font/core-text: discovery supports style search

src/cli/list_fonts.zig

@@ -14,6 +14,9 @@ pub const Config = struct {
     /// matching this family will be listed.
     family: ?[:0]const u8 = null,
 
+    /// The style name to search for.
+    style: ?[:0]const u8 = null,
+
     /// Font styles to search for. If this is set, then only fonts that
     /// match the given styles will be listed.
     bold: bool = false,
@@ -84,6 +87,7 @@ fn runArgs(alloc_gpa: Allocator, argsIter: anytype) !u8 {
     defer disco.deinit();
     var disco_it = try disco.discover(.{
         .family = config.family,
+        .style = config.style,
         .bold = config.bold,
         .italic = config.italic,
     });

src/font/discovery.zig

@@ -31,6 +31,12 @@ pub const Descriptor = struct {
     /// fontconfig pattern, such as "Fira Code-14:bold".
     family: ?[:0]const u8 = null,
 
+    /// Specific font style to search for. This will filter the style
+    /// string the font advertises. The "bold/italic" booleans later in this
+    /// struct filter by the style trait the font has, not the string, so
+    /// these can be used in conjunction or not.
+    style: ?[:0]const u8 = null,
+
     /// A codepoint that this font must be able to render.
     codepoint: u32 = 0,
 
@@ -99,6 +105,16 @@ pub const Descriptor = struct {
             );
         }
 
+        // Style
+        if (self.style) |style_bytes| {
+            const style = try macos.foundation.String.createWithBytes(style_bytes, .utf8, false);
+            defer style.release();
+            attrs.setValue(
+                macos.text.FontAttribute.style_name.key(),
+                style,
+            );
+        }
+
         // Codepoint support
         if (self.codepoint > 0) {
             const cs = try macos.foundation.CharacterSet.createWithCharactersInRange(.{