From 4edd8e8c5e4c6da7f4e5525050a8cdd01e2b0035 Mon Sep 17 00:00:00 2001
From: Timothy Flynn <trflynn89@pm.me>
Date: Mon, 27 Feb 2023 08:16:48 -0500
Subject: [PATCH] LibGUI: Ensure the "End" key sets the cursor to the visual
 line end

We are currently setting the physical mouse position to the visual
cursor content location. In a line containing only a multi-code point
emoji, this would set the cursor to column 1 rather than however many
code points there are.
---
 Userland/Libraries/LibGUI/EditingEngine.cpp |  8 +++-----
 Userland/Libraries/LibGUI/TextEditor.cpp    | 13 +++++++++++++
 Userland/Libraries/LibGUI/TextEditor.h      |  1 +
 3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/Userland/Libraries/LibGUI/EditingEngine.cpp b/Userland/Libraries/LibGUI/EditingEngine.cpp
index 0ff7952a03d..984690e3ab1 100644
--- a/Userland/Libraries/LibGUI/EditingEngine.cpp
+++ b/Userland/Libraries/LibGUI/EditingEngine.cpp
@@ -271,12 +271,10 @@ void EditingEngine::move_to_line_beginning()
 
 void EditingEngine::move_to_line_end()
 {
-    if (m_editor->is_wrapping_enabled()) {
-        auto end_position = m_editor->cursor_content_rect().location().translated(m_editor->width(), 0);
-        m_editor->set_cursor(m_editor->text_position_at_content_position(end_position));
-    } else {
+    if (m_editor->is_wrapping_enabled())
+        m_editor->set_cursor_to_end_of_visual_line();
+    else
         move_to_logical_line_end();
-    }
 }
 
 void EditingEngine::move_to_logical_line_end()
diff --git a/Userland/Libraries/LibGUI/TextEditor.cpp b/Userland/Libraries/LibGUI/TextEditor.cpp
index 9428a62191b..e3619f01c6e 100644
--- a/Userland/Libraries/LibGUI/TextEditor.cpp
+++ b/Userland/Libraries/LibGUI/TextEditor.cpp
@@ -1418,6 +1418,19 @@ void TextEditor::set_cursor_to_text_position(Gfx::IntPoint position)
     set_cursor({ visual_position.line(), physical_column });
 }
 
+void TextEditor::set_cursor_to_end_of_visual_line()
+{
+    for_each_visual_line(m_cursor.line(), [&](auto const&, auto& view, size_t start_of_visual_line, auto) {
+        if (m_cursor.column() < start_of_visual_line)
+            return IterationDecision::Continue;
+        if ((m_cursor.column() - start_of_visual_line) >= view.length())
+            return IterationDecision::Continue;
+
+        set_cursor(m_cursor.line(), start_of_visual_line + view.length());
+        return IterationDecision::Break;
+    });
+}
+
 void TextEditor::focusin_event(FocusEvent& event)
 {
     if (event.source() == FocusSource::Keyboard)
diff --git a/Userland/Libraries/LibGUI/TextEditor.h b/Userland/Libraries/LibGUI/TextEditor.h
index 4892794f291..1146a0c1f78 100644
--- a/Userland/Libraries/LibGUI/TextEditor.h
+++ b/Userland/Libraries/LibGUI/TextEditor.h
@@ -191,6 +191,7 @@ public:
     void set_cursor(size_t line, size_t column);
     virtual void set_cursor(TextPosition const&);
     void set_cursor_to_text_position(Gfx::IntPoint);
+    void set_cursor_to_end_of_visual_line();
 
     Syntax::Highlighter* syntax_highlighter();
     Syntax::Highlighter const* syntax_highlighter() const;