Add support for Fontconfig embolden and matrix options

Fixes #1754.

5 files changed, 84 insertions, 14 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7aa65254..633efb0a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,6 +18,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `CopySelection` action which copies into selection buffer on Linux/BSD
 - Option `cursor.thickness` to set terminal cursor thickness
 - Font fallback on Windows
+- Support for Fontconfig embolden and matrix options
 
 ### Changed
 
diff --git a/Cargo.lock b/Cargo.lock
index 1e97707d..97de10d4 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -575,7 +575,7 @@ dependencies = [
  "dwrote 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.20.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "foreign-types 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "freetype-rs 0.24.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "freetype-rs 0.25.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.70 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "servo-fontconfig 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -621,17 +621,17 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "freetype-rs"
-version = "0.24.0"
+version = "0.25.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bitflags 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "freetype-sys 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "freetype-sys 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.70 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "freetype-sys"
-version = "0.11.0"
+version = "0.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cmake 0.1.42 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1638,16 +1638,16 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "libc 0.2.70 (registry+https://github.com/rust-lang/crates.io-index)",
- "servo-fontconfig-sys 5.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "servo-fontconfig-sys 5.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "servo-fontconfig-sys"
-version = "5.0.1"
+version = "5.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "expat-sys 2.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "freetype-sys 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "freetype-sys 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "pkg-config 0.3.17 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -2298,8 +2298,8 @@ dependencies = [
 "checksum foreign-types-macros 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "63f713f8b2aa9e24fec85b0e290c56caee12e3b6ae0aeeda238a75b28251afd6"
 "checksum foreign-types-shared 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "00b0228411908ca8685dba7fc2cdd70ec9990a6e753e89b6ac91a84c40fbaf4b"
 "checksum foreign-types-shared 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7684cf33bb7f28497939e8c7cf17e3e4e3b8d9a0080ffa4f8ae2f515442ee855"
-"checksum freetype-rs 0.24.0 (registry+https://github.com/rust-lang/crates.io-index)" = "340519227cdc8f41c27b3840a02e32dac6102dc314aefe6189cfa355233c445f"
-"checksum freetype-sys 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d48ac0ce366dd47a115ec8e598d7c51b4a974fc52ded5e53a56b31f55f34f3ea"
+"checksum freetype-rs 0.25.0 (registry+https://github.com/rust-lang/crates.io-index)" = "5e687cf953d7052be94742baf3fc63b1ea21ada7d9b45f7b1918221accebf1ae"
+"checksum freetype-sys 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7530337a8e76db5271f1b5f81dd5340b0adaea235cb089cefa1928bd0cb9ee71"
 "checksum fsevent 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "5ab7d1bd1bd33cc98b0889831b72da23c0aa4df9cec7e0702f46ecea04b35db6"
 "checksum fsevent-sys 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "f41b048a94555da0f42f1d632e2e19510084fb8e303b0daa2816e733fb3644a0"
 "checksum fuchsia-zircon 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "2e9763c69ebaae630ba35f74888db465e49e259ba1bc0eda7d06f4a067615d82"
@@ -2417,7 +2417,7 @@ dependencies = [
 "checksum serde_json 1.0.53 (registry+https://github.com/rust-lang/crates.io-index)" = "993948e75b189211a9b31a7528f950c6adc21f9720b6438ff80a7fa2f864cea2"
 "checksum serde_yaml 0.8.12 (registry+https://github.com/rust-lang/crates.io-index)" = "16c7a592a1ec97c9c1c68d75b6e537dcbf60c7618e038e7841e00af1d9ccf0c4"
 "checksum servo-fontconfig 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0b47fef69c52fb55838c756949c60595f0b855daa4e82fc52ad99ff3e03e2c70"
-"checksum servo-fontconfig-sys 5.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "1c5e8d42c2957f6f433d90ab61277ed0226b3f49fffb19aa5493213c42e5d6df"
+"checksum servo-fontconfig-sys 5.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "facb23c6a801c935c3bddfdd7dc4e823af853babc5b0c90ffa3419ebef5d92c7"
 "checksum shared_library 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)" = "5a9e7e0f2bfae24d8a5b5a66c5b257a83c7412304311512a0c054cd5e619da11"
 "checksum shlex 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7fdf1b9db47230893d76faad238fd6097fd6d6a9245cd7a4d90dbd639536bbd2"
 "checksum signal-hook 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)" = "8ff2db2112d6c761e12522c65f7768548bd6e8cd23d2a9dae162520626629bd6"
diff --git a/font/Cargo.toml b/font/Cargo.toml
index 866b14cf..d847a2f7 100644
--- a/font/Cargo.toml
+++ b/font/Cargo.toml
@@ -14,7 +14,7 @@ log = "0.4"
 
 [target.'cfg(not(any(target_os = "macos", windows)))'.dependencies]
 servo-fontconfig = "0.5.0"
-freetype-rs = "0.24"
+freetype-rs = "0.25"
 
 [target.'cfg(target_os = "macos")'.dependencies]
 core-foundation = "0.6"
diff --git a/font/src/ft/fc/pattern.rs b/font/src/ft/fc/pattern.rs
index f40cc9c9..da459b6d 100644
--- a/font/src/ft/fc/pattern.rs
+++ b/font/src/ft/fc/pattern.rs
@@ -21,10 +21,14 @@ use std::str;
 use foreign_types::{foreign_type, ForeignType, ForeignTypeRef};
 use libc::{c_char, c_double, c_int};
 
+use super::ffi::FcMatrix;
 use super::ffi::FcResultMatch;
 use super::ffi::{FcBool, FcFontRenderPrepare, FcPatternGetBool, FcPatternGetDouble};
 use super::ffi::{FcChar8, FcConfigSubstitute, FcDefaultSubstitute, FcPattern, FcPatternHash};
-use super::ffi::{FcPatternAddCharSet, FcPatternDestroy, FcPatternDuplicate, FcPatternGetCharSet};
+use super::ffi::{
+    FcPatternAddCharSet, FcPatternDestroy, FcPatternDuplicate, FcPatternGetCharSet,
+    FcPatternGetMatrix,
+};
 use super::ffi::{FcPatternAddDouble, FcPatternAddString, FcPatternCreate, FcPatternGetString};
 use super::ffi::{FcPatternAddInteger, FcPatternGetInteger, FcPatternPrint};
 
@@ -572,9 +576,10 @@ impl PatternRef {
         }
     }
 
+    /// Get charset from the pattern.
     pub fn get_charset(&self) -> Option<&CharSetRef> {
         unsafe {
-            let mut charset: *mut _ = ptr::null_mut();
+            let mut charset = ptr::null_mut();
 
             let result = FcPatternGetCharSet(
                 self.as_ptr(),
@@ -591,6 +596,25 @@ impl PatternRef {
         }
     }
 
+    /// Get matrix from the pattern.
+    pub fn get_matrix(&self) -> Option<FcMatrix> {
+        unsafe {
+            let mut matrix = ptr::null_mut();
+            let result = FcPatternGetMatrix(
+                self.as_ptr(),
+                b"matrix\0".as_ptr() as *mut c_char,
+                0,
+                &mut matrix,
+            );
+
+            if result == FcResultMatch {
+                Some(*matrix)
+            } else {
+                None
+            }
+        }
+    }
+
     pub fn file(&self, index: usize) -> Option<PathBuf> {
         unsafe { self.get_string(b"file\0").nth(index) }.map(From::from)
     }
diff --git a/font/src/ft/mod.rs b/font/src/ft/mod.rs
index ef1afb5f..33cd2263 100644
--- a/font/src/ft/mod.rs
+++ b/font/src/ft/mod.rs
@@ -19,7 +19,7 @@ use std::fmt::{self, Display, Formatter};
 use std::rc::Rc;
 
 use freetype::tt_os2::TrueTypeOS2Table;
-use freetype::{self, Library};
+use freetype::{self, Library, Matrix};
 use freetype::{freetype_sys, Face as FTFace};
 use libc::c_uint;
 use log::{debug, trace};
@@ -63,6 +63,8 @@ struct FaceLoadingProperties {
     lcd_filter: c_uint,
     non_scalable: Option<f32>,
     colored: bool,
+    embolden: bool,
+    matrix: Option<Matrix>,
     pixelsize_fixup_factor: Option<f64>,
     ft_face: Rc<FTFace>,
 }
@@ -99,6 +101,11 @@ fn to_freetype_26_6(f: f32) -> isize {
     ((1i32 << 6) as f32 * f) as isize
 }
 
+#[inline]
+fn to_fixedpoint_16_6(f: f64) -> i64 {
+    (f * 65536.0) as i64
+}
+
 impl Rasterize for FreeTypeRasterizer {
     type Err = Error;
 
@@ -333,6 +340,18 @@ impl FreeTypeRasterizer {
                 Some(pattern.pixelsize().next().expect("has 1+ pixelsize") as f32)
             };
 
+            let embolden = pattern.embolden().next().unwrap_or(false);
+
+            let matrix = pattern.get_matrix().map(|matrix| {
+                // Convert Fontconfig matrix to FreeType matrix.
+                let xx = to_fixedpoint_16_6(matrix.xx);
+                let xy = to_fixedpoint_16_6(matrix.xy);
+                let yx = to_fixedpoint_16_6(matrix.yx);
+                let yy = to_fixedpoint_16_6(matrix.yy);
+
+                Matrix { xx, xy, yx, yy }
+            });
+
             let pixelsize_fixup_factor = pattern.pixelsizefixupfactor().next();
 
             let face = FaceLoadingProperties {
@@ -341,6 +360,8 @@ impl FreeTypeRasterizer {
                 lcd_filter: Self::ft_lcd_filter(pattern),
                 non_scalable,
                 colored: ft_face.has_color(),
+                embolden,
+                matrix,
                 pixelsize_fixup_factor,
                 ft_face,
             };
@@ -425,6 +446,30 @@ impl FreeTypeRasterizer {
         face.ft_face.load_glyph(index as u32, face.load_flags)?;
 
         let glyph = face.ft_face.glyph();
+
+        // Generate synthetic bold.
+        if face.embolden {
+            unsafe {
+                freetype_sys::FT_GlyphSlot_Embolden(glyph.raw()
+                    as *const freetype_sys::FT_GlyphSlotRec
+                    as *mut freetype_sys::FT_GlyphSlotRec);
+            }
+        }
+
+        // Transform glyphs with the matrix from Fontconfig. Primarily used to generate italics.
+        if let Some(matrix) = face.matrix.as_ref() {
+            let glyph = face.ft_face.raw().glyph;
+
+            unsafe {
+                // Check that the glyph is a vectorial outline, not a bitmap.
+                if (*glyph).format == freetype_sys::FT_GLYPH_FORMAT_OUTLINE {
+                    let outline = &(*glyph).outline;
+
+                    freetype_sys::FT_Outline_Transform(outline, matrix);
+                }
+            }
+        }
+
         glyph.render_glyph(face.render_mode)?;
 
         let (pixel_height, pixel_width, buf) = Self::normalize_buffer(&glyph.bitmap())?;