From f2f644d3de8dee9a71c90e0376fd44531e5c2eec Mon Sep 17 00:00:00 2001
From: Cristian Brinza <cristianb@gmail.com>
Date: Sat, 17 Aug 2024 15:49:06 +0300
Subject: [PATCH] Add glyph pair kerning bindings (#55)

* Add kerning pair bindings

Signed-off-by: crbrz <cristianb@gmail.com>

* Use cached IDWriteFontFace1

Signed-off-by: crbrz <cristianb@gmail.com>

* Fixed build warnings

Signed-off-by: crbrz <cristianb@gmail.com>

---------

Signed-off-by: crbrz <cristianb@gmail.com>
---
 src/com_helpers.rs           |  2 +-
 src/font_face.rs             | 53 +++++++++++++++++++++++++++++++++---
 src/font_file_loader_impl.rs |  2 +-
 src/helpers.rs               |  6 +---
 4 files changed, 52 insertions(+), 11 deletions(-)

diff --git a/src/com_helpers.rs b/src/com_helpers.rs
index b4bcf16..aa28b2d 100644
--- a/src/com_helpers.rs
+++ b/src/com_helpers.rs
@@ -122,6 +122,6 @@ where
     }
 
     unsafe fn destroy(thing: *mut Interface) {
-        Box::from_raw(thing as *mut ComRepr<Self, Self::Vtbl>);
+        let _ = Box::from_raw(thing as *mut ComRepr<Self, Self::Vtbl>);
     }
 }
diff --git a/src/font_face.rs b/src/font_face.rs
index be0091e..2e3d149 100644
--- a/src/font_face.rs
+++ b/src/font_face.rs
@@ -21,6 +21,7 @@ use winapi::um::dwrite::{DWRITE_GLYPH_OFFSET, DWRITE_MATRIX, DWRITE_RENDERING_MO
 use winapi::um::dwrite::{DWRITE_RENDERING_MODE_DEFAULT, DWRITE_RENDERING_MODE_NATURAL_SYMMETRIC};
 use winapi::um::dwrite_1::IDWriteFontFace1;
 use winapi::um::dwrite_3::{IDWriteFontFace5, IDWriteFontResource, DWRITE_FONT_AXIS_VALUE};
+use winapi::Interface;
 use wio::com::ComPtr;
 
 use super::{DWriteFactory, DefaultDWriteRenderParams, FontFile, FontMetrics};
@@ -30,6 +31,7 @@ use crate::outline_builder::OutlineBuilder;
 
 pub struct FontFace {
     native: UnsafeCell<ComPtr<IDWriteFontFace>>,
+    face1: UnsafeCell<Option<ComPtr<IDWriteFontFace1>>>,
     face5: UnsafeCell<Option<ComPtr<IDWriteFontFace5>>>,
 }
 
@@ -38,6 +40,7 @@ impl FontFace {
         let cell = UnsafeCell::new(native);
         FontFace {
             native: cell,
+            face1: UnsafeCell::new(None),
             face5: UnsafeCell::new(None),
         }
     }
@@ -99,7 +102,7 @@ impl FontFace {
 
     pub fn metrics(&self) -> FontMetrics {
         unsafe {
-            let font_1: Option<ComPtr<IDWriteFontFace1>> = (*self.native.get()).cast().ok();
+            let font_1 = self.get_face1();
             match font_1 {
                 None => {
                     let mut metrics = mem::zeroed();
@@ -286,6 +289,34 @@ impl FontFace {
         }
     }
 
+    pub fn has_kerning_pairs(&self) -> bool {
+        unsafe {
+            match self.get_face1() {
+                Some(face1) => face1.HasKerningPairs() == TRUE,
+                None => false,
+            }
+        }
+    }
+
+    pub fn get_glyph_pair_kerning_adjustment(&self, first_glyph: u16, second_glyph: u16) -> i32 {
+        unsafe {
+            match self.get_face1() {
+                Some(face1) => {
+                    let mut adjustments = [0; 2];
+                    let hr = face1.GetKerningPairAdjustments(
+                        2,
+                        [first_glyph, second_glyph].as_ptr(),
+                        adjustments.as_mut_ptr(),
+                    );
+                    assert_eq!(hr, S_OK);
+
+                    adjustments[0]
+                }
+                None => 0,
+            }
+        }
+    }
+
     #[inline]
     pub fn get_type(&self) -> FontFaceType {
         unsafe {
@@ -307,12 +338,25 @@ impl FontFace {
         unsafe { (*self.native.get()).GetIndex() }
     }
 
+    #[inline]
+    unsafe fn get_face1(&self) -> Option<ComPtr<IDWriteFontFace1>> {
+        self.get_interface(&self.face1)
+    }
+
     #[inline]
     unsafe fn get_face5(&self) -> Option<ComPtr<IDWriteFontFace5>> {
-        if (*self.face5.get()).is_none() {
-            *self.face5.get() = (*self.native.get()).cast().ok()
+        self.get_interface(&self.face5)
+    }
+
+    #[inline]
+    unsafe fn get_interface<I: Interface>(
+        &self,
+        interface: &UnsafeCell<Option<ComPtr<I>>>,
+    ) -> Option<ComPtr<I>> {
+        if (*interface.get()).is_none() {
+            *interface.get() = (*self.native.get()).cast().ok()
         }
-        (*self.face5.get()).clone()
+        (*interface.get()).clone()
     }
 
     pub fn has_variations(&self) -> bool {
@@ -358,6 +402,7 @@ impl Clone for FontFace {
         unsafe {
             FontFace {
                 native: UnsafeCell::new((*self.native.get()).clone()),
+                face1: UnsafeCell::new(None),
                 face5: UnsafeCell::new(None),
             }
         }
diff --git a/src/font_file_loader_impl.rs b/src/font_file_loader_impl.rs
index 30230d0..6a3f22d 100644
--- a/src/font_file_loader_impl.rs
+++ b/src/font_file_loader_impl.rs
@@ -178,7 +178,7 @@ unsafe impl Sync for FontFileLoaderWrapper {}
 
 lazy_static! {
     static ref FONT_FILE_STREAM_MAP: Mutex<HashMap<usize, FontFileStreamPtr>> =
-        { Mutex::new(HashMap::new()) };
+        Mutex::new(HashMap::new());
     static ref FONT_FILE_LOADER: Mutex<FontFileLoaderWrapper> = {
         unsafe {
             let ffl_native = FontFileLoader::new();
diff --git a/src/helpers.rs b/src/helpers.rs
index 804ff9e..45bf005 100644
--- a/src/helpers.rs
+++ b/src/helpers.rs
@@ -19,7 +19,7 @@ lazy_static! {
             locale
         }
     };
-    static ref EN_US_LOCALE: Vec<wchar_t> = { OsStr::new("en-us").to_wide_null() };
+    static ref EN_US_LOCALE: Vec<wchar_t> = OsStr::new("en-us").to_wide_null();
 }
 
 pub fn get_locale_string(strings: &mut ComPtr<IDWriteLocalizedStrings>) -> String {
@@ -51,7 +51,6 @@ pub fn get_locale_string(strings: &mut ComPtr<IDWriteLocalizedStrings>) -> Strin
 // ToWide from https://github.com/retep998/wio-rs/blob/master/src/wide.rs
 
 pub trait ToWide {
-    fn to_wide(&self) -> Vec<u16>;
     fn to_wide_null(&self) -> Vec<u16>;
 }
 
@@ -59,9 +58,6 @@ impl<T> ToWide for T
 where
     T: AsRef<OsStr>,
 {
-    fn to_wide(&self) -> Vec<u16> {
-        self.as_ref().encode_wide().collect()
-    }
     fn to_wide_null(&self) -> Vec<u16> {
         self.as_ref().encode_wide().chain(Some(0)).collect()
     }