Auto merge of #196 - zhuge:feat/directwrite, r=jdm

Feat/directwrite

1. Export hb-directwrite functions on windows
2. Export hb-ft function when feature build-native-freetype is on

harfbuzz-sys/Cargo.toml

@@ -31,10 +31,19 @@ core-graphics = "0.22"
 core-text = "19"
 foreign-types = "0.3"
 
+[target.'cfg(target_family = "windows")'.dependencies.winapi]
+version = "0.3"
+features = ["dwrite"]
+
 [target.'cfg(any(target_os = "android", all(unix, not(target_vendor = "apple"))))'.dependencies]
 freetype = { version = "0.7", default-features = false }
 
+[dependencies.freetype]
+version = "0.7"
+default-features = false
+optional = true
+
 [features]
 default = ["build-native-harfbuzz", "build-native-freetype"]
 build-native-harfbuzz = ["cc", "pkg-config"]
-build-native-freetype = ["freetype/freetype-sys"]
+build-native-freetype = ["freetype", "freetype/freetype-sys"]

harfbuzz-sys/build.rs

@@ -31,6 +31,10 @@ fn main() {
         cfg.define("HAVE_CORETEXT", "1");
     }
 
+    if target.contains("windows") {
+        cfg.define("HAVE_DIRECTWRITE", "1");
+    }
+
     if target.contains("windows-gnu") {
         cfg.flag("-Wa,-mbig-obj");
     }

harfbuzz-sys/src/directwrite.rs

@@ -0,0 +1,9 @@
+extern crate winapi;
+
+use hb_face_t;
+
+use self::winapi::um::dwrite::IDWriteFontFace;
+
+extern "C" {
+    pub fn hb_directwrite_face_create(font_face: *mut IDWriteFontFace) -> *mut hb_face_t;
+}

harfbuzz-sys/src/lib.rs

@@ -1,10 +1,13 @@
-#[cfg(any(target_os = "android", all(unix, not(target_vendor = "apple"))))]
+#[cfg(any(target_os = "android", all(unix, not(target_vendor = "apple")), feature="build-native-freetype"))]
 extern crate freetype;
 
 #[cfg(target_vendor = "apple")]
 pub mod coretext;
 
-#[cfg(any(target_os = "android", all(unix, not(target_vendor = "apple"))))]
+#[cfg(target_family = "windows")]
+pub mod directwrite;
+
+#[cfg(any(target_os = "android", all(unix, not(target_vendor = "apple")), feature="build-native-freetype"))]
 extern "C" {
     pub fn hb_ft_font_create_referenced(face: freetype::freetype::FT_Face) -> *mut hb_font_t;
 }