From f71e1a0bb12a3b8ca37f357fc8488bee9cba8f4c Mon Sep 17 00:00:00 2001
From: Aloxaf <Aloxafx@gmail.com>
Date: Fri, 14 Oct 2022 14:49:24 +0800
Subject: [PATCH] fix: font fallback for harfbuzz

close #191
---
 Cargo.lock  |  2 +-
 Cargo.toml  |  2 +-
 README.md   | 13 +++++--------
 src/font.rs | 38 ++++++++++++++++++++++++++------------
 4 files changed, 33 insertions(+), 22 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 6bf95f3..1902b84 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1273,7 +1273,7 @@ checksum = "24188a676b6ae68c3b2cb3a01be17fbf7240ce009799bb56d5b1409051e78fde"
 
 [[package]]
 name = "silicon"
-version = "0.5.0"
+version = "0.5.1"
 dependencies = [
  "anyhow",
  "clipboard",
diff --git a/Cargo.toml b/Cargo.toml
index 92cfd79..51a98d0 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "silicon"
-version = "0.5.0"
+version = "0.5.1"
 description = "Create beautiful image of your code"
 authors = ["Aloxaf <aloxafx@gmail.com>"]
 categories = ["command-line-utilities"]
diff --git a/README.md b/README.md
index 6472020..87cae0e 100644
--- a/README.md
+++ b/README.md
@@ -38,13 +38,10 @@ cargo install silicon
 
 ### AUR
 
-Silicon is available on AUR (Thanks to @radmen).
+Silicon is available in the official repository:
 
-You can install it with any AUR helpers you like.
-
-eg.
 ```bash
-pikaur -S silicon
+pacman -S silicon
 ```
 
 ### Homebrew
@@ -61,18 +58,18 @@ brew install silicon
 ```bash
 sudo apt install expat
 sudo apt install libxml2-dev
-sudo apt install pkg-config libasound2-dev libssl-dev cmake libfreetype6-dev libexpat1-dev libxcb-composite0-dev
+sudo apt install pkg-config libasound2-dev libssl-dev cmake libfreetype6-dev libexpat1-dev libxcb-composite0-dev libharfbuzz-dev
 ```
 
 ### Fedora
 ```bash
-sudo dnf install cmake expat-devel libxcb-devel freetype-devel libxml2-devel
+sudo dnf install cmake expat-devel libxcb-devel freetype-devel libxml2-devel harfbuzz
 ```
 
 ### Arch Linux
 
 ```bash
-sudo pacman -S --needed pkgconf freetype2 fontconfig libxcb xclip
+sudo pacman -S --needed pkgconf freetype2 fontconfig libxcb xclip harfbuzz
 ```
 
 ## Examples
diff --git a/src/font.rs b/src/font.rs
index 89cd9c3..f08854c 100644
--- a/src/font.rs
+++ b/src/font.rs
@@ -28,6 +28,7 @@ use pathfinder_geometry::transform2d::Transform2F;
 use std::collections::HashMap;
 use std::sync::Arc;
 use syntect::highlighting;
+use log::trace;
 
 /// Font style
 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
@@ -194,7 +195,6 @@ impl FontCollection {
         Ok(Self(fonts))
     }
 
-    #[cfg(target_os = "windows")]
     fn glyph_for_char(&self, c: char, style: FontStyle) -> Option<(u32, &ImageFont, &Font)> {
         for font in &self.0 {
             let result = font.get_by_style(style);
@@ -235,20 +235,34 @@ impl FontCollection {
         Ok(glyph_ids)
     }
 
+    #[cfg(not(target_os = "windows"))]
+    fn split_by_font(&self, text: &str, style: FontStyle) -> Vec<(&ImageFont, &Font, String)> {
+        let mut result: Vec<(&ImageFont, &Font, String)> = vec![];
+        for c in text.chars() {
+            if let Some((_, imfont, font)) = self.glyph_for_char(c, style) {
+                if result.is_empty() || !std::ptr::eq(result.last().unwrap().0, imfont) {
+                    result.push((imfont, font, String::new()));
+                }
+                if std::ptr::eq(result.last().unwrap().0, imfont) {
+                    result.last_mut().unwrap().2.push(c);
+                }
+            }
+        }
+        trace!("{:#?}", &result);
+        result
+    }
+
     #[cfg(not(target_os = "windows"))]
     fn layout(&self, text: &str, style: FontStyle) -> (Vec<PositionedGlyph>, u32) {
         let mut delta_x = 0;
         let height = self.get_font_height();
 
-        let imfont = self.0.get(0).unwrap();
-        let font = imfont.get_by_style(style);
-        let mut hb_font = HBFont::new(font);
-        // apply font features especially ligature with a shape engine
-        let shaped_glyphs = self.shape_text(&mut hb_font, text).unwrap();
-
-        let glyphs = shaped_glyphs
-            .iter()
-            .map(|id| {
+        let mut glyphs = Vec::with_capacity(text.len());
+        for (imfont, font, text) in self.split_by_font(text, style) {
+            let mut hb_font = HBFont::new(font);
+            // apply font features especially ligature with a shape engine
+            let shaped_glyphs = self.shape_text(&mut hb_font, &text).unwrap();
+            glyphs.extend(shaped_glyphs.iter().map(|id| {
                 let raster_rect = font
                     .raster_bounds(
                         *id,
@@ -268,8 +282,8 @@ impl FontCollection {
                     raster_rect,
                     position,
                 }
-            })
-            .collect();
+            }))
+        }
 
         (glyphs, delta_x)
     }