font: add scale groups to nerd font constraints

We do this by characterizing the shared bounding boxes in a static copy
of the symbols only nerd font when we're doing the codegen. This allows
us to get results of our scaling that are just as good as in a patched
font, since related glyphs can now be sized and positioned relative to
each other.

src/font/face.zig

@@ -144,6 +144,23 @@ pub const RenderOptions = struct {
         /// Bottom padding when resizing.
         pad_bottom: f64 = 0.0,
 
+        // This acts as a multiple of the provided width when applying
+        // constraints, so if this is 1.6 for example, then a width of
+        // 10 would be treated as though it were 16.
+        group_width: f64 = 1.0,
+        // This acts as a multiple of the provided height when applying
+        // constraints, so if this is 1.6 for example, then a height of
+        // 10 would be treated as though it were 16.
+        group_height: f64 = 1.0,
+        // This is an x offset for the actual width within the group width.
+        // If this is 0.5 then the glyph will be offset so that its left
+        // edge sits at the halfway point of the group width.
+        group_x: f64 = 0.0,
+        // This is a y offset for the actual height within the group height.
+        // If this is 0.5 then the glyph will be offset so that its bottom
+        // edge sits at the halfway point of the group height.
+        group_y: f64 = 0.0,
+
         /// Maximum ratio of width to height when resizing.
         max_xy_ratio: ?f64 = null,
 
@@ -245,6 +262,10 @@ pub const RenderOptions = struct {
             g.x -= self.pad_left * available_width;
             g.y -= self.pad_bottom * available_height;
 
+            // Multiply by group width and height for better sizing.
+            g.width *= self.group_width;
+            g.height *= self.group_height;
+
             switch (self.size_horizontal) {
                 .none => {},
                 .fit => if (g.width > w) {
@@ -323,6 +344,14 @@ pub const RenderOptions = struct {
                 },
             }
 
+            // Add group-relative position
+            g.x += self.group_x * g.width;
+            g.y += self.group_y * g.height;
+
+            // Divide group width and height back out before we align.
+            g.width /= self.group_width;
+            g.height /= self.group_height;
+
             if (self.max_xy_ratio) |ratio| if (g.width > g.height * ratio) {
                 const orig_width = g.width;
                 g.width = g.height * ratio;

src/font/nerd_font_attributes.zig

@@ -34,7 +34,35 @@ pub fn getConstraint(cp: u21) Constraint {
             .pad_top = 0.1,
             .pad_bottom = 0.1,
         },
-        0x276c...0x2771,
+        0x276c...0x276d,
+        => .{
+            .size_horizontal = .cover,
+            .size_vertical = .fit,
+            .max_constraint_width = 1,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.4028056112224450,
+            .group_height = 1.1222570532915361,
+            .group_x = 0.1428571428571428,
+            .group_y = 0.0349162011173184,
+            .pad_top = 0.15,
+            .pad_bottom = 0.15,
+        },
+        0x276e...0x276f,
+        => .{
+            .size_horizontal = .cover,
+            .size_vertical = .fit,
+            .max_constraint_width = 1,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0115606936416186,
+            .group_height = 1.1222570532915361,
+            .group_x = 0.0057142857142857,
+            .group_y = 0.0125698324022346,
+            .pad_top = 0.15,
+            .pad_bottom = 0.15,
+        },
+        0x2770...0x2771,
         => .{
             .size_horizontal = .cover,
             .size_vertical = .fit,
@@ -357,8 +385,46 @@ pub fn getConstraint(cp: u21) Constraint {
         0x2b58,
         0xe000...0xe0a9,
         0xe4fa...0xe7ef,
-        0xea60...0xec1e,
+        0xea60,
-        0xed00...0xf847,
+        0xea62...0xea7c,
+        0xea7e...0xea98,
+        0xeaa3...0xeab3,
+        0xeab8...0xead3,
+        0xead7...0xeb42,
+        0xeb44...0xeb6d,
+        0xeb72...0xeb89,
+        0xeb8b...0xeb99,
+        0xeb9b...0xebd4,
+        0xebd6,
+        0xebd8...0xec06,
+        0xec08...0xec0a,
+        0xec0d...0xec1e,
+        0xed00...0xf018,
+        0xf01a...0xf02f,
+        0xf031...0xf03c,
+        0xf041...0xf043,
+        0xf045...0xf049,
+        0xf04b...0xf050,
+        0xf054...0xf059,
+        0xf05c...0xf070,
+        0xf072...0xf077,
+        0xf079...0xf07a,
+        0xf07c...0xf080,
+        0xf082...0xf08b,
+        0xf08d...0xf091,
+        0xf093...0xf09b,
+        0xf09d...0xf09e,
+        0xf0a0,
+        0xf0a5...0xf0a9,
+        0xf0ab...0xf0c9,
+        0xf0cb...0xf0d5,
+        0xf0d7...0xf0dd,
+        0xf0df...0xf0e6,
+        0xf0e8...0xf295,
+        0xf297...0xf2c1,
+        0xf2c6...0xf2ef,
+        0xf2f1...0xf305,
+        0xf307...0xf847,
         0xf0001...0xf1af0,
         => .{
             .size_horizontal = .fit,
@@ -367,6 +433,641 @@ pub fn getConstraint(cp: u21) Constraint {
             .align_horizontal = .center,
             .align_vertical = .center,
         },
+        0xea61,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.3315669947009841,
+            .group_height = 1.0763840224246670,
+            .group_x = 0.0847072200113701,
+            .group_y = 0.0709635416666667,
+        },
+        0xea7d,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.1913145539906103,
+            .group_height = 1.1428571428571428,
+            .group_x = 0.0916256157635468,
+            .group_y = 0.0415039062500000,
+        },
+        0xea99,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0639412997903563,
+            .group_height = 2.0940695296523519,
+            .group_x = 0.0295566502463054,
+            .group_y = 0.2270507812500000,
+        },
+        0xea9a,
+        0xeaa1,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.3029525032092426,
+            .group_height = 1.1729667812142039,
+            .group_x = 0.1527093596059113,
+            .group_y = 0.0751953125000000,
+        },
+        0xea9b,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.1639908256880733,
+            .group_height = 1.3128205128205128,
+            .group_x = 0.0719211822660099,
+            .group_y = 0.0869140625000000,
+        },
+        0xea9c,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.1639908256880733,
+            .group_height = 1.3195876288659794,
+            .group_x = 0.0719211822660099,
+            .group_y = 0.0830078125000000,
+        },
+        0xea9d,
+        0xeaa0,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 2.4457831325301207,
+            .group_height = 1.9692307692307693,
+            .group_x = 0.2857142857142857,
+            .group_y = 0.2763671875000000,
+        },
+        0xea9e...0xea9f,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.9556840077071291,
+            .group_height = 2.4674698795180725,
+            .group_x = 0.2137931034482759,
+            .group_y = 0.3066406250000000,
+        },
+        0xeaa2,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.2412121212121212,
+            .group_height = 1.0591799039527152,
+            .group_x = 0.0683593750000000,
+            .group_y = 0.0146484375000000,
+        },
+        0xeab4,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0049115913555993,
+            .group_height = 1.8998144712430427,
+            .group_y = 0.2026367187500000,
+        },
+        0xeab5,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.8979591836734695,
+            .group_height = 1.0054000981836033,
+            .group_x = 0.2023460410557185,
+            .group_y = 0.0053710937500000,
+        },
+        0xeab6,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.8979591836734695,
+            .group_height = 1.0054000981836033,
+            .group_x = 0.2707722385141740,
+        },
+        0xeab7,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0049115913555993,
+            .group_height = 1.8980537534754403,
+            .group_x = 0.0048875855327468,
+            .group_y = 0.2709960937500000,
+        },
+        0xead4...0xead5,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.4152542372881356,
+            .group_x = 0.1486118671747414,
+        },
+        0xead6,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_height = 1.1390433815350389,
+            .group_y = 0.0688476562500000,
+        },
+        0xeb43,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.3635153129161119,
+            .group_height = 1.0002360944082516,
+            .group_x = 0.1992187500000000,
+            .group_y = 0.0002360386808388,
+        },
+        0xeb6e,
+        0xeb71,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_height = 2.0197238658777121,
+            .group_y = 0.2524414062500000,
+        },
+        0xeb6f,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 2.0098619329388558,
+            .group_x = 0.2492639842983317,
+        },
+        0xeb70,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 2.0098619329388558,
+            .group_height = 1.0039215686274510,
+            .group_x = 0.2492639842983317,
+            .group_y = 0.0039062500000000,
+        },
+        0xeb8a,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 2.8826979472140764,
+            .group_height = 2.9804097167804766,
+            .group_x = 0.2634791454730417,
+            .group_y = 0.3314678485576923,
+        },
+        0xeb9a,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.1441340782122904,
+            .group_height = 1.0591799039527152,
+            .group_x = 0.0683593750000000,
+            .group_y = 0.0146484375000000,
+        },
+        0xebd5,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0723270440251573,
+            .group_height = 1.0728129910948141,
+            .group_y = 0.0678710937500000,
+        },
+        0xebd7,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_height = 1.0000418544302916,
+            .group_y = 0.0000418526785714,
+        },
+        0xec07,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 2.8615369874243446,
+            .group_height = 2.9789458113505249,
+            .group_x = 0.2609446802539727,
+            .group_y = 0.3313029661016949,
+        },
+        0xec0b,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0722513089005237,
+            .group_height = 1.0002360944082516,
+            .group_y = 0.0002360386808388,
+        },
+        0xec0c,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.2487804878048780,
+            .group_x = 0.1992187500000000,
+        },
+        0xf019,
+        0xf08c,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0004882812500000,
+        },
+        0xf030,
+        0xf03e,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0004882812500000,
+            .group_height = 1.1428571428571428,
+            .group_y = 0.0625000000000000,
+        },
+        0xf03d,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0004882812500000,
+            .group_height = 1.5014662756598240,
+            .group_y = 0.1669921875000000,
+        },
+        0xf03f,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.6018762826150690,
+            .group_x = 0.1876220107369448,
+        },
+        0xf040,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0006976906439684,
+            .group_height = 1.0001808776182035,
+            .group_x = 0.0006972042111134,
+            .group_y = 0.0001808449074074,
+        },
+        0xf044,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.1029147024980515,
+            .group_height = 1.1024142703367676,
+            .group_x = 0.0463592039005675,
+            .group_y = 0.0430325010461710,
+        },
+        0xf04a,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0004882812500000,
+            .group_height = 1.3312975252838291,
+            .group_y = 0.1245571402616279,
+        },
+        0xf051,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.6007812500000000,
+            .group_height = 1.3312170271945341,
+            .group_x = 0.1874084919472914,
+            .group_y = 0.1245117187500000,
+        },
+        0xf052,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.1436671384194865,
+            .group_height = 1.1430165816326530,
+            .group_x = 0.0624629273607646,
+            .group_y = 0.0625610266424885,
+        },
+        0xf053,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.8765709864847797,
+            .group_height = 1.0707191397207079,
+            .group_x = 0.2332599943628554,
+            .group_y = 0.0332682382480123,
+        },
+        0xf05a...0xf05b,
+        0xf081,
+        0xf092,
+        0xf0aa,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0005935142780173,
+            .group_height = 1.0001395089285714,
+            .group_y = 0.0000697447342726,
+        },
+        0xf071,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0014662756598240,
+            .group_height = 1.1428571428571428,
+            .group_x = 0.0004880429477794,
+            .group_y = 0.0625000000000000,
+        },
+        0xf078,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0717654378877508,
+            .group_height = 1.8757195185766613,
+            .group_x = 0.0331834301604062,
+            .group_y = 0.1670386385827870,
+        },
+        0xf07b,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_height = 1.1428571428571428,
+            .group_y = 0.0625000000000000,
+        },
+        0xf09c,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_height = 1.0810546875000000,
+        },
+        0xf09f,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.7506617925122907,
+            .group_height = 1.0810546875000000,
+            .group_x = 0.2143937211981567,
+        },
+        0xf0a1,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0009775171065494,
+            .group_x = 0.0004882812500000,
+        },
+        0xf0a2,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.1433271023627367,
+            .group_height = 1.0001395089285714,
+            .group_x = 0.0624235731978609,
+            .group_y = 0.0000697447342726,
+        },
+        0xf0a3,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0005760656161586,
+            .group_height = 1.0001220681837999,
+            .group_x = 0.0004792774839344,
+            .group_y = 0.0000610266424885,
+        },
+        0xf0a4,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0005935142780173,
+            .group_height = 1.3335193452380951,
+            .group_y = 0.1250523085507044,
+        },
+        0xf0ca,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0005935142780173,
+            .group_height = 1.1922501247297521,
+            .group_y = 0.0806249128190822,
+        },
+        0xf0d6,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_height = 1.5014662756598240,
+            .group_y = 0.1669921875000000,
+        },
+        0xf0de,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.2253421114919656,
+            .group_height = 2.5216400911161729,
+            .group_x = 0.0918898809523810,
+            .group_y = 0.6034327009936766,
+        },
+        0xf0e7,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.3336843856081169,
+            .group_x = 0.1247597299147187,
+        },
+        0xf296,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0005148743038617,
+            .group_height = 1.0385966606705219,
+            .group_x = 0.0005146093447336,
+            .group_y = 0.0186218440507742,
+        },
+        0xf2c2...0xf2c3,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0000770970394737,
+            .group_height = 1.2864321608040201,
+            .group_y = 0.1113281250000000,
+        },
+        0xf2c4,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0344231791600214,
+            .group_x = 0.0166002826673519,
+        },
+        0xf2c5,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0004538836055876,
+            .group_height = 1.4840579710144928,
+            .group_x = 0.0004536776887225,
+            .group_y = 0.1630859375000000,
+        },
+        0xf2f0,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.0005935142780173,
+            .group_height = 1.0334438518091393,
+            .group_y = 0.0161807783512345,
+        },
+        0xf306,
+        => .{
+            .size_horizontal = .fit,
+            .size_vertical = .fit,
+            .height = .icon,
+            .align_horizontal = .center,
+            .align_vertical = .center,
+            .group_width = 1.2427184466019416,
+            .group_x = 0.0976562500000000,
+        },
         else => .none,
     };
 }

src/font/nerd_font_codegen.py

@@ -7,11 +7,16 @@ attributes and scaling rules.
 This does include an `eval` call! This is spooky, but we trust the nerd fonts code to
 be safe and not malicious or anything.
 
-This script requires Python 3.12 or greater.
+This script requires Python 3.12 or greater, requires that the `fontTools`
+python module is installed, and requires that the path to a copy of the
+SymbolsNerdFontMono font is passed as the first argument to the script.
 """
 
 import ast
+import sys
 import math
+from fontTools.ttLib import TTFont
+from fontTools.pens.boundsPen import BoundsPen
 from collections import defaultdict
 from contextlib import suppress
 from pathlib import Path
@@ -19,7 +24,18 @@ from types import SimpleNamespace
 from typing import Literal, TypedDict, cast
 
 type PatchSetAttributes = dict[Literal["default"] | int, PatchSetAttributeEntry]
-type AttributeHash = tuple[str | None, str | None, str, float, float, float]
+type AttributeHash = tuple[
+    str | None,
+    str | None,
+    str,
+    float,
+    float,
+    float,
+    float,
+    float,
+    float,
+    float,
+]
 type ResolvedSymbol = PatchSetAttributes | PatchSetScaleRules | int | None
 
 
@@ -34,6 +50,11 @@ class PatchSetAttributeEntry(TypedDict):
     stretch: str
     params: dict[str, float | bool]
 
+    group_x: float
+    group_y: float
+    group_width: float
+    group_height: float
+
 
 class PatchSet(TypedDict):
     SymStart: int
@@ -137,6 +158,10 @@ def attr_key(attr: PatchSetAttributeEntry) -> AttributeHash:
         float(params.get("overlap", 0.0)),
         float(params.get("xy-ratio", -1.0)),
         float(params.get("ypadding", 0.0)),
+        float(attr.get("group_x", 0.0)),
+        float(attr.get("group_y", 0.0)),
+        float(attr.get("group_width", 1.0)),
+        float(attr.get("group_height", 1.0)),
     )
 
 
@@ -162,6 +187,11 @@ def emit_zig_entry_multikey(codepoints: list[int], attr: PatchSetAttributeEntry)
     stretch = attr.get("stretch", "")
     params = attr.get("params", {})
 
+    group_x = attr.get("group_x", 0.0)
+    group_y = attr.get("group_y", 0.0)
+    group_width = attr.get("group_width", 1.0)
+    group_height = attr.get("group_height", 1.0)
+
     overlap = params.get("overlap", 0.0)
     xy_ratio = params.get("xy-ratio", -1.0)
     y_padding = params.get("ypadding", 0.0)
@@ -192,7 +222,6 @@ def emit_zig_entry_multikey(codepoints: list[int], attr: PatchSetAttributeEntry)
     if "^" not in stretch:
         s += "            .height = .icon,\n"
 
-
     # There are two cases where we want to limit the constraint width to 1:
     # - If there's a `1` in the stretch mode string.
     # - If the stretch mode is `xy` and there's not an explicit `2`.
@@ -204,6 +233,15 @@ def emit_zig_entry_multikey(codepoints: list[int], attr: PatchSetAttributeEntry)
     if valign is not None:
         s += f"            .align_vertical = {valign},\n"
 
+    if group_width != 1.0:
+        s += f"            .group_width = {group_width:.16f},\n"
+    if group_height != 1.0:
+        s += f"            .group_height = {group_height:.16f},\n"
+    if group_x != 0.0:
+        s += f"            .group_x = {group_x:.16f},\n"
+    if group_y != 0.0:
+        s += f"            .group_y = {group_y:.16f},\n"
+
     # `overlap` and `ypadding` are mutually exclusive,
     # this is asserted in the nerd fonts patcher itself.
     if overlap:
@@ -226,16 +264,53 @@ def emit_zig_entry_multikey(codepoints: list[int], attr: PatchSetAttributeEntry)
     return s
 
 
-def generate_zig_switch_arms(patch_sets: list[PatchSet]) -> str:
+def generate_zig_switch_arms(
+    patch_sets: list[PatchSet],
+    nerd_font: TTFont,
+) -> str:
+    cmap = nerd_font.getBestCmap()
+    glyphs = nerd_font.getGlyphSet()
+
     entries: dict[int, PatchSetAttributeEntry] = {}
     for entry in patch_sets:
         attributes = entry["Attributes"]
 
         for cp in range(entry["SymStart"], entry["SymEnd"] + 1):
-            entries[cp] = attributes["default"]
+            entries[cp] = attributes["default"].copy()
 
         entries |= {k: v for k, v in attributes.items() if isinstance(k, int)}
 
+        if entry["ScaleRules"] is not None and "ScaleGroups" in entry["ScaleRules"]:
+            for group in entry["ScaleRules"]["ScaleGroups"]:
+                xMin = math.inf
+                yMin = math.inf
+                xMax = -math.inf
+                yMax = -math.inf
+                individual_bounds: dict[int, tuple[int, int, int ,int]] = {}
+                for cp in group:
+                    if cp not in cmap:
+                        continue
+                    glyph = glyphs[cmap[cp]]
+                    bounds = BoundsPen(glyphSet=glyphs)
+                    glyph.draw(bounds)
+                    individual_bounds[cp] = bounds.bounds
+                    xMin = min(bounds.bounds[0], xMin)
+                    yMin = min(bounds.bounds[1], yMin)
+                    xMax = max(bounds.bounds[2], xMax)
+                    yMax = max(bounds.bounds[3], yMax)
+                group_width = xMax - xMin
+                group_height = yMax - yMin
+                for cp in group:
+                    if cp not in cmap or cp not in entries:
+                        continue
+                    this_bounds = individual_bounds[cp]
+                    this_width = this_bounds[2] - this_bounds[0]
+                    this_height = this_bounds[3] - this_bounds[1]
+                    entries[cp]["group_width"] = group_width / this_width
+                    entries[cp]["group_height"] = group_height / this_height
+                    entries[cp]["group_x"] = (this_bounds[0] - xMin) / group_width
+                    entries[cp]["group_y"] = (this_bounds[1] - yMin) / group_height
+
     del entries[0]
 
     # Group codepoints by attribute key
@@ -256,6 +331,10 @@ def generate_zig_switch_arms(patch_sets: list[PatchSet]) -> str:
 if __name__ == "__main__":
     project_root = Path(__file__).resolve().parents[2]
 
+    nf_path = sys.argv[1]
+
+    nerd_font = TTFont(nf_path)
+
     patcher_path = project_root / "vendor" / "nerd-fonts" / "font-patcher.py"
     source = patcher_path.read_text(encoding="utf-8")
     patch_set = extract_patch_set_values(source)
@@ -275,5 +354,5 @@ const Constraint = @import("face.zig").RenderOptions.Constraint;
 pub fn getConstraint(cp: u21) Constraint {
     return switch (cp) {
 """)
-        f.write(generate_zig_switch_arms(patch_set))
+        f.write(generate_zig_switch_arms(patch_set, nerd_font))
         f.write("\n        else => .none,\n    };\n}\n")