Add Harfbuzz support

[Ghabry]

WIP PR to test harfbuzz shaping support :)

First I refactored the Font and Text Api: Font is now only responsible for rendering single glyphs (char32_t). For any high level usage the Text Api must be used.

The exception to "single glyph" is the shaping Api which takes a u32string because this conditionally converts codepoints depending on the shaping rules. When Harfbuzz is enabled the Text Api will automatically handle this.

A special case is Window_Message. It renders glyph-by-glyph instead of all-in-one-go. This requires usage of the low level Font Api directly because the shaping information must be known.

[Ghabry]

The Yume Nikki Online project is asking about Arabic text.

What impresses me here is that Harfbuzz can render right-to-left scripts correctly without changing a single line of code 🤔

[Ghabry]

Somebody asked about Times New Bastard. This is a font that makes every 7th character Sans Serif (Ligature magic).

When you count the glyphs you can see that it works. Though the font looks terrible. No good low res glyphs provided by the font:

[Ghabry]

Linking libretro on macOS is broken since a while. Fits with Harfbuzz as its the issue:

diff --git a/builds/cmake/Modules/FindHarfbuzz.cmake b/builds/cmake/Modules/FindHarfbuzz.cmake
index 1f5a1fd0..654600e0 100644
--- a/builds/cmake/Modules/FindHarfbuzz.cmake
+++ b/builds/cmake/Modules/FindHarfbuzz.cmake
@@ -64,6 +64,30 @@ if(HARFBUZZ_FOUND)
			INTERFACE_INCLUDE_DIRECTORIES "${HARFBUZZ_INCLUDE_DIRS}"
			INTERFACE_LINK_LIBRARIES Freetype::Freetype
			IMPORTED_LOCATION "${HARFBUZZ_LIBRARY}")
+
+		if(APPLE)
+			# Framework list taken from Harfbuzz CMakeLists
+			if(IOS)
+				find_library(COREFOUNDATION CoreFoundation REQUIRED)
+				find_library(CORETEXT CoreText REQUIRED)
+				find_library(COREGRAPHICS CoreGraphics REQUIRED)
+
+				set_property(TARGET Harfbuzz::Harfbuzz APPEND PROPERTY
+					INTERFACE_LINK_LIBRARIES ${COREFOUNDATION} ${CORETEXT}
+						${COREGRAPHICS})
+
+				mark_as_advanced(COREFOUNDATION)
+				mark_as_advanced(CORETEXT)
+				mark_as_advanced(COREGRAPHICS)
+			else()
+				find_library(APPLICATION_SERVICES ApplicationServices REQUIRED)
+
+				set_property(TARGET Harfbuzz::Harfbuzz APPEND PROPERTY
+					INTERFACE_LINK_LIBRARIES ${APPLICATION_SERVICES})
+
+				mark_as_advanced(APPLICATION_SERVICES)
+			endif()
+		endif()
	endif()
 endif()
 

[Ghabry]

Reran all the message tests of our TestGame for both with and without Freetype/Harfbuzz. Found one bug concerning the speed which is resolved now.

Ready to review. I consider this "kinda low risk" because except for "GetSize" the new code is only executed when a font is specified. The built-in font will not hit the new code.

[fdelapena]

s/ch/glyph/

[fdelapena]

The Yume Nikki Online project is asking about Arabic text.

What impresses me here is that Harfbuzz can render right-to-left scripts correctly without changing a single line of code thinking

Works great, adding a note regarding a comment in chat regarding limited height for drawing glyphs: the shadow in the Arabic script above shows it's cropped (16 px height limit), and this could limit Thai scripting and "Zalgo" text, but I think it's good enough as is until some user complains ^^.