LibVT: only use default bold font if it's the same size as our font

When the new font is a different size, just use that font for bold
glyphs as well.  It would be nice to find a matching bold version of
the new font automatically in the future.

Libraries/LibVT/TerminalWidget.cpp

@@ -340,7 +340,7 @@ void TerminalWidget::paint_event(GPaintEvent& event)
  painter.draw_glyph_or_emoji(
  character_rect.location(),
  codepoint,
- attribute.flags & VT::Attribute::Bold ? Font::default_bold_fixed_width_font() : font(),
+ attribute.flags & VT::Attribute::Bold ? bold_font() : font(),
  lookup_color(should_reverse_fill_for_cursor_or_selection ? attribute.background_color : attribute.foreground_color));
  }
  }
@@ -667,6 +667,15 @@ void TerminalWidget::did_change_font()
 {
  GFrame::did_change_font();
  m_line_height = font().glyph_height() + m_line_spacing;
+
+ // TODO: try to find a bold version of the new font (e.g. CsillaThin7x10 -> CsillaBold7x10)
+ const Font& bold_font = Font::default_bold_fixed_width_font();
+
+ if (bold_font.glyph_height() == font().glyph_height() && bold_font.glyph_width(' ') == font().glyph_width(' '))
+ m_bold_font = &bold_font;
+ else
+ m_bold_font = font();
+
  if (!size().is_empty())
  relayout(size());
 }

Libraries/LibVT/TerminalWidget.h

@@ -32,6 +32,8 @@ class TerminalWidget final : public GFrame
 
  void apply_size_increments_to_window(GWindow&);
 
+ const Font& bold_font() const { return *m_bold_font; }
+
  void set_opacity(u8);
  float opacity() { return m_opacity; };
  bool should_beep() { return m_should_beep; }
@@ -120,6 +122,8 @@ class TerminalWidget final : public GFrame
  bool m_cursor_blink_state { true };
  bool m_automatic_size_policy { false };
 
+ RefPtr<Font> m_bold_font;
+
  int m_glyph_width { 0 };
 
  RefPtr<CTimer> m_cursor_blink_timer;