Respect the text input length restriction with IME composition.

mikke89 · Mar 16, 2024 · e022074 · e022074
1 parent 68f6f84
commit e022074
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Showing 4 changed files with 59 additions and 11 deletions.
diff --git a/Include/RmlUi/Core/TextInputMethodContext.h b/Include/RmlUi/Core/TextInputMethodContext.h
@@ -66,10 +66,13 @@ class RMLUICORE_API TextInputMethodContext {
 	/// @param[in] end The first character *after* the range.
 	virtual void SetText(StringView text, int start, int end) = 0;
 
-	/// Update the range of the text being composed (e.g., for visual feedback).
+	/// Update the range of the text being composed.
 	/// @param[in] start The first character in the range.
 	/// @param[in] end The first character *after* the range.
 	virtual void SetCompositionRange(int start, int end) = 0;
+
+	/// Commit the current composition.
+	virtual void CommitComposition() = 0;
 };
 
 } // namespace Rml

diff --git a/Samples/basic/ime/data/ime.rml b/Samples/basic/ime/data/ime.rml
@@ -25,7 +25,7 @@
 			input[type="text"], textarea {
 				width: 100%;
 				border: 1px gray;
-                margin-bottom: 10dp;
+				margin-bottom: 10dp;
 			}
 
 			.note {
@@ -36,10 +36,10 @@
 	<body>
 		<form>
 			<label for="text">Input text</label>
-			<input id="text" type="text" name="text" />
+			<input id="text" type="text" name="text" maxlength=100 />
 
-            <label for="text_area">Type long text</label>
-            <textarea rows=4 id="text_area" name="text_area"></textarea>
+			<label for="text_area">Type long text</label>
+			<textarea rows=4 id="text_area" name="text_area"></textarea>
 		</form>
 
 		<p class="note">Note: the emoji keyboard and clipboard history use IME, too.</p>

diff --git a/Source/Core/Elements/WidgetTextInput.cpp b/Source/Core/Elements/WidgetTextInput.cpp
@@ -84,15 +84,17 @@ class WidgetTextInputIMEContext final : public TextInputMethodContext {
 	WidgetTextInputIMEContext(WidgetTextInput* _owner);
 	~WidgetTextInputIMEContext() = default;
 
-	virtual void GetScreenBounds(Vector2f& position, Vector2f& size) const override;
-	virtual void GetSelectionRange(int& start, int& end) const override;
-	virtual void SetSelectionRange(int start, int end) override;
-	virtual void SetCursorPosition(int position) override;
-	virtual void SetText(StringView text, int start, int end) override;
-	virtual void SetCompositionRange(int start, int end) override;
+	void GetScreenBounds(Vector2f& position, Vector2f& size) const override;
+	void GetSelectionRange(int& start, int& end) const override;
+	void SetSelectionRange(int start, int end) override;
+	void SetCursorPosition(int position) override;
+	void SetText(StringView text, int start, int end) override;
+	void SetCompositionRange(int start, int end) override;
+	void CommitComposition() override;
 
 private:
 	WidgetTextInput* owner;
+	String composition;
 };
 
 WidgetTextInputIMEContext::WidgetTextInputIMEContext(WidgetTextInput* _owner) : owner(_owner) {}
@@ -129,13 +131,49 @@ void WidgetTextInputIMEContext::SetText(StringView text, int start, int end)
 	value.replace(start, end - start, text.begin(), text.size());
 
 	owner->parent->SetValue(value);
+
+	composition = String(text);
 }
 
 void WidgetTextInputIMEContext::SetCompositionRange(int start, int end)
 {
 	owner->SetIMERange(start, end);
 }
 
+void WidgetTextInputIMEContext::CommitComposition()
+{
+	const int start_byte = owner->ime_composition_begin_index;
+	const int end_byte = owner->ime_composition_end_index;
+
+	// No composition to commit.
+	if (start_byte == 0 && end_byte == 0)
+		return;
+
+	String value = owner->GetAttributeValue();
+
+	// If the text input has a length restriction, we have to shorten the composition string.
+	if (owner->GetMaxLength() >= 0)
+	{
+		int start = StringUtilities::ConvertByteOffsetToCharacterOffset(value, start_byte);
+		int end = StringUtilities::ConvertByteOffsetToCharacterOffset(value, end_byte);
+
+		int value_length = (int)StringUtilities::LengthUTF8(value);
+		int composition_length = (int)StringUtilities::LengthUTF8(composition);
+
+		// The requested text value would exceed the length restriction after replacing the original value.
+		if (value_length + composition_length - (start - end) > owner->GetMaxLength())
+		{
+			int new_length = owner->GetMaxLength() - (value_length - composition_length);
+			composition.erase(StringUtilities::ConvertCharacterOffsetToByteOffset(composition, new_length));
+		}
+	}
+
+	RMLUI_ASSERTMSG(end_byte >= start_byte, "Invalid end character offset.");
+	value.replace(start_byte, end_byte - start_byte, composition.data(), composition.size());
+
+	owner->parent->SetValue(value);
+}
+
 WidgetTextInput::WidgetTextInput(ElementFormControl* _parent) :
 	internal_dimensions(0, 0), scroll_offset(0, 0), cursor_position(0, 0), cursor_size(0, 0)
 {

diff --git a/Source/Core/TextInputMethodEditor.cpp b/Source/Core/TextInputMethodEditor.cpp
@@ -147,6 +147,13 @@ void DefaultTextInputMethodEditor::IMEConfirmComposition(StringView composition)
 	RMLUI_ASSERT(IsComposing());
 
 	SetCompositionString(composition);
+
+	RMLUI_ASSERT(!context.expired());
+	SharedPtr<TextInputMethodContext> _context = context.lock();
+
+	_context->SetCompositionRange(composition_range_start, composition_range_end);
+	_context->CommitComposition();
+
 	// Move the cursor to the end of the string.
 	SetCursorPosition(composition_range_end - composition_range_start, true);