Implement kerning support for linux/android. Improves some wikipedia issues (#2554).

6 files changed, 54 insertions, 6 deletions

diff --git a/src/components/gfx/font.rs b/src/components/gfx/font.rs
index a17bf199979..2c902b8a2bb 100644
--- a/src/components/gfx/font.rs
+++ b/src/components/gfx/font.rs
@@ -36,6 +36,7 @@ pub trait FontHandleMethods {
 
     fn glyph_index(&self, codepoint: char) -> Option<GlyphId>;
     fn glyph_h_advance(&self, GlyphId) -> Option<FractionalPixel>;
+    fn glyph_h_kerning(&self, GlyphId, GlyphId) -> FractionalPixel;
     fn get_metrics(&self) -> FontMetrics;
     fn get_table_for_tag(&self, FontTableTag) -> Option<FontTable>;
 }
@@ -148,6 +149,10 @@ impl Font {
         self.handle.glyph_index(codepoint)
     }
 
+    pub fn glyph_h_kerning(&mut self, first_glyph: GlyphId, second_glyph: GlyphId) -> FractionalPixel {
+        self.handle.glyph_h_kerning(first_glyph, second_glyph)
+    }
+
     pub fn glyph_h_advance(&mut self, glyph: GlyphId) -> FractionalPixel {
         let handle = &self.handle;
         self.glyph_advance_cache.find_or_create(&glyph, |glyph| {
diff --git a/src/components/gfx/platform/android/font.rs b/src/components/gfx/platform/android/font.rs
index 9e393733c69..989dda4a718 100644
--- a/src/components/gfx/platform/android/font.rs
+++ b/src/components/gfx/platform/android/font.rs
@@ -16,12 +16,12 @@ use platform::font_template::FontTemplateData;
 
 use freetype::freetype::{FT_Get_Char_Index, FT_Get_Postscript_Name};
 use freetype::freetype::{FT_Load_Glyph, FT_Set_Char_Size};
-use freetype::freetype::{FT_Get_Sfnt_Table};
+use freetype::freetype::{FT_Get_Kerning, FT_Get_Sfnt_Table};
 use freetype::freetype::{FT_New_Memory_Face, FT_Done_Face};
 use freetype::freetype::{FTErrorMethods, FT_F26Dot6, FT_Face, FT_FaceRec};
 use freetype::freetype::{FT_GlyphSlot, FT_Library, FT_Long, FT_ULong};
-use freetype::freetype::{FT_STYLE_FLAG_ITALIC, FT_STYLE_FLAG_BOLD};
-use freetype::freetype::{FT_SizeRec, FT_UInt, FT_Size_Metrics};
+use freetype::freetype::{FT_KERNING_DEFAULT, FT_STYLE_FLAG_ITALIC, FT_STYLE_FLAG_BOLD};
+use freetype::freetype::{FT_SizeRec, FT_UInt, FT_Size_Metrics, struct_FT_Vector_};
 use freetype::freetype::{ft_sfnt_os2};
 use freetype::tt_os2::TT_OS2;
 
@@ -171,6 +171,16 @@ impl FontHandleMethods for FontHandle {
         }
     }
 
+    fn glyph_h_kerning(&self, first_glyph: GlyphId, second_glyph: GlyphId)
+                        -> FractionalPixel {
+        assert!(self.face.is_not_null());
+        let delta = struct_FT_Vector_ { x: 0, y: 0 };
+        unsafe {
+            FT_Get_Kerning(self.face, first_glyph, second_glyph, FT_KERNING_DEFAULT, &delta);
+        }
+        fixed_to_float_ft(delta.x as i32)
+    }
+
     fn glyph_h_advance(&self,
                            glyph: GlyphId) -> Option<FractionalPixel> {
         assert!(self.face.is_not_null());
diff --git a/src/components/gfx/platform/linux/font.rs b/src/components/gfx/platform/linux/font.rs
index 9e393733c69..989dda4a718 100644
--- a/src/components/gfx/platform/linux/font.rs
+++ b/src/components/gfx/platform/linux/font.rs
@@ -16,12 +16,12 @@ use platform::font_template::FontTemplateData;
 
 use freetype::freetype::{FT_Get_Char_Index, FT_Get_Postscript_Name};
 use freetype::freetype::{FT_Load_Glyph, FT_Set_Char_Size};
-use freetype::freetype::{FT_Get_Sfnt_Table};
+use freetype::freetype::{FT_Get_Kerning, FT_Get_Sfnt_Table};
 use freetype::freetype::{FT_New_Memory_Face, FT_Done_Face};
 use freetype::freetype::{FTErrorMethods, FT_F26Dot6, FT_Face, FT_FaceRec};
 use freetype::freetype::{FT_GlyphSlot, FT_Library, FT_Long, FT_ULong};
-use freetype::freetype::{FT_STYLE_FLAG_ITALIC, FT_STYLE_FLAG_BOLD};
-use freetype::freetype::{FT_SizeRec, FT_UInt, FT_Size_Metrics};
+use freetype::freetype::{FT_KERNING_DEFAULT, FT_STYLE_FLAG_ITALIC, FT_STYLE_FLAG_BOLD};
+use freetype::freetype::{FT_SizeRec, FT_UInt, FT_Size_Metrics, struct_FT_Vector_};
 use freetype::freetype::{ft_sfnt_os2};
 use freetype::tt_os2::TT_OS2;
 
@@ -171,6 +171,16 @@ impl FontHandleMethods for FontHandle {
         }
     }
 
+    fn glyph_h_kerning(&self, first_glyph: GlyphId, second_glyph: GlyphId)
+                        -> FractionalPixel {
+        assert!(self.face.is_not_null());
+        let delta = struct_FT_Vector_ { x: 0, y: 0 };
+        unsafe {
+            FT_Get_Kerning(self.face, first_glyph, second_glyph, FT_KERNING_DEFAULT, &delta);
+        }
+        fixed_to_float_ft(delta.x as i32)
+    }
+
     fn glyph_h_advance(&self,
                            glyph: GlyphId) -> Option<FractionalPixel> {
         assert!(self.face.is_not_null());
diff --git a/src/components/gfx/platform/macos/font.rs b/src/components/gfx/platform/macos/font.rs
index 26209abb9d9..9ff32f0dee9 100644
--- a/src/components/gfx/platform/macos/font.rs
+++ b/src/components/gfx/platform/macos/font.rs
@@ -124,6 +124,12 @@ impl FontHandleMethods for FontHandle {
         return Some(glyphs[0] as GlyphId);
     }
 
+    fn glyph_h_kerning(&self, _first_glyph: GlyphId, _second_glyph: GlyphId)
+                        -> FractionalPixel {
+        // TODO: Implement on mac
+        0.0
+    }
+
     fn glyph_h_advance(&self, glyph: GlyphId) -> Option<FractionalPixel> {
         let glyphs = [glyph as CGGlyph];
         let advance = self.ctfont.get_advances_for_glyphs(kCTFontDefaultOrientation,
diff --git a/src/components/gfx/text/shaping/harfbuzz.rs b/src/components/gfx/text/shaping/harfbuzz.rs
index e028ae8dac2..c495c3e26be 100644
--- a/src/components/gfx/text/shaping/harfbuzz.rs
+++ b/src/components/gfx/text/shaping/harfbuzz.rs
@@ -27,6 +27,7 @@ use harfbuzz::{hb_font_funcs_create};
 use harfbuzz::{hb_font_funcs_destroy};
 use harfbuzz::{hb_font_funcs_set_glyph_func};
 use harfbuzz::{hb_font_funcs_set_glyph_h_advance_func};
+use harfbuzz::{hb_font_funcs_set_glyph_h_kerning_func};
 use harfbuzz::{hb_font_funcs_t, hb_buffer_t, hb_codepoint_t};
 use harfbuzz::{hb_font_set_funcs};
 use harfbuzz::{hb_font_set_ppem};
@@ -176,6 +177,7 @@ impl Shaper {
             let hb_funcs: *hb_font_funcs_t = hb_font_funcs_create();
             hb_font_funcs_set_glyph_func(hb_funcs, glyph_func, null(), None);
             hb_font_funcs_set_glyph_h_advance_func(hb_funcs, glyph_h_advance_func, null(), None);
+            hb_font_funcs_set_glyph_h_kerning_func(hb_funcs, glyph_h_kerning_func, null(), null());
             hb_font_set_funcs(hb_font, hb_funcs, font_ptr as *c_void, None);
 
             Shaper {
@@ -487,6 +489,21 @@ extern fn glyph_h_advance_func(_: *hb_font_t,
     }
 }
 
+extern fn glyph_h_kerning_func(_: *hb_font_t,
+                               font_data: *c_void,
+                               first_glyph: hb_codepoint_t,
+                               second_glyph: hb_codepoint_t,
+                               _: *c_void)
+                            -> hb_position_t {
+    let font: *mut Font = font_data as *mut Font;
+    assert!(font.is_not_null());
+
+    unsafe {
+        let advance = (*font).glyph_h_kerning(first_glyph as GlyphId, second_glyph as GlyphId);
+        Shaper::float_to_fixed(advance)
+    }
+}
+
 // Callback to get a font table out of a font.
 extern fn get_font_table_func(_: *hb_face_t, tag: hb_tag_t, user_data: *c_void) -> *hb_blob_t {
     unsafe {
diff --git a/src/support/harfbuzz/rust-harfbuzz b/src/support/harfbuzz/rust-harfbuzz
-Subproject 3763b41bc060731b7644e83f923ec69ca7c0c20
+Subproject db93ee4a61154ded598e6560df78a9e0e164c81