Add SVG favicon.

book-example/src/format/theme/README.md

@@ -22,7 +22,8 @@ Here are the files you can override:
 - **_highlight.js_** is the JavaScript that is used to highlight code snippets,
   you should not need to modify this.
 - **_highlight.css_** is the theme used for the code highlighting.
-- **_favicon.png_** the favicon that will be used.
+- **_favicon.svg_** and **_favicon.png_** the favicon that will be used. The SVG
+  version is used by [newer browsers].
 
 Generally, when you want to tweak the theme, you don't need to override all the
 files. If you only need changes in the stylesheet, there is no point in
@@ -40,3 +41,4 @@ If you completely replace all built-in themes, be sure to also set
 built-in `navy` theme.
 
 [`output.html.preferred-dark-theme`]: ../config.md#html-renderer-options
+[newer browsers]: https://caniuse.com/#feat=link-icon-svg

src/book/init.rs

@@ -143,7 +143,10 @@ impl BookBuilder {
         variables_css.write_all(theme::VARIABLES_CSS)?;
 
         let mut favicon = File::create(themedir.join("favicon.png"))?;
-        favicon.write_all(theme::FAVICON)?;
+        favicon.write_all(theme::FAVICON_PNG)?;
+
+        let mut favicon = File::create(themedir.join("favicon.svg"))?;
+        favicon.write_all(theme::FAVICON_SVG)?;
 
         let mut js = File::create(themedir.join("book.js"))?;
         js.write_all(theme::JS)?;

src/renderer/html_handlebars/hbs_renderer.rs

@@ -192,7 +192,8 @@ impl HtmlHandlebars {
         write_file(destination, "css/chrome.css", &theme.chrome_css)?;
         write_file(destination, "css/print.css", &theme.print_css)?;
         write_file(destination, "css/variables.css", &theme.variables_css)?;
-        write_file(destination, "favicon.png", &theme.favicon)?;
+        write_file(destination, "favicon.png", &theme.favicon_png)?;
+        write_file(destination, "favicon.svg", &theme.favicon_svg)?;
         write_file(destination, "highlight.css", &theme.highlight_css)?;
         write_file(destination, "tomorrow-night.css", &theme.tomorrow_night_css)?;
         write_file(destination, "ayu-highlight.css", &theme.ayu_highlight_css)?;
@@ -562,7 +563,6 @@ fn make_data(
         "description".to_owned(),
         json!(config.book.description.clone().unwrap_or_default()),
     );
-    data.insert("favicon".to_owned(), json!("favicon.png"));
     if let Some(ref livereload) = html_config.livereload_url {
         data.insert("livereload".to_owned(), json!(livereload));
     }

src/theme/index.hbs

@@ -20,7 +20,8 @@
         <meta name="viewport" content="width=device-width, initial-scale=1">
         <meta name="theme-color" content="#ffffff" />
 
-        <link rel="shortcut icon" href="{{ path_to_root }}{{ favicon }}">
+        <link rel="icon" href="{{ path_to_root }}favicon.svg">
+        <link rel="shortcut icon" href="{{ path_to_root }}favicon.png">
         <link rel="stylesheet" href="{{ path_to_root }}css/variables.css">
         <link rel="stylesheet" href="{{ path_to_root }}css/general.css">
         <link rel="stylesheet" href="{{ path_to_root }}css/chrome.css">

src/theme/mod.rs

@@ -21,7 +21,8 @@ pub static CHROME_CSS: &[u8] = include_bytes!("css/chrome.css");
 pub static GENERAL_CSS: &[u8] = include_bytes!("css/general.css");
 pub static PRINT_CSS: &[u8] = include_bytes!("css/print.css");
 pub static VARIABLES_CSS: &[u8] = include_bytes!("css/variables.css");
-pub static FAVICON: &[u8] = include_bytes!("favicon.png");
+pub static FAVICON_PNG: &[u8] = include_bytes!("favicon.png");
+pub static FAVICON_SVG: &[u8] = include_bytes!("favicon.svg");
 pub static JS: &[u8] = include_bytes!("book.js");
 pub static HIGHLIGHT_JS: &[u8] = include_bytes!("highlight.js");
 pub static TOMORROW_NIGHT_CSS: &[u8] = include_bytes!("tomorrow-night.css");
@@ -53,7 +54,8 @@ pub struct Theme {
     pub general_css: Vec<u8>,
     pub print_css: Vec<u8>,
     pub variables_css: Vec<u8>,
-    pub favicon: Vec<u8>,
+    pub favicon_png: Vec<u8>,
+    pub favicon_svg: Vec<u8>,
     pub js: Vec<u8>,
     pub highlight_css: Vec<u8>,
     pub tomorrow_night_css: Vec<u8>,
@@ -89,7 +91,8 @@ impl Theme {
                     theme_dir.join("css/variables.css"),
                     &mut theme.variables_css,
                 ),
-                (theme_dir.join("favicon.png"), &mut theme.favicon),
+                (theme_dir.join("favicon.png"), &mut theme.favicon_png),
+                (theme_dir.join("favicon.svg"), &mut theme.favicon_svg),
                 (theme_dir.join("highlight.js"), &mut theme.highlight_js),
                 (theme_dir.join("clipboard.min.js"), &mut theme.clipboard_js),
                 (theme_dir.join("highlight.css"), &mut theme.highlight_css),
@@ -129,7 +132,8 @@ impl Default for Theme {
             general_css: GENERAL_CSS.to_owned(),
             print_css: PRINT_CSS.to_owned(),
             variables_css: VARIABLES_CSS.to_owned(),
-            favicon: FAVICON.to_owned(),
+            favicon_png: FAVICON_PNG.to_owned(),
+            favicon_svg: FAVICON_SVG.to_owned(),
             js: JS.to_owned(),
             highlight_css: HIGHLIGHT_CSS.to_owned(),
             tomorrow_night_css: TOMORROW_NIGHT_CSS.to_owned(),
@@ -182,6 +186,7 @@ mod tests {
             "redirect.hbs",
             "header.hbs",
             "favicon.png",
+            "favicon.svg",
             "css/chrome.css",
             "css/fonts.css",
             "css/general.css",
@@ -214,7 +219,8 @@ mod tests {
             general_css: Vec::new(),
             print_css: Vec::new(),
             variables_css: Vec::new(),
-            favicon: Vec::new(),
+            favicon_png: Vec::new(),
+            favicon_svg: Vec::new(),
             js: Vec::new(),
             highlight_css: Vec::new(),
             tomorrow_night_css: Vec::new(),