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section-08.html
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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<link href="./main.css" rel="stylesheet">
</head>
<body>
<form>
<label for="input">Input</label>
<textarea id="input" rows="2"></textarea>
<div id="keyboards-list"><span>Keyboards:</span></div>
<div id="visual-scripts-list"></div>
<div id="keyboard" class="v2"></div>
<button id="submit" type="button">Submit</button>
<hr>
<label>Output</label>
<pre id="output"></pre>
</form>
</body>
<script>
/*
We're organising all the keyboard logic into a single 'KeyboardApp'.
*/
class KeyboardApp {
constructor () {
// Let's register all the HTML elements to make them easier to access later.
this.html = {
input: document.getElementById('input'),
keyboard: document.getElementById('keyboard'),
keyboardsList: document.getElementById('keyboards-list'),
visualScriptsList: document.getElementById('visual-scripts-list'),
submit: document.getElementById('submit'),
output: document.getElementById('output'),
}
// Let's register some event handling
this.html.input.onkeypress = this.onKeyPress.bind(this)
this.html.submit.onclick = this.submit.bind(this)
// Let's prepare the list of selectable keyboards
this.setupKeyboardsList()
// Let's set the default keyboard language
this.activeKeyboard = HEBREW_KEYBOARD
this.activeVisualScript = HEBREW_KEYBOARD.visualScripts['Yemenite Square']
this.setupVisualScriptsList()
this.setupKeyboard()
}
/*
This 'submit' logic is just placeholder for what you actually want to do.
Normally, this is where we'd submit the input data to a server. For our
example, we just print the text into the output field.
*/
submit () {
const text = input.value
output.innerText = text
}
/*
setupKeyboardsList() does exactly what it says on the tin.
*/
setupKeyboardsList () {
Object.entries(KEYBOARDS).forEach(([language, keyboard]) => {
const buttonKeyboard = document.createElement('button')
buttonKeyboard.type = 'button'
buttonKeyboard.innerText = language
buttonKeyboard.onclick = () => {
this.activeKeyboard = keyboard
this.activeVisualScript = undefined
this.setupVisualScriptsList()
this.setupKeyboard()
}
this.html.keyboardsList.appendChild(buttonKeyboard)
})
}
/*
If the selected keyboard (i.e. language) has a visual script reference (i.e.
handwritten image reference for each character), set it up here.
*/
setupVisualScriptsList () {
// First, we erase everything in the current list.
while (this.html.visualScriptsList.firstChild) {
this.html.visualScriptsList.removeChild(this.html.visualScriptsList.firstChild)
}
// If there's no active keyboard, or if the active keyboard doesn't have any
// visual script references, then we can call it quits!
if (!this.activeKeyboard || !this.activeKeyboard.visualScripts) {
this.html.visualScriptsList.style.display = 'none'
return
}
// OK, now let's create the buttons that will allow users to switch between
// the different visual references available.
this.html.visualScriptsList.style.display = 'block'
Object.entries(this.activeKeyboard.visualScripts).forEach(([scriptName, scriptData]) => {
const buttonVisualScript = document.createElement('button')
buttonVisualScript.type = 'button'
buttonVisualScript.innerText = scriptName
buttonVisualScript.onclick = () => {
this.activeVisualScript = scriptData
this.setupKeyboard()
}
this.html.visualScriptsList.appendChild(buttonVisualScript)
})
}
/*
setupKeyboard() does exactly what it says on the tin.
*/
setupKeyboard () {
// First, we erase everything in the current keyboard.
while (this.html.keyboard.firstChild) {
this.html.keyboard.removeChild(this.html.keyboard.firstChild)
}
// If there's no active keyboard, I guess we've got nothing to do!
if (!this.activeKeyboard) {
this.html.input.style.direction = 'ltr' // Default direction
return
}
// Right, now let's add the keys (buttons) for a QWERTY layout
QWERTY_LAYOUT.forEach((row) => {
const divRow = document.createElement('div')
divRow.className = 'row'
row.forEach((key) => {
// Create a button for each key in the QWERTY layout
const buttonKey = document.createElement('button')
buttonKey.className = 'keyboard-key'
buttonKey.type = 'button'
// Is there a character in our custom language keyboard that corresponds
// with this QWERTY key? If so, then pressing the key should insert
// the associated character.
const char = this.activeKeyboard.keys[key]
if (char) {
const hasVisualReference = this.activeVisualScript
&& this.activeKeyboard.visualScriptLayout
&& this.activeKeyboard.visualScriptLayout[char]
// If the character has a visual reference, we add a button with an image.
if (hasVisualReference) {
const characterPositionOnImage = this.activeKeyboard.visualScriptLayout[char]
const characterSizeOnImage = '50px' // We know this in advance
// We're using a CSS trick known as "image sprites".
// The visual reference image has ALL the characters in a given
// script, so we use CSS background image + positioning to only show
// specific parts of the whole reference image, corresponding to
// individual characters.
const visualSpan = document.createElement('div')
visualSpan.style.backgroundImage = 'url(' + this.activeVisualScript + ')'
visualSpan.style.backgroundPosition = -characterPositionOnImage.x + 'px ' + -characterPositionOnImage.y + 'px'
visualSpan.style.width = characterSizeOnImage
visualSpan.style.height = characterSizeOnImage
buttonKey.appendChild(visualSpan)
buttonKey.onclick = () => { this.insertChar(char) }
// Otherwise, we add a standard button.
} else {
buttonKey.innerText = char
buttonKey.onclick = () => { this.insertChar(char) }
}
} else {
buttonKey.innerText = ' '
}
// Add the 'shortcut' (i.e. the QWERTY key)
const shortcutSpan = document.createElement('span')
shortcutSpan.innerText = ENGLISH_KEYBOARD.keys[key]
buttonKey.appendChild(shortcutSpan)
divRow.appendChild(buttonKey)
})
this.html.keyboard.appendChild(divRow)
})
// Some keyboards/languages write from right to left. Update the CSS style
// for the text input field accordingly.
this.html.input.style.direction = this.activeKeyboard.direction || 'ltr'
}
/*
insertChar() inserts a single character to the (end of the) input text box.
*/
insertChar (char) {
// Find the position of the "text cursor" on the text input
const startIndex = this.html.input.selectionStart
const endIndex = this.html.input.selectionEnd
// Minor trivia: if the text cursor has selected some text (e.g. a user
// highlighted a word) then startIndex will not be the same as endIndex ;
// otherwise, startIndex will be the same as endIndex.
// Insert the new character where the text cursor is, OR replace the text
// that the text cursor is selecting.
const text = this.html.input.value
const startText = text.substring(0, startIndex)
const endText = text.substring(endIndex)
this.html.input.value = startText + char + endText
// Return focus to the input text box, and reset the "text cursor" to the
// location where we just inserted the character
this.html.input.focus()
const focusIndex = startIndex + char.length
this.html.input.setSelectionRange(focusIndex, focusIndex)
}
/*
onKeyPress listens for keyboard input on the text input field.
*/
onKeyPress (keyboardEvent) {
// Get the key that the user just pressed
const keyPressed = keyboardEvent.code
// Note: there are different ways to get what the user typed into a text
// field.
// keyboardEvent.code corresponds to the PHYSICAL key on the keyboard.
// keyboardEvent.key corresponds to the TEXT VALUE of the key.
// If a user presses the 'A' key on a US-International QWERTY keyboard,
// we get code='KeyA', and key='a' (if shift/capslock is off) or key='A'
// (if shift/capslock is on)
// Check to see if there's a character on the on-screen keyboard that
// corresponds to the key the user just pressed. If yes, insert that
// character.
const char = this.activeKeyboard && this.activeKeyboard.keys[keyPressed]
if (char) {
this.insertChar(char)
return stopEvent(keyboardEvent)
}
return true
}
}
/*
Stops the default actions for an input event. For example, pressing the 'A' key
on a keyboard will insert the character 'a' into a text input field. If we want
to change the action so the 'A' key inserts the 'あ' character, we first need to
disable the default action.
*/
function stopEvent (e) {
e.preventDefault && e.preventDefault()
e.stopPropagation && e.stopPropagation()
return false
}
/*
English Keyboard + QWERTY Layout: defines the baseline US-International QWERTY
keyboard that we assume each user is using.
*/
const ENGLISH_KEYBOARD = {
direction: 'ltr',
keys: {
'KeyQ': 'Q',
'KeyW': 'W',
'KeyE': 'E',
'KeyR': 'R',
'KeyT': 'T',
'KeyY': 'Y',
'KeyU': 'U',
'KeyI': 'I',
'KeyO': 'O',
'KeyP': 'P',
'BracketLeft': '[',
'BracketRight': ']',
// --------
'KeyA': 'A',
'KeyS': 'S',
'KeyD': 'D',
'KeyF': 'F',
'KeyG': 'G',
'KeyH': 'H',
'KeyJ': 'J',
'KeyK': 'K',
'KeyL': 'L',
'Semicolon': ';',
'Quote': '\'',
// --------
'KeyZ': 'Z',
'KeyX': 'X',
'KeyC': 'C',
'KeyV': 'V',
'KeyB': 'B',
'KeyN': 'N',
'KeyM': 'M',
'Comma': ',',
'Period': '.',
'Slash': '/',
}
}
const QWERTY_LAYOUT = [
[ 'KeyQ', 'KeyW', 'KeyE', 'KeyR', 'KeyT', 'KeyY', 'KeyU', 'KeyI', 'KeyO', 'KeyP', 'BracketLeft', 'BracketRight' ],
[ 'KeyA', 'KeyS', 'KeyD', 'KeyF', 'KeyG', 'KeyH', 'KeyJ', 'KeyK', 'KeyL', 'Semicolon', 'Quote' ],
[ 'KeyZ', 'KeyX', 'KeyC', 'KeyV', 'KeyB', 'KeyN', 'KeyM', 'Comma', 'Period', 'Slash' ]
]
/*
Hebrew Keyboard: translates key presses on a US-International QWERTY keyboard
into Hebrew characters.
*/
const HEBREW_KEYBOARD = {
direction: 'rtl',
keys: {
// 'KeyQ': 'Q',
// 'KeyW': 'W',
'KeyE': 'ק', // Qof
'KeyR': 'ר', // Resh
'KeyT': 'א', // Alef
'KeyY': 'ט', // Tet
'KeyU': 'ו', // Waw/Vav
'KeyI': 'ן', // Nun (2)
'KeyO': 'ם', // Mem (2)
'KeyP': 'פ', // Pe (1)
// 'BracketLeft': '[',
// 'BracketRight': ']',
// --------
'KeyA': 'ש', // Shin
'KeyS': 'ד', // Dalet
'KeyD': 'ג', // Gimel
'KeyF': 'כ', // Kaf
'KeyG': 'ע', // Ayin
'KeyH': 'י', // Yod
'KeyJ': 'ח', // Chet
'KeyK': 'ל', // Lamed
'KeyL': 'ך', // Kaf
'Semicolon': 'ף', // Pe (2)
// 'Quote': '\'',
// --------
'KeyZ': 'ז', // Zayin
'KeyX': 'ס', // Samech
'KeyC': 'ב', // Bet
'KeyV': 'ה', // He
'KeyB': 'נ', // Nun (1)
'KeyN': 'מ', // Mem (1)
'KeyM': 'צ', // Tsadik (1)
'Comma': 'ת', // Tav
'Period': 'ץ', // Tsadik (2)
'Slash': 'ﭏ', // Alef-lamed
},
// The following contains info on how to map each character (i.e. data) with a
// visual reference (i.e. image) of how the character looks like in a
// real-world manuscript written by human hands. (i.e. the Hebrew script)
visualScripts: {
'Yemenite Square': 'images/yemenite-square.jpg',
'none': undefined,
},
// To keep things simple, each image file (representing a Hebrew script and
// containing an instance of every handwritten character) follows a specific
// visual layout. For example, each handwritten Hebrew character's image is a
// 50x50px square located at specific x-y coordinates. This consistency allows
// us to use a CSS technique known as "image sprites" to package multiple
// character images into one file, which in turn lets us rapidly add new
// visual guides for different styles of Hebrew scripts.
visualScriptLayout: {
'ק': { x: 440, y: 256 }, // Qof
'ר': { x: 330, y: 256 }, // Resh
'א': { x: 440, y: 0 }, // Alef
'ט': { x: 110, y: 64 }, // Tet
'ו': { x: 275, y: 64 }, // Waw/Vav
'ן': { x: 385, y: 192 }, // Nun (2)
'ם': { x: 55, y: 128 }, // Mem (2)
'פ': { x: 165, y: 192 }, // Pe (1)
// --------
'ש': { x: 220, y: 256 }, // Shin
'ד': { x: 55, y: 0 }, // Dalet
'ג': { x: 110, y: 0 }, // Gimel
'כ': { x: 0, y: 64 }, // Kaf (1)
'ע': { x: 275, y: 192 }, // Ayin
'י': { x: 55, y: 64 }, // Yod
'ח': { x: 165, y: 64 }, // Chet
'ל': { x: 275, y: 128 }, // Lamed
'ך': { x: 440, y: 128 }, // Kaf (2)
'ף': { x: 110, y: 192 }, // Pe (2)
// --------
'ז': { x: 220, y: 64 }, // Zayin
'ס': { x: 55, y: 128 }, // Samech
'ב': { x: 220, y: 0 }, // Bet
'ה': { x: 440, y: 64 }, // He
'נ': { x: 440, y: 192 }, // Nun (1)
'מ': { x: 110, y: 256 }, // Mem (1)
'צ': { x: 55, y: 192 }, // Tsadik (1)
'ת': { x: 110, y: 256 }, // Tav
'ץ': { x: 0, y: 192 }, // Tsadik (2)
'ﭏ': { x: 330, y: 0 }, // Alef-lamed
},
}
/*
Emoji Keyboard: a joke keyboard to demonstrate how easy it is to add map keys
to characters of any 'language'.
*/
const EMOJI_KEYBOARD = {
direction: 'ltr',
keys: {
'KeyQ': '😃',
'KeyW': '😅',
'KeyE': '🤣',
'KeyR': '🥰',
'KeyT': '😉',
'KeyY': '😂',
'KeyU': '🥵',
'KeyI': '🥶',
'KeyO': '😍',
'KeyP': '😵',
'BracketLeft': '🎉',
'BracketRight': '🍎',
// --------
'KeyA': '🐈',
'KeyS': '🐕',
'KeyD': '🐒',
'KeyF': '🕊️',
'KeyG': '🐓',
'KeyH': '🐟',
'KeyJ': '🐙',
'KeyK': '🦑',
'KeyL': '🦋',
'Semicolon': '🔥',
'Quote': '💧',
// --------
'KeyZ': '❤️',
'KeyX': '🧡',
'KeyC': '💛',
'KeyV': '💚',
'KeyB': '💙',
'KeyN': '💜',
'KeyM': '🤎',
'Comma': '🖤',
'Period': '🤍',
'Slash': '💌',
}
}
const KEYBOARDS = {
'(No keyboard)': undefined,
'English': ENGLISH_KEYBOARD,
'Hebrew': HEBREW_KEYBOARD,
'Emoji': EMOJI_KEYBOARD,
}
var app = new KeyboardApp() // Let's start the app!
</script>
</html>