objects/numberinput.go

package objects

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

// NumberInput is an editable text box which accepts only numbers, and has
// controls to increment and decrement its value.
type NumberInput struct {
	tomo.ContainerBox
	input     *TextInput
	increment *Button
	decrement *Button
	on struct {
		enter       event.FuncBroadcaster
		valueChange event.FuncBroadcaster
	}
}

// NewNumberInput creates a new number input with the specified value.
func NewNumberInput (value float64) *NumberInput {
	box := &NumberInput {
		ContainerBox: tomo.NewContainerBox(),
		input:        NewTextInput(""),
		increment:    NewButton(""),
		decrement:    NewButton(""),
	}
	box.SetRole(tomo.R("objects", "NumberInput", ""))
	box.Add(box.input)
	box.Add(box.decrement)
	box.Add(box.increment)
	box.SetLayout(layouts.Row { true, false, false })
	box.increment.SetIcon(tomo.IconValueIncrement)
	box.decrement.SetIcon(tomo.IconValueDecrement)
	
	box.SetValue(value)
	
	box.CaptureScroll(true)
	box.CaptureKeyboard(true)
	
	box.OnScroll(box.handleScroll)
	box.OnKeyDown(box.handleKeyDown)
	box.input.OnEnter(box.handleEnter)
	box.input.OnValueChange(box.on.valueChange.Broadcast)
	box.increment.OnClick(func () { box.shift(1)  })
	box.decrement.OnClick(func () { box.shift(-1) })
	return box
}

// Value returns the value of the input.
func (this *NumberInput) Value () float64 {
	value, _ := strconv.ParseFloat(this.input.Text(), 64)
	return value
}

// SetValue sets the value of the input.
func (this *NumberInput) SetValue (value float64) {
	this.input.SetText(strconv.FormatFloat(value, 'g', -1, 64))
}

// OnValueChange specifies a function to be called when the user edits the input
// value.
func (this *NumberInput) OnValueChange (callback func ()) event.Cookie {
	return this.on.valueChange.Connect(callback)
}

// OnEnter specifies a function to be called when the user presses enter within
// the text input.
func (this *NumberInput) OnEnter (callback func ()) event.Cookie {
	return this.on.enter.Connect(callback)
}

func (this *NumberInput) shift (by int) {
	this.SetValue(this.Value() + float64(by))
	this.on.valueChange.Broadcast()
}

func (this *NumberInput) handleKeyDown (key input.Key, numpad bool) {
	switch key {
	case input.KeyUp:   this.shift(1)
	case input.KeyDown: this.shift(-1)
	default:            this.input.handleKeyDown(key, numpad)
	}
}

func (this *NumberInput) handleScroll (x, y float64) {
	if x == 0 {
		this.shift(-int(math.Round(y)))
	} else {
		this.input.handleScroll(x, y)
	}
}

func (this *NumberInput) handleEnter () {
	this.SetValue(this.Value())
	this.on.enter.Broadcast()
}