On-screen keyboard widget for ebiten
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package kibodo
import (
"image"
"image/color"
"log"
"time"
"github.com/hajimehoshi/ebiten/v2"
"github.com/hajimehoshi/ebiten/v2/examples/resources/fonts"
"github.com/hajimehoshi/ebiten/v2/inpututil"
"github.com/hajimehoshi/ebiten/v2/text"
"golang.org/x/image/font"
"golang.org/x/image/font/opentype"
)
// Keyboard is an on-screen keyboard widget.
type Keyboard struct {
x, y int
w, h int
visible bool
alpha float64
passPhysical bool
allowUserHide bool
internalBuffer []rune
inputBuffer chan *Input
keys [][]*Key
background *ebiten.Image
backgroundDirty bool
op *ebiten.DrawImageOptions
backgroundColor color.Color
lastBackgroundColor color.Color
shift bool
touchIDs []ebiten.TouchID
hideShortcuts []ebiten.Key
labelFont font.Face
}
// NewKeyboard returns a new Keyboard.
func NewKeyboard() *Keyboard {
fontFace, err := defaultFontFace(64)
if err != nil {
log.Fatal(err)
}
k := &Keyboard{
alpha: 1.0,
op: &ebiten.DrawImageOptions{
Filter: ebiten.FilterNearest,
},
background: ebiten.NewImage(1, 1),
backgroundColor: color.Black,
labelFont: fontFace,
}
return k
}
func defaultFont() (*opentype.Font, error) {
return opentype.Parse(fonts.MPlus1pRegular_ttf)
}
func defaultFontFace(size float64) (font.Face, error) {
f, err := defaultFont()
if err != nil {
return nil, err
}
const dpi = 72 // TODO
return opentype.NewFace(f, &opentype.FaceOptions{
Size: size,
DPI: dpi,
Hinting: font.HintingFull,
})
}
// SetRect sets the position and size of the widget.
func (k *Keyboard) SetRect(x, y, w, h int) {
if k.x == x && k.y == y && k.w == w && k.h == h {
return
}
k.x, k.y, k.w, k.h = x, y, w, h
k.updateKeyRects()
k.backgroundDirty = true
}
func (k *Keyboard) GetKeys() [][]*Key {
return k.keys
}
func (k *Keyboard) SetKeys(keys [][]*Key) {
k.keys = keys
k.updateKeyRects()
k.backgroundDirty = true
}
func (k *Keyboard) SetLabelFont(face font.Face) {
k.labelFont = face
k.backgroundDirty = true
}
func (k *Keyboard) SetHideShortcuts(shortcuts []ebiten.Key) {
k.hideShortcuts = shortcuts
}
func (k *Keyboard) updateKeyRects() {
if len(k.keys) == 0 {
return
}
maxCells := 0
for _, rowKeys := range k.keys {
if len(rowKeys) > maxCells {
maxCells = len(rowKeys)
}
}
cellPaddingW := 7
cellPaddingH := 7
cellH := (k.h - (cellPaddingH * (len(k.keys) - 1))) / len(k.keys)
row := 0
for _, rowKeys := range k.keys {
if len(rowKeys) == 0 {
continue
}
cellW := (k.w - (cellPaddingW * (len(rowKeys) - 1))) / len(rowKeys)
for i, key := range rowKeys {
key.x = (cellW + cellPaddingW) * i
key.y = (cellH + cellPaddingH) * row
key.w = cellW
key.h = cellH
if i == len(rowKeys)-1 {
key.w = k.w - key.x
}
}
// Count non-empty rows only
row++
}
}
func (k *Keyboard) at(x, y int) *Key {
if !k.visible {
return nil
}
if x >= k.x && x <= k.x+k.w && y >= k.y && y <= k.y+k.h {
x, y = x-k.x, y-k.y // Offset
for _, rowKeys := range k.keys {
for _, key := range rowKeys {
if x >= key.x && x <= key.x+key.w && y >= key.y && y <= key.y+key.h {
return key
}
}
}
}
return nil
}
func (k *Keyboard) handleHideKey(inputKey ebiten.Key) bool {
if !k.allowUserHide {
return false
}
for _, key := range k.hideShortcuts {
if key == inputKey {
k.Hide()
return true
}
}
return false
}
func (k *Keyboard) Hit(key *Key) {
input := key.LowerInput
if k.shift {
input = key.UpperInput
}
if input.Key == ebiten.KeyShift {
k.shift = !k.shift
k.backgroundDirty = true
return
} else if k.handleHideKey(input.Key) {
// Hidden
return
}
k.inputBuffer <- input
}
// Update handles user input.
func (k *Keyboard) Update() error {
if !k.visible {
return nil
}
// Pass through physical keyboard input
if k.passPhysical {
// Read input characters
k.internalBuffer = ebiten.AppendInputChars(k.internalBuffer[:0])
if len(k.internalBuffer) > 0 {
for _, r := range k.internalBuffer {
k.inputBuffer <- &Input{Rune: r} // Pass through
}
} else {
// Read keys
for _, key := range allKeys {
if inpututil.IsKeyJustPressed(key) {
if k.handleHideKey(key) {
// Hidden
return nil
}
k.inputBuffer <- &Input{Key: key} // Pass through
}
}
}
}
// Handle mouse input
if inpututil.IsMouseButtonJustReleased(ebiten.MouseButtonLeft) {
x, y := ebiten.CursorPosition()
key := k.at(x, y)
if key != nil {
for _, rowKeys := range k.keys {
for _, rowKey := range rowKeys {
rowKey.pressed = false
}
}
key.pressed = true
k.backgroundDirty = true
k.Hit(key)
// TODO replace with pressUntil
go func() {
time.Sleep(50 * time.Millisecond)
key.pressed = false
k.backgroundDirty = true
ebiten.ScheduleFrame()
}()
}
} else if ebiten.IsMouseButtonPressed(ebiten.MouseButtonLeft) {
x, y := ebiten.CursorPosition()
key := k.at(x, y)
if key != nil {
key.pressed = true
k.backgroundDirty = true
}
}
// Handle touch input
k.touchIDs = inpututil.AppendJustPressedTouchIDs(k.touchIDs[:0])
for _, id := range k.touchIDs {
x, y := ebiten.TouchPosition(id)
key := k.at(x, y)
if key != nil {
key.pressed = true
k.backgroundDirty = true
k.Hit(key)
// TODO replace with pressUntil
go func() {
time.Sleep(50 * time.Millisecond)
key.pressed = false
k.backgroundDirty = true
ebiten.ScheduleFrame()
}()
}
}
return nil
}
func (k *Keyboard) offset(x, y int) (int, int) {
return x + k.x, y + k.y
}
func (k *Keyboard) drawBackground() {
if k.w == 0 || k.h == 0 {
return
}
if k.background == nil || k.background.Bounds() != image.Rect(0, 0, k.w, k.h) || k.backgroundColor != k.lastBackgroundColor {
k.background = ebiten.NewImageFromImage(image.NewRGBA(image.Rect(0, 0, k.w, k.h)))
k.background.Fill(k.backgroundColor)
k.lastBackgroundColor = k.backgroundColor
}
for _, rowKeys := range k.keys {
for _, key := range rowKeys {
label := key.LowerLabel
if k.shift {
label = key.UpperLabel
}
// Draw key background
img := ebiten.NewImageFromImage(image.NewRGBA(image.Rect(0, 0, key.w, key.h)))
img.Fill(color.RGBA{100, 100, 100, 255})
// Draw key label
bounds := text.BoundString(k.labelFont, label)
x := (key.w - bounds.Dx()) / 2
if x < 0 {
x = 0
}
y := key.h / 2
text.Draw(img, label, k.labelFont, x, y, color.White)
if key.pressed {
k.op.ColorM.Scale(0.75, 0.75, 0.75, 1)
}
// Draw key
k.op.GeoM.Reset()
k.op.GeoM.Translate(float64(key.x), float64(key.y))
k.background.DrawImage(img, k.op)
k.op.ColorM.Reset()
}
}
}
// Draw draws the widget on the provided image.
func (k *Keyboard) Draw(target *ebiten.Image) {
if !k.visible {
return
}
if k.backgroundDirty {
k.drawBackground()
k.backgroundDirty = false
}
k.op.GeoM.Reset()
k.op.GeoM.Translate(float64(k.x), float64(k.y))
k.op.ColorM.Scale(1, 1, 1, k.alpha)
target.DrawImage(k.background, k.op)
k.op.ColorM.Reset()
}
// SetAllowUserHide sets a flag that controls whether the widget may be hidden
// by the user. The input buffer channel is closed when the widget is hidden.
func (k *Keyboard) SetAllowUserHide(allow bool) {
k.allowUserHide = allow
}
// SetPassThroughPhysicalInput sets a flag that controls whether physical
// keyboard input is passed through to the widget's input buffer. This is not
// enabled by default.
func (k *Keyboard) SetPassThroughPhysicalInput(pass bool) {
k.passPhysical = pass
}
// SetAlpha sets the transparency level of the widget on a scale of 0 to 1.0.
func (k *Keyboard) SetAlpha(alpha float64) {
k.alpha = alpha
}
// Show shows the widget and begins sending input to the provided channel. The
// channel is closed if the widget is hidden.
func (k *Keyboard) Show(inputBuffer chan *Input) {
if k.inputBuffer != nil {
close(k.inputBuffer)
}
k.inputBuffer = inputBuffer
k.visible = true
}
func (k *Keyboard) Visible() bool {
return k.visible
}
// Hide hides the widget and closes the input buffer channel.
func (k *Keyboard) Hide() {
if k.inputBuffer != nil {
close(k.inputBuffer)
k.inputBuffer = nil
}
k.visible = false
}