TextEditor: Visualize leading whitespace

2 files changed, 27 insertions, 0 deletions

diff --git a/Userland/Libraries/LibGUI/TextEditor.cpp b/Userland/Libraries/LibGUI/TextEditor.cpp
index 8e39173d2c..b9d804b944 100644
--- a/Userland/Libraries/LibGUI/TextEditor.cpp
+++ b/Userland/Libraries/LibGUI/TextEditor.cpp
@@ -640,6 +640,21 @@ void TextEditor::paint_event(PaintEvent& event)
                 }
             }
 
+            if (m_visualize_leading_whitespace && line.leading_spaces() > 0) {
+                size_t physical_column = line.leading_spaces();
+                size_t end_of_leading_whitespace = (start_of_visual_line + physical_column);
+                size_t end_of_visual_line = (start_of_visual_line + visual_line_text.length());
+                if (end_of_leading_whitespace < end_of_visual_line) {
+                    Gfx::IntRect whitespace_rect {
+                        content_x_for_position({ line_index, start_of_visual_line }),
+                        visual_line_rect.y(),
+                        font().width(visual_line_text.substring_view(0, end_of_leading_whitespace)),
+                        visual_line_rect.height()
+                    };
+                    painter.fill_rect_with_dither_pattern(whitespace_rect, Color(), Color(192, 255, 192));
+                }
+            }
+
             if (physical_line_has_selection) {
                 size_t start_of_selection_within_visual_line = (size_t)max(0, (int)selection_start_column_within_line - (int)start_of_visual_line);
                 size_t end_of_selection_within_visual_line = selection_end_column_within_line - start_of_visual_line;
@@ -1764,6 +1779,14 @@ void TextEditor::set_visualize_trailing_whitespace(bool enabled)
     update();
 }
 
+void TextEditor::set_visualize_leading_whitespace(bool enabled)
+{
+    if (m_visualize_leading_whitespace == enabled)
+        return;
+    m_visualize_leading_whitespace = enabled;
+    update();
+}
+
 void TextEditor::set_should_autocomplete_automatically(bool value)
 {
     if (value == should_autocomplete_automatically())
diff --git a/Userland/Libraries/LibGUI/TextEditor.h b/Userland/Libraries/LibGUI/TextEditor.h
index a841dd0982..3abb87b1d6 100644
--- a/Userland/Libraries/LibGUI/TextEditor.h
+++ b/Userland/Libraries/LibGUI/TextEditor.h
@@ -81,6 +81,9 @@ public:
     void set_visualize_trailing_whitespace(bool);
     bool visualize_trailing_whitespace() const { return m_visualize_trailing_whitespace; }
 
+    void set_visualize_leading_whitespace(bool);
+    bool visualize_leading_whitespace() const { return m_visualize_leading_whitespace; }
+
     virtual bool is_automatic_indentation_enabled() const final { return m_automatic_indentation_enabled; }
     void set_automatic_indentation_enabled(bool enabled) { m_automatic_indentation_enabled = enabled; }
 
@@ -319,6 +322,7 @@ private:
     bool m_automatic_indentation_enabled { false };
     WrappingMode m_wrapping_mode { WrappingMode::NoWrap };
     bool m_visualize_trailing_whitespace { true };
+    bool m_visualize_leading_whitespace { false };
     int m_line_spacing { 4 };
     size_t m_soft_tab_width { 4 };
     int m_horizontal_content_padding { 3 };