Windows-compatible kitty keyboard protocol implementation; Public Domain

gistfile1.txt

if (_kitty_kb_flags) {

	// References:
	// https://sw.kovidgoyal.net/kitty/keyboard-protocol/
	// https://learn.microsoft.com/en-us/windows/win32/inputdev/virtual-key-codes

	char buffer[64] = {0};

	const bool ctrl = (KeyEvent.dwControlKeyState & (LEFT_CTRL_PRESSED|RIGHT_CTRL_PRESSED)) != 0;
	const bool alt = (KeyEvent.dwControlKeyState & (RIGHT_ALT_PRESSED|LEFT_ALT_PRESSED)) != 0;
	const bool shift = (KeyEvent.dwControlKeyState & (SHIFT_PRESSED)) != 0;

	int keycode = towlower(KeyEvent.uChar.UnicodeChar);

	int base = 0;
	if ((KeyEvent.wVirtualKeyCode >= 'A') && (KeyEvent.wVirtualKeyCode <= 'Z')) {
		base = towlower(KeyEvent.wVirtualKeyCode);
		if (base == keycode) { base = 0; }
	}

	if (base && !keycode) { keycode = base; }

	int shifted = 0;

	if (shift || (KeyEvent.uChar.UnicodeChar && iswupper(KeyEvent.uChar.UnicodeChar))) {
		shifted = KeyEvent.uChar.UnicodeChar;
	}

	int modifiers = 0;

	if (shift) modifiers |= 1;
	if (alt)   modifiers |= 2;
	if (ctrl)  modifiers |= 4;
	if (KeyEvent.dwControlKeyState & CAPSLOCK_ON) modifiers |= 64;
	if (KeyEvent.dwControlKeyState & NUMLOCK_ON)  modifiers |= 128;

	modifiers += 1; // as spec requres

	char suffix = 'u';

	// apply modifications for special keys

	switch (KeyEvent.wVirtualKeyCode) {
		case VK_ESCAPE:    keycode = 27;  break;
		case VK_RETURN:    keycode = 13;  break;

		case VK_TAB:       keycode = 9;   break;
		case VK_BACK:      keycode = 127; break;

		case VK_INSERT:    keycode = 2;   suffix = '~'; break;
		case VK_DELETE:    keycode = 3;   suffix = '~'; break;

		case VK_LEFT:      keycode = 1;   suffix = 'D'; break;
		case VK_RIGHT:     keycode = 1;   suffix = 'C'; break;
		case VK_UP:        keycode = 1;   suffix = 'A'; break;
		case VK_DOWN:      keycode = 1;   suffix = 'B'; break;

		case VK_PRIOR:     keycode = 5;   suffix = '~'; break;
		case VK_NEXT:      keycode = 6;   suffix = '~'; break;

		case VK_HOME:      keycode = 1;   suffix = 'H'; break;
		case VK_END:       keycode = 1;   suffix = 'F'; break;

		case VK_F1:        keycode = 11;  suffix = '~'; break;
		case VK_F2:        keycode = 12;  suffix = '~'; break;
		case VK_F3:        keycode = 13;  suffix = '~'; break;
		case VK_F4:        keycode = 14;  suffix = '~'; break;
		case VK_F5:        keycode = 15;  suffix = '~'; break;

		case VK_F6:        keycode = 17;  suffix = '~'; break;
		case VK_F7:        keycode = 18;  suffix = '~'; break;
		case VK_F8:        keycode = 19;  suffix = '~'; break;
		case VK_F9:        keycode = 20;  suffix = '~'; break;
		case VK_F10:       keycode = 21;  suffix = '~'; break;

		case VK_F11:       keycode = 23;  suffix = '~'; break;
		case VK_F12:       keycode = 24;  suffix = '~'; break;

		case VK_MENU:
		{
			if (KeyEvent.dwControlKeyState & ENHANCED_KEY) {
				// right
				keycode = 57449; suffix = 'u';
			} else {
				// left
				keycode = 57443; suffix = 'u';
			}

			break;
		}

		case VK_CONTROL:
		{
			if ((KeyEvent.dwControlKeyState & ENHANCED_KEY)) {
				// right
				keycode = 57448; suffix = 'u';
			} else {
				// left
				keycode = 57442; suffix = 'u';
			}

			break;
		}

		case VK_SHIFT:
		{
			if (KeyEvent.wVirtualScanCode == RIGHT_SHIFT_VSC) {
				// right
				keycode = 57447; suffix = 'u';
			} else {
				// left
				keycode = 57441; suffix = 'u';
			}

			break;
		}
	}

	// avoid sending base char if it is equal to keycode
	if (base == keycode) { base = 0; }

	int flags = _kitty_kb_flags;


	if (!(flags & 8)) { // "Report all keys as escape codes" disabled
		// do not sent modifiers themselfs
		if (!keycode && (modifiers > 1)) {
			return "";
		}
	}

	// Generate ESC sequence, format:
	// CSI unicode-key-code:shifted-key:base-layout-key ; modifiers:event-type ; text-as-codepoints u

	int len = 0;

	len += snprintf(buffer + len, sizeof(buffer) - len, "\x1B[");

	// Part 1

	// We are not able to generate proper sequence for this key for now, sorry
	if (!keycode) { return ""; }

	len += snprintf(buffer + len, sizeof(buffer) - len, "%i", keycode);

	if ((flags & 4) && (shifted || base)) { // "report alternative keys" enabled

		len += snprintf(buffer + len, sizeof(buffer) - len, ":");

		if (shifted) {
			len += snprintf(buffer + len, sizeof(buffer) - len, "%i", shifted);
		}

		if (base) {

			len += snprintf(buffer + len, sizeof(buffer) - len, ":%i", base);
		}
	}

	// Part 2

	if ((modifiers > 1) || ((flags & 2) && !KeyEvent.bKeyDown)) {

		len += snprintf(buffer + len, sizeof(buffer) - len, ";");

		len += snprintf(buffer + len, sizeof(buffer) - len, "%i", modifiers);

		if ((flags & 2) && !KeyEvent.bKeyDown) {
			len += snprintf(buffer + len, sizeof(buffer) - len, ":%i", 3);
		}
	}

	// Part 3

	if ((flags & 16) && KeyEvent.uChar.UnicodeChar) {

		if (!((modifiers > 1) || ((flags & 2) && !KeyEvent.bKeyDown))) {
			// If no part 2, lets add ";"
			len += snprintf(buffer + len, sizeof(buffer) - len, ";");
		}

		len += snprintf(buffer + len, sizeof(buffer) - len, ";%i", KeyEvent.uChar.UnicodeChar);
	}

	// Finally

	len += snprintf(buffer + len, sizeof(buffer) - len, "%c", suffix);

	if (!(flags & 8) && KeyEvent.uChar.UnicodeChar && !alt && !ctrl) {
        // "Report all keys as escape codes" disabled
		// just send text
		len = snprintf(buffer, sizeof(buffer), "%lc", KeyEvent.uChar.UnicodeChar);
	}

	return buffer;
}