Perfect FreeType-based outlines for DynamicFonts

- Implement outlines based on FreeType Stroker API. This allows
  artifact-free results, similar to what you will see in Web or any text
  editing tools. Outline is a part of DynamicFont rather than Label,
  because outlines have to be baked into the font's atlas. Font has a
  default outline_color and a Label can specify font_outline_modulator
  that will be multiplied with the Font's color to get the final result.

- draw_char now has to be called twice to fully render a text - first
  with p_outline == true for each character and then with
  p_outline == false for each character.

- Number of draw-calls is reduced from 5 to 2 per outlined character.

- Overall cleanup of DynamicFont code, extracted duplicated code pieces
  into separate methods.

- The change is backward-compatible - Labels still have outline
  properties that work exactly as they worked before.

Closes #16279.

1 files changed, 2 insertions, 1 deletions

diff --git a/scene/gui/item_list.cpp b/scene/gui/item_list.cpp
index 511dc248a..602b15144 100644
--- a/scene/gui/item_list.cpp
+++ b/scene/gui/item_list.cpp
@@ -1121,6 +1121,7 @@ void ItemList::_notification(int p_what) {
 					text_ofs += base_ofs;
 					text_ofs += items[i].rect_cache.position;
 
+					FontDrawer drawer(font, Color(1, 1, 1));
 					for (int j = 0; j < ss; j++) {
 
 						if (j == line_limit_cache[line]) {
@@ -1129,7 +1130,7 @@ void ItemList::_notification(int p_what) {
 							if (line >= max_text_lines)
 								break;
 						}
-						ofs += font->draw_char(get_canvas_item(), text_ofs + Vector2(ofs + (max_len - line_size_cache[line]) / 2, line * (font_height + line_separation)).floor(), items[i].text[j], items[i].text[j + 1], modulate);
+						ofs += drawer.draw_char(get_canvas_item(), text_ofs + Vector2(ofs + (max_len - line_size_cache[line]) / 2, line * (font_height + line_separation)).floor(), items[i].text[j], items[i].text[j + 1], modulate);
 					}
 
 					//special multiline mode