // 0 - off, 1 - on, 2 - third state(?)
	allow3state bool
}

func NewCheckBox(view View, parent Control, width int, title string, scale int) *CheckBox {
	c := new(CheckBox)
	c.view = view
	c.parent = parent

	c.SetSize(width, 1) // TODO: only one line checkboxes are supported at that moment
	c.SetConstraints(width, 1)
	c.state = 0
	c.SetTitle(title)
	c.SetTabStop(true)
	c.allow3state = false

	if parent != nil {
		parent.AddChild(c, scale)
	}

	return c
}

func (c *CheckBox) Repaint() {
	x, y := c.Pos()
	w, h := c.Size()
	canvas := c.view.Canvas()
	tm := c.view.Screen().Theme()

	fg, bg := RealColor(tm, c.fg, ColorControlText), RealColor(tm, c.bg, ColorControlBack)
	if !c.Enabled() {
		fg, bg = RealColor(tm, c.fg, ColorControlDisabledText), RealColor(tm, c.bg, ColorControlDisabledBack)
	} else if c.Active() {
		fg, bg = RealColor(tm, c.fg, ColorControlActiveText), RealColor(tm, c.bg, ColorControlActiveBack)
	}

	parts := []rune(tm.SysObject(ObjCheckBox))

	cOpen, cClose, cCheck, cEmpty, cUnknown := parts[0], parts[1], parts[2], parts[3], parts[4]
	cState := []rune{cEmpty, cCheck, cUnknown}

	canvas.FillRect(x, y, w, h, term.Cell{Ch: ' ', Bg: bg})
	if w < 3 {
		return
	}

	canvas.PutSymbol(x, y, term.Cell{Ch: cOpen, Fg: fg, Bg: bg})
	canvas.PutSymbol(x+2, y, term.Cell{Ch: cClose, Fg: fg, Bg: bg})
	canvas.PutSymbol(x+1, y, term.Cell{Ch: cState[c.state], Fg: fg, Bg: bg})

	if w < 5 {
		return
	}

	shift, text := AlignText(c.title, w-4, c.align)
	canvas.PutText(x+4+shift, y, text, fg, bg)
}

func (c *CheckBox) ProcessEvent(event Event) bool {
	if (!c.Active() && event.Type == EventKey) || !c.Enabled() {
		return false
	}

	if (event.Type == EventKey && event.Key == term.KeySpace) || event.Type == EventMouse {
		if c.state == 0 {
			c.state = 1
		} else if c.state == 2 {
			c.state = 0
		} else {
			if c.allow3state {
				c.state = 2
			} else {
				c.state = 0
			}
		}
		return true
	}

	return false
}

// Sets the current state of CheckBox
// Value must be 0/1 if 3State is off
// or 0/1/2 if 3State is on
func (c *CheckBox) SetState(val int) {
	if val < 0 {
		val = 0
	}
	if val > 1 && !c.allow3state {
		val = 1
	}
	if val > 2 {
		val = 2
	}

	c.state = val
}

func (c *CheckBox) State() int {
	return c.state
}

// Set3State - sets if ComboBox should use 3 states. If the current
// state is unknown and one disables 3State option then the current
// value resets to off
func (c *CheckBox) SetAllow3State(enable bool) {
	if !enable && c.state == 2 {
		c.state = 0
	}
	c.allow3state = enable
}

// Allow3State - return true if ComboBox uses 3 states (on/off/unknown)
func (c *CheckBox) Allow3State() bool {
	return c.allow3state
}