[Complex Text Layouts] Refactor Font class, default themes and controls to use Text Server interface.

Implement interface mirroring.
Add TextLine and TextParagraph classes.
Handle UTF-16 input on macOS and Windows.

3 files changed, 88 insertions, 11 deletions

diff --git a/platform/android/display_server_android.cpp b/platform/android/display_server_android.cpp
index e82a12ece5..aab5da4fde 100644
--- a/platform/android/display_server_android.cpp
+++ b/platform/android/display_server_android.cpp
@@ -498,9 +498,28 @@ void DisplayServerAndroid::_set_key_modifier_state(Ref<InputEventWithModifiers>
 }
 
 void DisplayServerAndroid::process_key_event(int p_keycode, int p_scancode, int p_unicode_char, bool p_pressed) {
+	static char32_t prev_wc = 0;
+	char32_t unicode = p_unicode_char;
+	if ((p_unicode_char & 0xfffffc00) == 0xd800) {
+		if (prev_wc != 0) {
+			ERR_PRINT("invalid utf16 surrogate input");
+		}
+		prev_wc = unicode;
+		return; // Skip surrogate.
+	} else if ((unicode & 0xfffffc00) == 0xdc00) {
+		if (prev_wc == 0) {
+			ERR_PRINT("invalid utf16 surrogate input");
+			return; // Skip invalid surrogate.
+		}
+		unicode = (prev_wc << 10UL) + unicode - ((0xd800 << 10UL) + 0xdc00 - 0x10000);
+		prev_wc = 0;
+	} else {
+		prev_wc = 0;
+	}
+
 	Ref<InputEventKey> ev;
 	ev.instance();
-	int val = p_unicode_char;
+	int val = unicode;
 	int keycode = android_get_keysym(p_keycode);
 	int phy_keycode = android_get_keysym(p_scancode);
 
diff --git a/platform/osx/display_server_osx.mm b/platform/osx/display_server_osx.mm
index 1ad7117b39..3025210195 100644
--- a/platform/osx/display_server_osx.mm
+++ b/platform/osx/display_server_osx.mm
@@ -701,8 +701,6 @@ static const NSRange kEmptyRange = { NSNotFound, 0 };
 		characters = (NSString *)aString;
 	}
 
-	NSUInteger i, length = [characters length];
-
 	NSCharacterSet *ctrlChars = [NSCharacterSet controlCharacterSet];
 	NSCharacterSet *wsnlChars = [NSCharacterSet whitespaceAndNewlineCharacterSet];
 	if ([characters rangeOfCharacterFromSet:ctrlChars].length && [characters rangeOfCharacterFromSet:wsnlChars].length == 0) {
@@ -712,8 +710,15 @@ static const NSRange kEmptyRange = { NSNotFound, 0 };
 		return;
 	}
 
-	for (i = 0; i < length; i++) {
-		const unichar codepoint = [characters characterAtIndex:i];
+	Char16String text;
+	text.resize([characters length] + 1);
+	[characters getCharacters:(unichar *)text.ptrw() range:NSMakeRange(0, [characters length])];
+
+	String u32text;
+	u32text.parse_utf16(text.ptr(), text.length());
+
+	for (int i = 0; i < u32text.length(); i++) {
+		const char32_t codepoint = u32text[i];
 		if ((codepoint & 0xFF00) == 0xF700) {
 			continue;
 		}
@@ -1315,7 +1320,16 @@ static int remapKey(unsigned int key, unsigned int state) {
 
 		if (!wd.im_active && length > 0 && keycode_has_unicode(remapKey([event keyCode], [event modifierFlags]))) {
 			// Fallback unicode character handler used if IME is not active
-			for (NSUInteger i = 0; i < length; i++) {
+			Char16String text;
+			text.resize([characters length] + 1);
+			[characters getCharacters:(unichar *)text.ptrw() range:NSMakeRange(0, [characters length])];
+
+			String u32text;
+			u32text.parse_utf16(text.ptr(), text.length());
+
+			for (int i = 0; i < u32text.length(); i++) {
+				const char32_t codepoint = u32text[i];
+
 				DisplayServerOSX::KeyEvent ke;
 
 				ke.window_id = window_id;
@@ -1325,7 +1339,7 @@ static int remapKey(unsigned int key, unsigned int state) {
 				ke.keycode = remapKey([event keyCode], [event modifierFlags]);
 				ke.physical_keycode = translateKey([event keyCode]);
 				ke.raw = true;
-				ke.unicode = [characters characterAtIndex:i];
+				ke.unicode = codepoint;
 
 				_push_to_key_event_buffer(ke);
 			}
@@ -1417,7 +1431,15 @@ static int remapKey(unsigned int key, unsigned int state) {
 
 		// Fallback unicode character handler used if IME is not active
 		if (!wd.im_active && length > 0 && keycode_has_unicode(remapKey([event keyCode], [event modifierFlags]))) {
-			for (NSUInteger i = 0; i < length; i++) {
+			Char16String text;
+			text.resize([characters length] + 1);
+			[characters getCharacters:(unichar *)text.ptrw() range:NSMakeRange(0, [characters length])];
+
+			String u32text;
+			u32text.parse_utf16(text.ptr(), text.length());
+
+			for (int i = 0; i < u32text.length(); i++) {
+				const char32_t codepoint = u32text[i];
 				DisplayServerOSX::KeyEvent ke;
 
 				ke.window_id = window_id;
@@ -1427,7 +1449,7 @@ static int remapKey(unsigned int key, unsigned int state) {
 				ke.keycode = remapKey([event keyCode], [event modifierFlags]);
 				ke.physical_keycode = translateKey([event keyCode]);
 				ke.raw = true;
-				ke.unicode = [characters characterAtIndex:i];
+				ke.unicode = codepoint;
 
 				_push_to_key_event_buffer(ke);
 			}
diff --git a/platform/windows/display_server_windows.cpp b/platform/windows/display_server_windows.cpp
index dfbb734ee4..2581cc3af6 100644
--- a/platform/windows/display_server_windows.cpp
+++ b/platform/windows/display_server_windows.cpp
@@ -2792,6 +2792,24 @@ void DisplayServerWindows::_process_key_events() {
 			case WM_CHAR: {
 				// extended keys should only be processed as WM_KEYDOWN message.
 				if (!KeyMappingWindows::is_extended_key(ke.wParam) && ((i == 0 && ke.uMsg == WM_CHAR) || (i > 0 && key_event_buffer[i - 1].uMsg == WM_CHAR))) {
+					static char32_t prev_wc = 0;
+					char32_t unicode = ke.wParam;
+					if ((unicode & 0xfffffc00) == 0xd800) {
+						if (prev_wc != 0) {
+							ERR_PRINT("invalid utf16 surrogate input");
+						}
+						prev_wc = unicode;
+						break; // Skip surrogate.
+					} else if ((unicode & 0xfffffc00) == 0xdc00) {
+						if (prev_wc == 0) {
+							ERR_PRINT("invalid utf16 surrogate input");
+							break; // Skip invalid surrogate.
+						}
+						unicode = (prev_wc << 10UL) + unicode - ((0xd800 << 10UL) + 0xdc00 - 0x10000);
+						prev_wc = 0;
+					} else {
+						prev_wc = 0;
+					}
 					Ref<InputEventKey> k;
 					k.instance();
 
@@ -2803,7 +2821,7 @@ void DisplayServerWindows::_process_key_events() {
 					k->set_pressed(true);
 					k->set_keycode(KeyMappingWindows::get_keysym(ke.wParam));
 					k->set_physical_keycode(KeyMappingWindows::get_scansym((ke.lParam >> 16) & 0xFF, ke.lParam & (1 << 24)));
-					k->set_unicode(ke.wParam);
+					k->set_unicode(unicode);
 					if (k->get_unicode() && gr_mem) {
 						k->set_alt(false);
 						k->set_control(false);
@@ -2840,7 +2858,25 @@ void DisplayServerWindows::_process_key_events() {
 				k->set_physical_keycode(KeyMappingWindows::get_scansym((ke.lParam >> 16) & 0xFF, ke.lParam & (1 << 24)));
 
 				if (i + 1 < key_event_pos && key_event_buffer[i + 1].uMsg == WM_CHAR) {
-					k->set_unicode(key_event_buffer[i + 1].wParam);
+					char32_t unicode = key_event_buffer[i + 1].wParam;
+					static char32_t prev_wck = 0;
+					if ((unicode & 0xfffffc00) == 0xd800) {
+						if (prev_wck != 0) {
+							ERR_PRINT("invalid utf16 surrogate input");
+						}
+						prev_wck = unicode;
+						break; // Skip surrogate.
+					} else if ((unicode & 0xfffffc00) == 0xdc00) {
+						if (prev_wck == 0) {
+							ERR_PRINT("invalid utf16 surrogate input");
+							break; // Skip invalid surrogate.
+						}
+						unicode = (prev_wck << 10UL) + unicode - ((0xd800 << 10UL) + 0xdc00 - 0x10000);
+						prev_wck = 0;
+					} else {
+						prev_wck = 0;
+					}
+					k->set_unicode(unicode);
 				}
 				if (k->get_unicode() && gr_mem) {
 					k->set_alt(false);