According to spec: - The Enter, Tab and Backspace keys will not have release events unless "Report all keys as escape codes" is also set. - Key events that result in text are reported as plain UTF-8 text, so events are not supported for them, unless the application requests "key report" mode. I checked kitty's behavior. While it does report release events for keys that result in text as CSI sequences, press and repeat events for these are reported as plain UTF-8 text. This commit changes Xterm.js to match this behavior.
525 lines
15 KiB
TypeScript
525 lines
15 KiB
TypeScript
/**
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* Copyright (c) 2025 The xterm.js authors. All rights reserved.
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* @license MIT
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*
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* Kitty keyboard protocol implementation.
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* @see https://sw.kovidgoyal.net/kitty/keyboard-protocol/
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*/
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import { IKeyboardEvent, IKeyboardResult, KeyboardResultType } from 'common/Types';
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import { C0 } from 'common/data/EscapeSequences';
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/**
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* Kitty keyboard protocol enhancement flags (bitfield).
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*/
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export const enum KittyKeyboardFlags {
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NONE = 0b00000,
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/** Disambiguate escape codes - fixes ambiguous legacy encodings */
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DISAMBIGUATE_ESCAPE_CODES = 0b00001,
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/** Report event types - press/repeat/release */
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REPORT_EVENT_TYPES = 0b00010,
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/** Report alternate keys - shifted key and base layout key */
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REPORT_ALTERNATE_KEYS = 0b00100,
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/** Report all keys as escape codes - text-producing keys as CSI u */
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REPORT_ALL_KEYS_AS_ESCAPE_CODES = 0b01000,
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/** Report associated text - includes text codepoints in escape code */
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REPORT_ASSOCIATED_TEXT = 0b10000,
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}
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/**
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* Kitty keyboard event types.
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*/
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export const enum KittyKeyboardEventType {
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PRESS = 1,
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REPEAT = 2,
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RELEASE = 3,
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}
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/**
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* Kitty modifier bits (different from xterm modifier encoding).
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* Value sent = 1 + modifier_bits
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*/
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export const enum KittyKeyboardModifiers {
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SHIFT = 0b00000001,
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ALT = 0b00000010,
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CTRL = 0b00000100,
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SUPER = 0b00001000,
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HYPER = 0b00010000,
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META = 0b00100000,
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CAPS_LOCK = 0b01000000,
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NUM_LOCK = 0b10000000,
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}
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/**
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* Kitty keyboard protocol handler class.
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* Encapsulates all key code mappings and encoding logic.
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*/
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export class KittyKeyboard {
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/**
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* Functional key codes for Kitty protocol.
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* Keys that don't produce text have specific unicode codepoint mappings.
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*/
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private readonly _functionalKeyCodes: { [key: string]: number } = {
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'Escape': 27,
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'Enter': 13,
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'Tab': 9,
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'Backspace': 127,
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'CapsLock': 57358,
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'ScrollLock': 57359,
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'NumLock': 57360,
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'PrintScreen': 57361,
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'Pause': 57362,
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'ContextMenu': 57363,
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// F13-F35 (F1-F12 use legacy encoding)
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'F13': 57376,
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'F14': 57377,
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'F15': 57378,
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'F16': 57379,
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'F17': 57380,
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'F18': 57381,
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'F19': 57382,
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'F20': 57383,
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'F21': 57384,
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'F22': 57385,
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'F23': 57386,
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'F24': 57387,
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'F25': 57388,
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// Keypad keys
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'KP_0': 57399,
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'KP_1': 57400,
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'KP_2': 57401,
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'KP_3': 57402,
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'KP_4': 57403,
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'KP_5': 57404,
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'KP_6': 57405,
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'KP_7': 57406,
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'KP_8': 57407,
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'KP_9': 57408,
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'KP_Decimal': 57409,
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'KP_Divide': 57410,
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'KP_Multiply': 57411,
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'KP_Subtract': 57412,
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'KP_Add': 57413,
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'KP_Enter': 57414,
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'KP_Equal': 57415,
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// Modifier keys
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'ShiftLeft': 57441,
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'ShiftRight': 57447,
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'ControlLeft': 57442,
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'ControlRight': 57448,
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'AltLeft': 57443,
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'AltRight': 57449,
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'MetaLeft': 57444,
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'MetaRight': 57450,
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// Media keys
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'MediaPlayPause': 57430,
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'MediaStop': 57432,
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'MediaTrackNext': 57435,
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'MediaTrackPrevious': 57436,
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'AudioVolumeDown': 57438,
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'AudioVolumeUp': 57439,
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'AudioVolumeMute': 57440
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};
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/**
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* Keys that use CSI ~ encoding with a number parameter.
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*/
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private readonly _csiTildeKeys: { [key: string]: number } = {
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'Insert': 2,
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'Delete': 3,
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'PageUp': 5,
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'PageDown': 6,
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'F5': 15,
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'F6': 17,
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'F7': 18,
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'F8': 19,
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'F9': 20,
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'F10': 21,
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'F11': 23,
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'F12': 24
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};
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/**
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* Keys that use CSI letter encoding (arrows, Home, End).
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*/
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private readonly _csiLetterKeys: { [key: string]: string } = {
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'ArrowUp': 'A',
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'ArrowDown': 'B',
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'ArrowRight': 'C',
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'ArrowLeft': 'D',
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'Home': 'H',
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'End': 'F'
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};
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/**
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* Function keys F1-F4 use SS3 encoding without modifiers.
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*/
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private readonly _ss3FunctionKeys: { [key: string]: string } = {
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'F1': 'P',
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'F2': 'Q',
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'F3': 'R',
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'F4': 'S'
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};
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/**
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* Map browser key codes to Kitty numpad codes.
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*/
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private _getNumpadKeyCode(ev: IKeyboardEvent): number | undefined {
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if (ev.code.startsWith('Numpad')) {
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const suffix = ev.code.slice(6);
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if (suffix >= '0' && suffix <= '9') {
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return 57399 + parseInt(suffix, 10);
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}
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switch (suffix) {
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case 'Decimal': return 57409;
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case 'Divide': return 57410;
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case 'Multiply': return 57411;
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case 'Subtract': return 57412;
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case 'Add': return 57413;
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case 'Enter': return 57414;
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case 'Equal': return 57415;
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}
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}
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return undefined;
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}
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/**
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* Get modifier key code from code property.
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*/
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private _getModifierKeyCode(ev: IKeyboardEvent): number | undefined {
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switch (ev.code) {
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case 'ShiftLeft': return 57441;
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case 'ShiftRight': return 57447;
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case 'ControlLeft': return 57442;
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case 'ControlRight': return 57448;
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case 'AltLeft': return 57443;
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case 'AltRight': return 57449;
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case 'MetaLeft': return 57444;
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case 'MetaRight': return 57450;
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}
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return undefined;
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}
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/**
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* Encode modifiers for Kitty protocol.
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* Returns 1 + modifier bits, or 0 if no modifiers.
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*/
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private _encodeModifiers(ev: IKeyboardEvent): number {
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let mods = 0;
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if (ev.shiftKey) mods |= KittyKeyboardModifiers.SHIFT;
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if (ev.altKey) mods |= KittyKeyboardModifiers.ALT;
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if (ev.ctrlKey) mods |= KittyKeyboardModifiers.CTRL;
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if (ev.metaKey) mods |= KittyKeyboardModifiers.SUPER;
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return mods > 0 ? mods + 1 : 0;
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}
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/**
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* Get the unicode key code for a keyboard event.
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* Returns the lowercase codepoint for letters.
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* For shifted keys, uses the code property to get the base key.
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*/
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private _getKeyCode(ev: IKeyboardEvent, macOptionAsAlt: boolean): number | undefined {
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const numpadCode = this._getNumpadKeyCode(ev);
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if (numpadCode !== undefined) {
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return numpadCode;
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}
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const modifierCode = this._getModifierKeyCode(ev);
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if (modifierCode !== undefined) {
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return modifierCode;
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}
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const funcCode = this._functionalKeyCodes[ev.key];
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if (funcCode !== undefined) {
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return funcCode;
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}
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if ((ev.shiftKey || (macOptionAsAlt && ev.altKey)) && ev.code) {
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if (ev.code.startsWith('Digit') && ev.code.length === 6) {
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const digit = ev.code.charAt(5);
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if (digit >= '0' && digit <= '9') {
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return digit.charCodeAt(0);
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}
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}
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if (ev.code.startsWith('Key') && ev.code.length === 4) {
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const letter = ev.code.charAt(3).toLowerCase();
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return letter.charCodeAt(0);
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}
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}
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if (ev.key.length === 1) {
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const code = ev.key.codePointAt(0)!;
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if (code >= 65 && code <= 90) {
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return code + 32;
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}
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return code;
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}
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return undefined;
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}
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/**
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* Check if a key is a modifier key.
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*/
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private _isModifierKey(ev: IKeyboardEvent): boolean {
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return ev.key === 'Shift' || ev.key === 'Control' || ev.key === 'Alt' || ev.key === 'Meta';
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}
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/**
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* Check if a key is a lock key (CapsLock/NumLock/ScrollLock).
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*
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* Kitty's reference implementation classifies these as modifier keys for the
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* purpose of suppressing press events (kitty/keys.c `is_modifier_key()`
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* includes `GLFW_FKEY_CAPS_LOCK`, `GLFW_FKEY_SCROLL_LOCK`, `GLFW_FKEY_NUM_LOCK`),
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* and its test suite asserts that a CapsLock press with no protocol flags
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* produces empty output.
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*/
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private _isLockKey(ev: IKeyboardEvent): boolean {
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return ev.key === 'CapsLock' || ev.key === 'NumLock' || ev.key === 'ScrollLock';
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}
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/**
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* Build CSI letter sequence for arrow keys, Home, End.
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* Format: CSI [1;mod] letter
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*/
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private _buildCsiLetterSequence(
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letter: string,
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modifiers: number,
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eventType: KittyKeyboardEventType,
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reportEventTypes: boolean
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): string {
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const needsEventType = reportEventTypes && eventType !== KittyKeyboardEventType.PRESS;
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if (modifiers > 0 || needsEventType) {
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let seq = C0.ESC + '[1;' + (modifiers > 0 ? modifiers : '1');
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if (needsEventType) {
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seq += ':' + eventType;
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}
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seq += letter;
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return seq;
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}
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return C0.ESC + '[' + letter;
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}
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/**
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* Build SS3 sequence for F1-F4.
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* Without modifiers: SS3 letter
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* With modifiers: CSI 1;mod letter
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*/
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private _buildSs3Sequence(
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letter: string,
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modifiers: number,
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eventType: KittyKeyboardEventType,
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reportEventTypes: boolean
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): string {
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const needsEventType = reportEventTypes && eventType !== KittyKeyboardEventType.PRESS;
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if (modifiers > 0 || needsEventType) {
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let seq = C0.ESC + '[1;' + (modifiers > 0 ? modifiers : '1');
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if (needsEventType) {
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seq += ':' + eventType;
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}
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seq += letter;
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return seq;
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}
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return C0.ESC + 'O' + letter;
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}
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/**
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* Build CSI ~ sequence for Insert, Delete, PageUp/Down, F5-F12.
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* Format: CSI number [;mod[:event]] ~
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*/
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private _buildCsiTildeSequence(
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number: number,
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modifiers: number,
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eventType: KittyKeyboardEventType,
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reportEventTypes: boolean
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): string {
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const needsEventType = reportEventTypes && eventType !== KittyKeyboardEventType.PRESS;
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let seq = C0.ESC + '[' + number;
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if (modifiers > 0 || needsEventType) {
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seq += ';' + (modifiers > 0 ? modifiers : '1');
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if (needsEventType) {
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seq += ':' + eventType;
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}
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}
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seq += '~';
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return seq;
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}
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/**
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* Build CSI u sequence.
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* Format: CSI keycode[:shifted[:base]] [;mod[:event][;text]] u
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*/
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private _buildCsiUSequence(
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ev: IKeyboardEvent,
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keyCode: number,
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modifiers: number,
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eventType: KittyKeyboardEventType,
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flags: number,
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isFunc: boolean,
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isMod: boolean
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): string {
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const reportEventTypes = !!(flags & KittyKeyboardFlags.REPORT_EVENT_TYPES);
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const reportAlternateKeys = !!(flags & KittyKeyboardFlags.REPORT_ALTERNATE_KEYS);
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let seq = C0.ESC + '[' + keyCode;
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let shiftedKey: number | undefined;
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if (reportAlternateKeys && ev.shiftKey && ev.key.length === 1 && !isFunc && !isMod) {
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shiftedKey = ev.key.codePointAt(0);
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seq += ':' + shiftedKey;
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}
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const reportAssociatedText = !!(flags & KittyKeyboardFlags.REPORT_ASSOCIATED_TEXT) &&
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eventType !== KittyKeyboardEventType.RELEASE &&
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ev.key.length === 1 &&
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!isFunc &&
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!isMod &&
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!ev.ctrlKey;
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const textCode = reportAssociatedText ? ev.key.codePointAt(0) : undefined;
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const needsEventType = reportEventTypes &&
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eventType !== KittyKeyboardEventType.PRESS &&
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(eventType === KittyKeyboardEventType.RELEASE || textCode === undefined);
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if (modifiers > 0 || needsEventType || textCode !== undefined) {
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seq += ';';
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if (modifiers > 0) {
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seq += modifiers;
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} else if (needsEventType) {
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seq += '1';
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}
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if (needsEventType) {
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seq += ':' + eventType;
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}
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}
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if (textCode !== undefined) {
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seq += ';' + textCode;
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}
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seq += 'u';
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return seq;
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}
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/**
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* Evaluate a keyboard event using Kitty keyboard protocol.
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*
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* @param ev The keyboard event.
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* @param flags The active Kitty keyboard enhancement flags.
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* @param eventType The event type (press, repeat, release).
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* @param macOptionAsAlt When true, macOS Option-composed ev.key values are unwound via ev.code.
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* @returns The keyboard result with the encoded key sequence.
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*/
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public evaluate(
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ev: IKeyboardEvent,
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flags: number,
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eventType: KittyKeyboardEventType = KittyKeyboardEventType.PRESS,
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macOptionAsAlt: boolean = false
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): IKeyboardResult {
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const result: IKeyboardResult = {
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type: KeyboardResultType.SEND_KEY,
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cancel: false,
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key: undefined
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};
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const modifiers = this._encodeModifiers(ev);
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const isMod = this._isModifierKey(ev);
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const reportEventTypes = !!(flags & KittyKeyboardFlags.REPORT_EVENT_TYPES);
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if (!reportEventTypes && eventType === KittyKeyboardEventType.RELEASE) {
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return result;
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}
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if (isMod && !(flags & KittyKeyboardFlags.REPORT_ALL_KEYS_AS_ESCAPE_CODES)) {
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return result;
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}
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// Spec § "Report all keys as escape codes": "Additionally, with this mode,
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// events for pressing modifier keys are reported." — i.e. *without* this
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// mode, modifier-key press events are suppressed. Kitty's is_modifier_key()
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// treats CapsLock/NumLock/ScrollLock as modifier keys for this rule.
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if (this._isLockKey(ev) && !(flags & KittyKeyboardFlags.REPORT_ALL_KEYS_AS_ESCAPE_CODES)) {
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return result;
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}
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const csiLetter = this._csiLetterKeys[ev.key];
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if (csiLetter) {
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result.key = this._buildCsiLetterSequence(csiLetter, modifiers, eventType, reportEventTypes);
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result.cancel = true;
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return result;
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}
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const ss3Letter = this._ss3FunctionKeys[ev.key];
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if (ss3Letter) {
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result.key = this._buildSs3Sequence(ss3Letter, modifiers, eventType, reportEventTypes);
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result.cancel = true;
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return result;
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}
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const tildeCode = this._csiTildeKeys[ev.key];
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if (tildeCode !== undefined) {
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result.key = this._buildCsiTildeSequence(tildeCode, modifiers, eventType, reportEventTypes);
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result.cancel = true;
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return result;
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}
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const keyCode = this._getKeyCode(ev, macOptionAsAlt);
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if (keyCode === undefined) {
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return result;
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}
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const isFunc = this._functionalKeyCodes[ev.key] !== undefined || this._getNumpadKeyCode(ev) !== undefined;
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let useCsiU = false;
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if (flags & KittyKeyboardFlags.REPORT_ALL_KEYS_AS_ESCAPE_CODES) {
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useCsiU = true;
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} else if (reportEventTypes && eventType === KittyKeyboardEventType.RELEASE) {
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// Per spec, Enter/Tab/Backspace will not have release events unless "Report all keys as
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// escape codes" (which is handled by the branch above) is also set.
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if (keyCode === 13 || keyCode === 9 || keyCode === 127) {
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return result;
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}
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useCsiU = true;
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} else if (flags & KittyKeyboardFlags.DISAMBIGUATE_ESCAPE_CODES) {
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// Per spec, Enter/Tab/Backspace "still generate the same bytes as in legacy
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// mode" and consider space to be a text-generating key, so these skip the isFunc fast-path
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// and only get CSI u when modifiers are present (handled below).
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const isDisambiguateLegacy = keyCode === 13 || keyCode === 9 || keyCode === 127;
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if (isFunc && !isDisambiguateLegacy) {
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useCsiU = true;
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} else if (modifiers > 0) {
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if (ev.shiftKey && !ev.ctrlKey && !ev.altKey && !ev.metaKey && ev.key.length === 1) {
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useCsiU = false;
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} else {
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useCsiU = true;
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}
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}
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}
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if (useCsiU) {
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result.key = this._buildCsiUSequence(ev, keyCode, modifiers, eventType, flags, isFunc, isMod);
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result.cancel = true;
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} else {
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const legacyByte = keyCode === 13 ? '\r' : keyCode === 9 ? '\t' : keyCode === 127 ? '\x7f' : undefined;
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if (legacyByte) {
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result.key = legacyByte;
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} else if (ev.key.length === 1 && !ev.ctrlKey && !ev.altKey && !ev.metaKey) {
|
|
result.key = ev.key;
|
|
}
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
/**
|
|
* Check if Kitty protocol should be used based on flags.
|
|
*/
|
|
public static shouldUseProtocol(flags: number): boolean {
|
|
return flags > 0;
|
|
}
|
|
}
|