From bc9a0a36a8e21c02a8369b8e5c7cb733ac089acb Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Sat, 17 Sep 2022 10:05:26 -0700
Subject: [PATCH] store requested size alongside deferred font for loading

---
 src/font/DeferredFace.zig | 11 +++++++++++
 src/font/discovery.zig    | 11 ++++++++---
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/src/font/DeferredFace.zig b/src/font/DeferredFace.zig
index 43efbcb72..8a4eb9939 100644
--- a/src/font/DeferredFace.zig
+++ b/src/font/DeferredFace.zig
@@ -23,10 +23,21 @@ fc: if (options.fontconfig) ?Fontconfig else void = if (options.fontconfig) null
 
 /// Fontconfig specific data. This is only present if building with fontconfig.
 pub const Fontconfig = struct {
+    /// The pattern for this font. This must be the "render prepared" pattern.
+    /// (i.e. call FcFontRenderPrepare).
     pattern: *fontconfig.Pattern,
+
+    /// Charset and Langset are used for quick lookup if a codepoint and
+    /// presentation style are supported. They can be derived from pattern
+    /// but are cached since they're frequently used.
     charset: *const fontconfig.CharSet,
     langset: *const fontconfig.LangSet,
 
+    /// The requested size in points for this font. This is used for loading.
+    /// This can't be derived from pattern because the requested size may
+    /// differ from the size the font advertises supported.
+    req_size: u16,
+
     pub fn deinit(self: *Fontconfig) void {
         self.pattern.destroy();
         self.* = undefined;
diff --git a/src/font/discovery.zig b/src/font/discovery.zig
index 06790e01f..dcdb818f6 100644
--- a/src/font/discovery.zig
+++ b/src/font/discovery.zig
@@ -22,8 +22,10 @@ pub const Descriptor = struct {
     /// fontconfig pattern, such as "Fira Code-14:bold".
     family: [:0]const u8,
 
-    /// Font size in points that the font should support.
-    size: u16 = 0,
+    /// Font size in points that the font should support. For conversion
+    /// to pixels, we will use 72 DPI for Mac and 96 DPI for everything else.
+    /// (If pixel conversion is necessary, i.e. emoji fonts)
+    size: u16,
 
     /// True if we want to search specifically for a font that supports
     /// bold, italic, or both.
@@ -81,6 +83,7 @@ pub const Fontconfig = struct {
             .set = res.fs,
             .fonts = res.fs.fonts(),
             .i = 0,
+            .req_size = @floatToInt(u16, (try pat.get(.size, 0)).double),
         };
     }
 
@@ -90,6 +93,7 @@ pub const Fontconfig = struct {
         set: *fontconfig.FontSet,
         fonts: []*fontconfig.Pattern,
         i: usize,
+        req_size: u16,
 
         pub fn deinit(self: *DiscoverIterator) void {
             self.set.destroy();
@@ -117,6 +121,7 @@ pub const Fontconfig = struct {
                     .pattern = font_pattern,
                     .charset = (try font_pattern.get(.charset, 0)).char_set,
                     .langset = (try font_pattern.get(.lang, 0)).lang_set,
+                    .req_size = self.req_size,
                 },
             };
         }
@@ -127,7 +132,7 @@ test {
     const testing = std.testing;
 
     var fc = Fontconfig.init();
-    var it = try fc.discover(.{ .family = "monospace" });
+    var it = try fc.discover(.{ .family = "monospace", .size = 12 });
     defer it.deinit();
     while (try it.next()) |face| {
         try testing.expect(!face.loaded());