font/coretext: ability to set variation axes

pkg/macos/text/font.zig

@@ -39,6 +39,14 @@ pub const Font = opaque {
         c.CFRelease(self);
     }
 
+    pub fn retain(self: *Font) void {
+        _ = c.CFRetain(self);
+    }
+
+    pub fn copyDescriptor(self: *Font) *text.FontDescriptor {
+        return @ptrCast(@constCast(c.CTFontCopyFontDescriptor(@ptrCast(self))));
+    }
+
     pub fn getGlyphsForCharacters(self: *Font, chars: []const u16, glyphs: []graphics.Glyph) bool {
         assert(chars.len == glyphs.len);
         return c.CTFontGetGlyphsForCharacters(

pkg/macos/text/font_descriptor.zig

@@ -31,6 +31,21 @@ pub const FontDescriptor = opaque {
         ) orelse Allocator.Error.OutOfMemory;
     }
 
+    pub fn createCopyWithVariation(
+        original: *FontDescriptor,
+        id: *foundation.Number,
+        value: f64,
+    ) Allocator.Error!*FontDescriptor {
+        return @as(
+            ?*FontDescriptor,
+            @ptrCast(@constCast(c.CTFontDescriptorCreateCopyWithVariation(
+                @ptrCast(original),
+                @ptrCast(id),
+                value,
+            ))),
+        ) orelse Allocator.Error.OutOfMemory;
+    }
+
     pub fn release(self: *FontDescriptor) void {
         c.CFRelease(self);
     }