Replace freetype-rs with freetype (from servo) to match harfbuzz

[cormacrelf]

Probably best to depend on freetype -> servo-freetype-sys only. Replace the freetype-rs dependency, as I recall it had some iffy bugs and panics in its issue tracker and moreover I believe it may cause cargo to complain if you use harfbuzz/the servo freetype crates as well.

Originally posted by @cormacrelf in #136 (comment)

Relevant code that needs to be expanded into plain freetype calls:

tectonic/engine/src/xetex_aatfont.rs

Lines 871 to 897 in d3990d8

	thread_local!(static FREETYPE_LIBRARY: RefCell<FreeTypeLibrary> = RefCell::new(FreeTypeLibrary::init().unwrap()));
	// This needs to be linked from C++, hence extern "C"
	#[no_mangle]
	pub unsafe extern "C" fn getFileNameFromCTFont(
	mut ctFontRef: CTFontRef,
	mut index: *mut u32,
	) -> *mut i8 {
	let mut ix: i32 = -1;
	let mut ret: *mut libc::c_char = 0 as *mut libc::c_char;
	let urlRef = CTFontCopyAttribute(ctFontRef, kCTFontURLAttribute) as CFURLRef;
	if !urlRef.is_null() {
	let url = CFURL::wrap_under_create_rule(urlRef);
	if let Some(pathbuf) = url.to_path() {
	let ps_name1 = ct_font_get_postscript_name(ctFontRef, kCTFontPostScriptNameKey);
	let ps_name = Cow::from(&ps_name1);
	let mut i: isize = 0;
	while let Ok(face) = FREETYPE_LIBRARY.with(|l| l.borrow().new_face(&pathbuf, i)) {
	if let Some(ps_name2) = face.postscript_name() {
	if ps_name2 == ps_name {
	ix = i as i32;
	break;
	}
	}
	i += 1;
	}

Should be 'good first issue' but I can't tag. Also requires a mac to test.

[xcaptain]

Can you be more specific about how to fix it? I can give it a try if it's really an easy issue and you can guide me :)

[cormacrelf]

Not sure how much more specific I can be without doing it myself... Lines 871, 889-90 needs to do the same thing, except using raw freetype calls. It:

1. creates a FreeType library object technically line 871
2. Uses it to get a typeface from a filesystem path and an index (i)
3. Gets its postscript name (which includes Bold, etc) as a rust-comparable string so the code can cycle through the fonts at that path to find the one with the right postscript name. You may need to create a Cstr if FreeType gives you a null-terminated string.

https://docs.rs/freetype

Actually it's even easier. You're basically reverting this change:

46ca29c#diff-4f48babb53558bc10105fee1eb626783L1515-L1582 for these lines

tectonic/engine/src/xetex_aatfont.rs

Lines 1515 to 1583 in e0bb502

	pub unsafe extern "C" fn getFileNameFromCTFont(
	mut ctFontRef: CTFontRef,
	mut index: *mut uint32_t,
	) -> *mut libc::c_char {
	let mut ret: *mut libc::c_char = 0 as *mut libc::c_char;
	let mut url: CFURLRef = 0 as CFURLRef;
	url = CTFontCopyAttribute(ctFontRef, kCTFontURLAttribute) as CFURLRef;
	if !url.is_null() {
	let mut pathname: [UInt8; 1024] = [0; 1024];
	if CFURLGetFileSystemRepresentation(
	url,
	1i32 as Boolean,
	pathname.as_mut_ptr(),
	1024i32 as CFIndex,
	) != 0
	{
	let mut error: FT_Error = 0;
	let mut face: FT_Face = 0 as *mut FT_FaceRec_;
	*index = 0i32 as uint32_t;
	if gFreeTypeLibrary.is_null() {
	error = FT_Init_FreeType(&mut gFreeTypeLibrary);
	if error != 0 {
	panic!("FreeType initialization failed; error {}\x00", error);
	}
	}
	error = FT_New_Face(
	gFreeTypeLibrary,
	pathname.as_mut_ptr() as *mut libc::c_char,
	0i32 as FT_Long,
	&mut face,
	);
	if error == 0 {
	if (*face).num_faces > 1i32 as libc::c_long {
	let mut num_faces: libc::c_int = (*face).num_faces as libc::c_int;
	let mut ps_name1: *mut libc::c_char =
	getNameFromCTFont(ctFontRef, kCTFontPostScriptNameKey);
	let mut i: libc::c_int = 0;
	*index = -1i32 as uint32_t;
	FT_Done_Face(face);
	i = 0i32;
	while i < num_faces {
	error = FT_New_Face(
	gFreeTypeLibrary,
	pathname.as_mut_ptr() as *mut libc::c_char,
	i as FT_Long,
	&mut face,
	);
	if error == 0 {
	let mut ps_name2: *const libc::c_char = FT_Get_Postscript_Name(face);
	if streq_ptr(ps_name1, ps_name2) {
	*index = i as uint32_t;
	break;
	} else {
	FT_Done_Face(face);
	}
	}
	i += 1
	}
	free(ps_name1 as *mut libc::c_void);
	}
	}
	if *index != -1i32 as libc::c_uint {
	ret = strdup(pathname.as_mut_ptr() as *mut libc::c_char)
	}
	}
	CFRelease(url as CFTypeRef);
	}
	return ret;
	}