DirectWrite font backend for Windows

components/gfx/Cargo.toml

@@ -53,15 +53,12 @@ core-foundation = "0.2"
 core-graphics = "0.4"
 core-text = "2.0"
 
-[target.'cfg(any(target_os = "linux", target_os = "android", target_os = "windows"))'.dependencies]
-freetype = {git = "https://github.com/servo/rust-freetype"}
-
 [target.'cfg(any(target_os = "linux", target_os = "android"))'.dependencies]
+freetype = {git = "https://github.com/servo/rust-freetype"}
 servo-fontconfig = "0.2.1"
 
 [target.'cfg(any(target_arch = "x86_64", target_arch = "aarch64"))'.dependencies]
 simd = {git = "https://github.com/huonw/simd"}
 
 [target.'cfg(target_os = "windows")'.dependencies]
-winapi = "0.2"
-gdi32-sys = "0.2"
+dwrote = {git = "https://github.com/vvuk/dwrote-rs"}

components/gfx/lib.rs

@@ -29,8 +29,7 @@ extern crate bitflags;
 #[cfg(target_os = "macos")] extern crate core_text;
 
 // Windows-specific library dependencies
-#[cfg(target_os = "windows")] extern crate gdi32;
-#[cfg(target_os = "windows")] extern crate winapi;
+#[cfg(target_os = "windows")] extern crate dwrote;
 
 extern crate euclid;
 extern crate fnv;
@@ -38,10 +37,11 @@ extern crate fnv;
 // Platforms that use Freetype/Fontconfig library dependencies
 #[cfg(any(target_os = "linux", target_os = "android"))]
 extern crate fontconfig;
-extern crate fontsan;
-#[cfg(any(target_os = "linux", target_os = "android", target_os = "windows"))]
+#[cfg(any(target_os = "linux", target_os = "android"))]
 extern crate freetype;
 
+extern crate fontsan;
+
 extern crate gfx_traits;
 
 // Eventually we would like the shaper to be pluggable, as many operating systems have their own

components/gfx/platform/mod.rs

@@ -2,19 +2,19 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-#[cfg(any(target_os = "linux", target_os = "android", target_os = "windows"))]
+#[cfg(any(target_os = "linux", target_os = "android"))]
 pub use platform::freetype::{font, font_context};
 
 #[cfg(any(target_os = "linux", target_os = "android"))]
 pub use platform::freetype::{font_list, font_template};
 
 #[cfg(target_os = "windows")]
-pub use platform::windows::{font_list, font_template};
+pub use platform::windows::{font, font_context, font_list, font_template};
 
 #[cfg(target_os = "macos")]
 pub use platform::macos::{font, font_context, font_list, font_template};
 
-#[cfg(any(target_os = "linux", target_os = "android", target_os = "windows"))]
+#[cfg(any(target_os = "linux", target_os = "android"))]
 mod freetype {
     use libc::c_char;
     use std::ffi::CStr;
@@ -46,6 +46,8 @@ mod macos {
 
 #[cfg(target_os = "windows")]
 mod windows {
+    pub mod font;
+    pub mod font_context;
     pub mod font_list;
     pub mod font_template;
 }

components/gfx/platform/windows/font.rs

@@ -0,0 +1,204 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// NOTE: https://www.chromium.org/directwrite-font-proxy has useful
+// information for an approach that we'll likely need to take when the
+// renderer moves to a sandboxed process.
+
+use app_units::Au;
+use font::{FontHandleMethods, FontMetrics, FontTableMethods};
+use font::{FontTableTag, FractionalPixel};
+use platform::font_template::{FontTemplateData};
+use platform::windows::font_list::{font_from_atom};
+use platform::windows::font_context::{FontContextHandle};
+use std::sync::Arc;
+use style::computed_values::{font_stretch, font_weight};
+use text::glyph::GlyphId;
+use dwrote::{Font, FontFace};
+use dwrote::{FontWeight, FontStretch, FontStyle};
+
+// 1em = 12pt = 16px, assuming 72 points per inch and 96 px per inch
+fn pt_to_px(pt: f64) -> f64 { pt / 72. * 96. }
+fn em_to_px(em: f64) -> f64 { em * 16. }
+fn au_from_em(em: f64) -> Au { Au::from_f64_px(em_to_px(em)) }
+fn au_from_pt(pt: f64) -> Au { Au::from_f64_px(pt_to_px(pt)) }
+
+pub struct FontTable {
+    data: Vec<u8>,
+}
+
+impl FontTable {
+    pub fn wrap(data: &[u8]) -> FontTable {
+        FontTable { data: data.to_vec() }
+    }
+}
+
+impl FontTableMethods for FontTable {
+    fn buffer(&self) -> &[u8] {
+        &self.data
+    }
+}
+
+#[derive(Debug)]
+pub struct FontHandle {
+    font_data: Arc<FontTemplateData>,
+    font: Font,
+    face: FontFace,
+    em_size: f32,
+    du_per_em: f32,
+    du_to_px: f32,
+    scaled_du_to_px: f32,
+}
+
+impl FontHandle {
+}
+
+impl FontHandleMethods for FontHandle {
+    fn new_from_template(_: &FontContextHandle, template: Arc<FontTemplateData>, pt_size: Option<Au>)
+                         -> Result<Self, ()>
+    {
+        if let Some(_) = template.bytes {
+            // FIXME we should load from template.bytes
+            Err(())
+        } else {
+            let font = font_from_atom(&template.identifier);
+            let face = font.create_font_face();
+
+            let pt_size = pt_size.unwrap_or(au_from_pt(12.));
+            let du_per_em = face.metrics().designUnitsPerEm as f32;
+
+            let em_size = pt_size.to_f32_px() / 16.;
+            let design_units_per_pixel = du_per_em / 16.;
+
+            let design_units_to_pixels = 1. / design_units_per_pixel;
+            let scaled_design_units_to_pixels = em_size / design_units_per_pixel;
+
+            Ok(FontHandle {
+                font_data: template.clone(),
+                font: font,
+                face: face,
+                em_size: em_size,
+                du_per_em: du_per_em,
+                du_to_px: design_units_to_pixels,
+                scaled_du_to_px: scaled_design_units_to_pixels,
+            })
+        }
+    }
+
+    fn template(&self) -> Arc<FontTemplateData> {
+        self.font_data.clone()
+    }
+
+    fn family_name(&self) -> String {
+        self.font.family_name()
+    }
+
+    fn face_name(&self) -> String {
+        self.font.face_name()
+    }
+
+    fn is_italic(&self) -> bool {
+        match self.font.style() {
+            FontStyle::Normal => false,
+            FontStyle::Oblique | FontStyle::Italic => true,
+        }
+    }
+
+    fn boldness(&self) -> font_weight::T {
+        match self.font.weight() {
+            FontWeight::Thin => font_weight::T::Weight100,
+            FontWeight::ExtraLight => font_weight::T::Weight200,
+            FontWeight::Light => font_weight::T::Weight300,
+            // slightly lighter gray
+            FontWeight::SemiLight => font_weight::T::Weight300,
+            FontWeight::Regular => font_weight::T::Weight400,
+            FontWeight::Medium => font_weight::T::Weight500,
+            FontWeight::SemiBold => font_weight::T::Weight600,
+            FontWeight::Bold => font_weight::T::Weight700,
+            FontWeight::ExtraBold => font_weight::T::Weight800,
+            FontWeight::Black => font_weight::T::Weight900,
+            // slightly blacker black
+            FontWeight::ExtraBlack => font_weight::T::Weight900,
+        }
+    }
+
+    fn stretchiness(&self) -> font_stretch::T {
+        match self.font.stretch() {
+            FontStretch::Undefined => font_stretch::T::normal,
+            FontStretch::UltraCondensed => font_stretch::T::ultra_condensed,
+            FontStretch::ExtraCondensed => font_stretch::T::extra_condensed,
+            FontStretch::Condensed => font_stretch::T::condensed,
+            FontStretch::SemiCondensed => font_stretch::T::semi_condensed,
+            FontStretch::Normal => font_stretch::T::normal,
+            FontStretch::SemiExpanded => font_stretch::T::semi_expanded,
+            FontStretch::Expanded => font_stretch::T::expanded,
+            FontStretch::ExtraExpanded => font_stretch::T::extra_expanded,
+            FontStretch::UltraExpanded => font_stretch::T::ultra_expanded,
+        }
+    }
+
+    fn glyph_index(&self, codepoint: char) -> Option<GlyphId> {
+        let glyph = self.face.get_glyph_indices(&[codepoint as u32])[0];
+        if glyph == 0 {
+            return None;
+        }
+        Some(glyph as GlyphId)
+    }
+
+    fn glyph_h_advance(&self, glyph: GlyphId) -> Option<FractionalPixel> {
+        if glyph == 0 {
+            return None;
+        }
+
+        let gm = self.face.get_design_glyph_metrics(&[glyph as u16], false)[0];
+        let f = (gm.advanceWidth as f32 * self.scaled_du_to_px) as FractionalPixel;
+
+        Some(f)
+    }
+
+    /// Can this font do basic horizontal LTR shaping without Harfbuzz?
+    fn can_do_fast_shaping(&self) -> bool {
+        // TODO copy CachedKernTable from the MacOS X implementation to
+        // somehwere global and use it here.  We could also implement the
+        // IDirectWriteFontFace1 interface and use the glyph kerning pair
+        // methods there.
+        false
+    }
+
+    fn glyph_h_kerning(&self, _: GlyphId, _: GlyphId) -> FractionalPixel {
+        0.0
+    }
+
+    fn metrics(&self) -> FontMetrics {
+        let dm = self.face.metrics();
+
+        let au_from_du = |du| -> Au { Au::from_f32_px(du as f32 * self.du_to_px) };
+        let au_from_du_s = |du| -> Au { Au:: from_f32_px(du as f32 * self.scaled_du_to_px) };
+
+        // anything that we calculate and don't just pull out of self.face.metrics
+        // is pulled out here for clarity
+        let leading = dm.ascent - dm.capHeight;
+        
+        let metrics = FontMetrics {
+            underline_size:   au_from_du(dm.underlineThickness as i32),
+            underline_offset: au_from_du_s(dm.underlinePosition as i32),
+            strikeout_size:   au_from_du(dm.strikethroughThickness as i32),
+            strikeout_offset: au_from_du_s(dm.strikethroughPosition as i32),
+            leading:          au_from_du_s(leading as i32),
+            x_height:         au_from_du_s(dm.xHeight as i32),
+            em_size:          au_from_em(self.em_size as f64),
+            ascent:           au_from_du_s(dm.ascent as i32),
+            descent:          au_from_du_s(dm.descent as i32),
+            max_advance:      au_from_pt(0.0), // FIXME
+            average_advance:  au_from_pt(0.0), // FIXME
+            line_gap:         au_from_du(dm.lineGap as i32),
+        };
+        debug!("Font metrics (@{} pt): {:?}", self.em_size * 12., metrics);
+        metrics
+    }
+
+    fn table_for_tag(&self, tag: FontTableTag) -> Option<FontTable> {
+        self.face.get_font_table(tag).map(|bytes| FontTable { data: bytes })
+    }
+}

components/gfx/platform/windows/font_context.rs

@@ -0,0 +1,21 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use heapsize::HeapSizeOf;
+
+#[derive(Clone, Debug)]
+pub struct FontContextHandle;
+
+impl FontContextHandle {
+    // *shrug*
+    pub fn new() -> FontContextHandle {
+        FontContextHandle {}
+    }
+}
+
+impl HeapSizeOf for FontContextHandle {
+    fn heap_size_of_children(&self) -> usize {
+        0
+    }
+}

components/gfx/platform/windows/font_list.rs

@@ -2,73 +2,70 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use gdi32;
-use std::ffi::OsString;
-use std::os::windows::ffi::OsStringExt;
-use std::ptr;
-use winapi::{LOGFONTW, LPARAM, OUT_TT_ONLY_PRECIS, VOID};
-use winapi::{c_int, DWORD, LF_FACESIZE};
+use dwrote::{Font, FontDescriptor, FontCollection};
+use servo_atoms::Atom;
+use std::collections::HashMap;
+use std::sync::Mutex;
+use std::sync::atomic::{Ordering, AtomicUsize};
+
+lazy_static! {
+    static ref FONT_ATOM_COUNTER: AtomicUsize = AtomicUsize::new(1);
+    static ref FONT_ATOM_MAP: Mutex<HashMap<Atom, FontDescriptor>> = Mutex::new(HashMap::new());
+}
 
 pub static SANS_SERIF_FONT_FAMILY: &'static str = "Arial";
 
 pub fn system_default_family(_: &str) -> Option<String> {
-    None
+    Some("Verdana".to_owned())
 }
 
 pub fn last_resort_font_families() -> Vec<String> {
     vec!("Arial".to_owned())
 }
 
-unsafe extern "system" fn enum_font_callback(lpelfe: *const LOGFONTW,
-                                             _: *const VOID,
-                                             _: DWORD,
-                                             lparam: LPARAM) -> c_int {
-    let name = (*lpelfe).lfFaceName;
-    let term_pos = name.iter().position(|c| *c == 0).unwrap();
-    let name = OsString::from_wide(&name[0..term_pos]).into_string().unwrap();
-
-    let fonts = lparam as *mut Vec<String>;
-    let fonts = &mut *fonts;
-    fonts.push(name);
-
-    1
-}
-
 pub fn for_each_available_family<F>(mut callback: F) where F: FnMut(String) {
-    let mut fonts = Vec::new();
-
-    let mut config = LOGFONTW {
-        lfHeight: 0,
-        lfWidth: 0,
-        lfEscapement: 0,
-        lfOrientation: 0,
-        lfWeight: 0,
-        lfItalic: 0,
-        lfUnderline: 0,
-        lfStrikeOut: 0,
-        lfCharSet: 0,
-        lfOutPrecision: OUT_TT_ONLY_PRECIS as u8,
-        lfClipPrecision: 0,
-        lfQuality: 0,
-        lfPitchAndFamily: 0,
-        lfFaceName: [0; LF_FACESIZE],
-    };
-
-    unsafe {
-        let hdc = gdi32::CreateCompatibleDC(ptr::null_mut());
-        gdi32::EnumFontFamiliesExW(hdc,
-                                   &mut config,
-                                   Some(enum_font_callback),
-                                   &mut fonts as *mut Vec<String> as LPARAM,
-                                   0);
-        gdi32::DeleteDC(hdc);
-    }
-
-    for family in fonts {
-        callback(family);
+    let system_fc = FontCollection::system();
+    for family in system_fc.families_iter() {
+        callback(family.name());
     }
 }
 
+// for_each_variation is supposed to return a string that can be
+// atomized and then uniquely used to return back to this font.
+// Some platforms use the full postscript name (MacOS X), or
+// a font filename.
+//
+// For windows we're going to use just a basic integer value that
+// we'll stringify, and then put them all in a HashMap with
+// the actual FontDescriptor there.
+
 pub fn for_each_variation<F>(family_name: &str, mut callback: F) where F: FnMut(String) {
-    callback(family_name.to_owned());
+    let system_fc = FontCollection::system();
+    if let Some(family) = system_fc.get_font_family_by_name(family_name) {
+        let count = family.get_font_count();
+        for i in 0..count {
+            let font = family.get_font(i);
+            let index = FONT_ATOM_COUNTER.fetch_add(1, Ordering::Relaxed);
+            let index_str = format!("{}", index);
+            let atom = Atom::from(index_str.clone());
+
+            {
+                let descriptor = font.to_descriptor();
+                let mut fonts = FONT_ATOM_MAP.lock().unwrap();
+                fonts.insert(atom, descriptor);
+            }
+
+            callback(index_str);
+        }
+    }
+}
+
+pub fn descriptor_from_atom(ident: &Atom) -> FontDescriptor {
+    let fonts = FONT_ATOM_MAP.lock().unwrap();
+    fonts.get(ident).unwrap().clone()
+}
+
+pub fn font_from_atom(ident: &Atom) -> Font {
+    let fonts = FONT_ATOM_MAP.lock().unwrap();
+    FontCollection::system().get_font_from_descriptor(fonts.get(ident).unwrap()).unwrap()
 }

components/gfx/platform/windows/font_template.rs

@@ -2,88 +2,56 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use gdi32;
+use app_units::Au;
 use servo_atoms::Atom;
-use std::ffi::OsString;
-use std::io::Error;
-use std::os::windows::ffi::OsStrExt;
-use std::ptr;
+use serde;
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
+use std::collections::HashMap;
+use std::io;
+use std::ops::Deref;
+use std::sync::Mutex;
 use webrender_traits::NativeFontHandle;
-use winapi::{DWORD, LF_FACESIZE, LOGFONTW, OUT_TT_ONLY_PRECIS, WCHAR};
-
-const GDI_ERROR: DWORD = 0xffffffff;
+use dwrote::{Font};
+use platform::windows::font_list::{descriptor_from_atom, font_from_atom};
 
 #[derive(Deserialize, Serialize, Debug)]
 pub struct FontTemplateData {
-    pub bytes: Vec<u8>,
+    pub bytes: Option<Vec<u8>>,
     pub identifier: Atom,
 }
 
 impl FontTemplateData {
     pub fn new(identifier: Atom,
-               font_data: Option<Vec<u8>>) -> Result<FontTemplateData, Error> {
-        let bytes = match font_data {
-            Some(bytes) => {
-                bytes
-            },
-            None => {
-                assert!(identifier.len() < LF_FACESIZE);
-                let name = OsString::from(identifier.as_ref());
-                let buffer: Vec<WCHAR> = name.encode_wide().collect();
-                let mut string: [WCHAR; LF_FACESIZE] = [0; LF_FACESIZE];
-
-                for (src, dest) in buffer.iter().zip(string.iter_mut()) {
-                    *dest = *src;
-                }
-
-                let config = LOGFONTW {
-                    lfHeight: 0,
-                    lfWidth: 0,
-                    lfEscapement: 0,
-                    lfOrientation: 0,
-                    lfWeight: 0,
-                    lfItalic: 0,
-                    lfUnderline: 0,
-                    lfStrikeOut: 0,
-                    lfCharSet: 0,
-                    lfOutPrecision: OUT_TT_ONLY_PRECIS as u8,
-                    lfClipPrecision: 0,
-                    lfQuality: 0,
-                    lfPitchAndFamily: 0,
-                    lfFaceName: string,
-                };
-
-                unsafe {
-                    let hdc = gdi32::CreateCompatibleDC(ptr::null_mut());
-                    let hfont = gdi32::CreateFontIndirectW(&config as *const _);
-                    gdi32::SelectObject(hdc, hfont as *mut _);
-                    let size = gdi32::GetFontData(hdc, 0, 0, ptr::null_mut(), 0);
-                    assert!(size != GDI_ERROR);
-                    let mut buffer: Vec<u8> = vec![0; size as usize];
-                    let actual_size = gdi32::GetFontData(hdc, 0, 0, buffer.as_mut_ptr() as *mut _, size);
-                    assert!(actual_size == size);
-                    gdi32::DeleteDC(hdc);
-                    gdi32::DeleteObject(hfont as *mut _);
-                    buffer
-                }
-            }
-        };
-
+               font_data: Option<Vec<u8>>) -> Result<FontTemplateData, io::Error> {
         Ok(FontTemplateData {
-            bytes: bytes,
+            bytes: font_data,
             identifier: identifier,
         })
     }
 
     pub fn bytes(&self) -> Vec<u8> {
-        self.bytes.clone()
+        if self.bytes.is_some() {
+            self.bytes.as_ref().unwrap().clone()
+        } else {
+            let font = font_from_atom(&self.identifier);
+            let face = font.create_font_face();
+            let files = face.get_files();
+            assert!(files.len() > 0);
+
+            files[0].get_font_file_bytes()
+        }
     }
 
     pub fn bytes_if_in_memory(&self) -> Option<Vec<u8>> {
-        Some(self.bytes())
+        self.bytes.clone()
     }
 
     pub fn native_font(&self) -> Option<NativeFontHandle> {
-        None
+        if self.bytes.is_some() {
+            panic!("Can't create fonts yet");
+        }
+
+        let descriptor = descriptor_from_atom(&self.identifier);
+        Some(descriptor)
     }
 }