LibGUI: Add underlines to highlighting

Author: oriko1010

Libraries/LibGUI/CppSyntaxHighlighter.cpp

@@ -56,7 +56,7 @@ void CppSyntaxHighlighter::rehighlight()
         span.color = style.color;
         span.font = style.font;
         span.is_skippable = token.m_type == CppToken::Type::Whitespace;
-        span.data = (void*)token.m_type;
+        span.data = reinterpret_cast<void*>(token.m_type);
         spans.append(span);
     }
     m_editor->document().set_spans(spans);

Libraries/LibGUI/CppSyntaxHighlighter.h

@@ -7,8 +7,9 @@ namespace GUI {
 class CppSyntaxHighlighter final : public SyntaxHighlighter {
 public:
     CppSyntaxHighlighter() {}
-
     virtual ~CppSyntaxHighlighter() override;
+
+    virtual SyntaxLanguage language() const override { return SyntaxLanguage::Cpp; }
     virtual void rehighlight() override;
     virtual void highlight_matching_token_pair() override;
 };

Libraries/LibGUI/SyntaxHighlighter.h

@@ -6,13 +6,19 @@
 
 namespace GUI {
 
+enum class SyntaxLanguage {
+    PlainText,
+    Cpp
+};
+
 class SyntaxHighlighter {
     AK_MAKE_NONCOPYABLE(SyntaxHighlighter);
     AK_MAKE_NONMOVABLE(SyntaxHighlighter);
 
 public:
     virtual ~SyntaxHighlighter();
 
+    virtual SyntaxLanguage language() const = 0;
     virtual void rehighlight() = 0;
     virtual void highlight_matching_token_pair() = 0;
 

Libraries/LibGUI/TextDocument.h

@@ -46,6 +46,7 @@ struct TextDocumentSpan {
     Color color;
     Optional<Color> background_color;
     bool is_skippable { false };
+    bool is_underlined { false };
     const Gfx::Font* font { nullptr };
     void* data { nullptr };
 };
@@ -87,6 +88,7 @@ class TextDocument : public RefCounted<TextDocument> {
     NonnullOwnPtrVector<TextDocumentLine>& lines() { return m_lines; }
 
     bool has_spans() const { return !m_spans.is_empty(); }
+    Vector<TextDocumentSpan>& spans() { return m_spans; }
     const Vector<TextDocumentSpan>& spans() const { return m_spans; }
     void set_span_at_index(size_t index, TextDocumentSpan span) { m_spans[index] = move(span); }
 

Libraries/LibGUI/TextEditor.cpp

@@ -425,6 +425,7 @@ void TextEditor::paint_event(PaintEvent& event)
                     const Gfx::Font* font = &this->font();
                     Color color;
                     Optional<Color> background_color;
+                    bool underline = false;
                     TextPosition physical_position(line_index, start_of_visual_line + i);
                     // FIXME: This is *horribly* inefficient.
                     for (auto& span : document().spans()) {
@@ -434,11 +435,15 @@ void TextEditor::paint_event(PaintEvent& event)
                         if (span.font)
                             font = span.font;
                         background_color = span.background_color;
+                        underline = span.is_underlined;
                         break;
                     }
                     if (background_color.has_value())
                         painter.fill_rect(character_rect, background_color.value());
                     painter.draw_text(character_rect, visual_line_text.substring_view(i, 1), *font, m_text_alignment, color);
+                    if (underline) {
+                        painter.draw_line(character_rect.bottom_left().translated(0, 1), character_rect.bottom_right().translated(0, 1), color);
+                    }
                     character_rect.move_by(advance, 0);
                 }
             }
@@ -1490,6 +1495,14 @@ void TextEditor::flush_pending_change_notification_if_needed()
     m_has_pending_change_notification = false;
 }
 
+const SyntaxHighlighter* TextEditor::syntax_highlighter() const
+{
+    if (m_highlighter)
+        return m_highlighter.ptr();
+    else
+        return nullptr;
+}
+
 void TextEditor::set_syntax_highlighter(OwnPtr<SyntaxHighlighter> highlighter)
 {
     if (m_highlighter)

Libraries/LibGUI/TextEditor.h

@@ -127,6 +127,7 @@ class TextEditor
     void set_cursor(size_t line, size_t column);
     void set_cursor(const TextPosition&);
 
+    const SyntaxHighlighter* syntax_highlighter() const;
     void set_syntax_highlighter(OwnPtr<SyntaxHighlighter>);
 
 protected: