Implement FreeTypeNativeFont.glyph_h_advance

src/servo/text/native_font.rs

@@ -15,12 +15,18 @@ type NativeFont/& = quartz_native_font::QuartzNativeFont;
 #[cfg(target_os = "linux")]
 type NativeFont/& = ft_native_font::FreeTypeNativeFont;
 
+#[cfg(target_os = "macos")]
 fn with_test_native_font(f: fn@(NativeFont)) {
-    fail
+    quartz_native_font::with_test_native_font(f);
+}
+
+#[cfg(target_os = "linux")]
+fn with_test_native_font(f: fn@(nf: &NativeFont)) {
+    ft_native_font::with_test_native_font(f);
 }
 
 #[test]
-#[ignore]
+#[ignore(cfg(target_os = "macos"))]
 fn should_get_glyph_indexes() {
     with_test_native_font { |font|
         let idx = font.glyph_index('w');
@@ -29,10 +35,28 @@ fn should_get_glyph_indexes() {
 }
 
 #[test]
-#[ignore]
+#[ignore(cfg(target_os = "macos"))]
+fn should_return_none_glyph_index_for_bad_codepoints() {
+    with_test_native_font { |font|
+        let idx = font.glyph_index(0 as char);
+        assert idx == none;
+    }
+}
+
+#[test]
+#[ignore(cfg(target_os = "macos"))]
 fn should_get_glyph_h_advance() {
     with_test_native_font { |font|
         let adv = font.glyph_h_advance(40u);
-        assert adv == 15;
+        assert adv == some(15);
+    }
+}
+
+#[test]
+#[ignore(cfg(target_os = "macos"))]
+fn should_return_none_glyph_h_advance_for_bad_codepoints() {
+    with_test_native_font { |font|
+        let adv = font.glyph_h_advance(-1 as uint);
+        assert adv == none;
     }
 }

src/servo/text/native_font/ft_native_font.rs

@@ -1,16 +1,20 @@
-export FreeTypeNativeFont;
+export FreeTypeNativeFont, with_test_native_font;
 
 import vec_as_buf = vec::as_buf;
 import result::{result, ok, err};
 import ptr::{addr_of, null};
+import unsafe::reinterpret_cast;
 import glyph::GlyphIndex;
 import azure::freetype;
-import freetype::{ FT_Error, FT_Library, FT_Face, FT_Long };
+import freetype::{ FT_Error, FT_Library, FT_Face, FT_Long, FT_ULong, FT_UInt, FT_GlyphSlot };
 import freetype::bindgen::{
     FT_Init_FreeType,
     FT_Done_FreeType,
     FT_New_Memory_Face,
-    FT_Done_Face
+    FT_Done_Face,
+    FT_Get_Char_Index,
+    FT_Load_Glyph,
+    FT_Set_Char_Size
 };
 
 class FreeTypeNativeFont/& {
@@ -28,13 +32,36 @@ class FreeTypeNativeFont/& {
         }
     }
 
-    fn glyph_index(_codepoint: char) -> option<GlyphIndex> {
-        fail;
+    fn glyph_index(codepoint: char) -> option<GlyphIndex> {
+        assert self.face.is_not_null();
+        let idx = FT_Get_Char_Index(self.face, codepoint as FT_ULong);
+        ret if idx != 0 as FT_UInt {
+            some(idx as GlyphIndex)
+        } else {
+            #warn("Invalid codepoint: %?", codepoint);
+            none
+        };
     }
 
     // FIXME: What unit is this returning? Let's have a custom type
-    fn glyph_h_advance(_glyph: GlyphIndex) -> int {
-        fail;
+    fn glyph_h_advance(glyph: GlyphIndex) -> option<int> {
+        assert self.face.is_not_null();
+        let res =  FT_Load_Glyph(self.face, glyph as FT_UInt, 0);
+        if res.succeeded() {
+            unsafe {
+                let void_glyph = (*self.face).glyph;
+                let slot: FT_GlyphSlot = reinterpret_cast(void_glyph);
+                assert slot.is_not_null();
+                let advance = (*slot).metrics.horiAdvance;
+                #debug("h_advance for %? is %?", glyph, advance);
+                // FIXME: Dividing by 64 converts to pixels, which
+                // is not the unit we should be using
+                ret some((advance / 64) as int);
+            }
+        } else {
+            #warn("Unable to load glyph %?. reason: %?", glyph, res);
+            ret none;
+        }
     }
 }
 
@@ -44,6 +71,9 @@ fn create(lib: FT_Library, buf: &[u8]) -> result<FreeTypeNativeFont, ()> {
     ret vec_as_buf(*buf) {|cbuf|
         if FT_New_Memory_Face(lib, cbuf, (*buf).len() as FT_Long,
                               0 as FT_Long, addr_of(face)).succeeded() {
+            // FIXME: These values are placeholders
+            let res = FT_Set_Char_Size(face, 0, 20*64, 0, 72);
+            if !res.succeeded() { fail "unable to set font char size" }
             ok(FreeTypeNativeFont(face))
         } else {
             err(())
@@ -55,6 +85,18 @@ impl methods for FT_Error {
     fn succeeded() -> bool { self == 0 as FT_Error }
 }
 
+#[cfg(target_os = "linux")]
+fn with_test_native_font(f: fn@(nf: &NativeFont)) {
+    import font::test_font_bin;
+    import unwrap_result = result::unwrap;
+
+    with_lib { |lib|
+        let buf = test_font_bin();
+        let font = unwrap_result(create(lib, &buf));
+        f(&font);
+    }
+}
+
 #[cfg(test)]
 fn with_lib(f: fn@(FT_Library)) {
     let lib: FT_Library = null();

src/servo/text/native_font/quartz_native_font.rs

@@ -1,3 +1,5 @@
+export QuartzNativeFont, with_test_native_font;
+
 import glyph::GlyphIndex;
 
 class QuartzNativeFont/& {
@@ -10,7 +12,12 @@ class QuartzNativeFont/& {
     }
 
     // FIXME: What unit is this returning? Let's have a custom type
-    fn glyph_h_advance(_glyph: GlyphIndex) -> int {
+    fn glyph_h_advance(_glyph: GlyphIndex) -> option<int> {
         fail;
     }
 }
+
+#[cfg(target_os = "linux")]
+fn with_test_native_font(f: fn@(nf: &NativeFont)) {
+    fail
+}