From 2a386daa19e6647914690059e44a7ebbdb378d39 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Mon, 1 Apr 2024 12:49:32 -0700
Subject: [PATCH] font: GroupCacheSet.Key has metric modifiers

---
 src/Surface.zig            | 21 ++-------------------
 src/font/GroupCacheSet.zig | 30 ++++++++++++++++++++++++++++++
 src/font/face/Metrics.zig  | 15 +++++++++++++++
 3 files changed, 47 insertions(+), 19 deletions(-)

diff --git a/src/Surface.zig b/src/Surface.zig
index 36d4c00a4..2efc23fdf 100644
--- a/src/Surface.zig
+++ b/src/Surface.zig
@@ -338,25 +338,8 @@ pub fn init(
     font_group.* = try font.GroupCache.init(alloc, group: {
         var group = try font.Group.init(alloc, font_lib, font_size);
         errdefer group.deinit();
-
-        // Setup our font metric modifiers if we have any.
-        group.metric_modifiers = set: {
-            var set: font.face.Metrics.ModifierSet = .{};
-            errdefer set.deinit(alloc);
-            if (config.@"adjust-cell-width") |m| try set.put(alloc, .cell_width, m);
-            if (config.@"adjust-cell-height") |m| try set.put(alloc, .cell_height, m);
-            if (config.@"adjust-font-baseline") |m| try set.put(alloc, .cell_baseline, m);
-            if (config.@"adjust-underline-position") |m| try set.put(alloc, .underline_position, m);
-            if (config.@"adjust-underline-thickness") |m| try set.put(alloc, .underline_thickness, m);
-            if (config.@"adjust-strikethrough-position") |m| try set.put(alloc, .strikethrough_position, m);
-            if (config.@"adjust-strikethrough-thickness") |m| try set.put(alloc, .strikethrough_thickness, m);
-            break :set set;
-        };
-
-        // If we have codepoint mappings, set those.
-        if (font_group_key.codepoint_map.list.len > 0) {
-            group.codepoint_map = font_group_key.codepoint_map;
-        }
+        group.metric_modifiers = font_group_key.metric_modifiers;
+        group.codepoint_map = font_group_key.codepoint_map;
 
         // Set our styles
         group.styles.set(.bold, config.@"font-style-bold" != .false);
diff --git a/src/font/GroupCacheSet.zig b/src/font/GroupCacheSet.zig
index c1d344947..867658627 100644
--- a/src/font/GroupCacheSet.zig
+++ b/src/font/GroupCacheSet.zig
@@ -19,6 +19,7 @@ const Allocator = std.mem.Allocator;
 const ArenaAllocator = std.heap.ArenaAllocator;
 const fontpkg = @import("main.zig");
 const Style = fontpkg.Style;
+const Metrics = fontpkg.face.Metrics;
 const CodepointMap = fontpkg.CodepointMap;
 const discovery = @import("discovery.zig");
 const configpkg = @import("../config.zig");
@@ -43,6 +44,9 @@ pub const Key = struct {
     /// The codepoint map configuration.
     codepoint_map: CodepointMap,
 
+    /// The metric modifier set configuration.
+    metric_modifiers: Metrics.ModifierSet,
+
     const style_offsets_len = std.enums.directEnumArrayLen(Style, 0);
     const StyleOffsets = [style_offsets_len]usize;
 
@@ -122,6 +126,19 @@ pub const Key = struct {
             break :map clone.map;
         };
 
+        // Metric modifiers
+        const metric_modifiers: Metrics.ModifierSet = set: {
+            var set: Metrics.ModifierSet = .{};
+            if (config.@"adjust-cell-width") |m| try set.put(alloc, .cell_width, m);
+            if (config.@"adjust-cell-height") |m| try set.put(alloc, .cell_height, m);
+            if (config.@"adjust-font-baseline") |m| try set.put(alloc, .cell_baseline, m);
+            if (config.@"adjust-underline-position") |m| try set.put(alloc, .underline_position, m);
+            if (config.@"adjust-underline-thickness") |m| try set.put(alloc, .underline_thickness, m);
+            if (config.@"adjust-strikethrough-position") |m| try set.put(alloc, .strikethrough_position, m);
+            if (config.@"adjust-strikethrough-thickness") |m| try set.put(alloc, .strikethrough_thickness, m);
+            break :set set;
+        };
+
         return .{
             .arena = arena,
             .descriptors = try descriptors.toOwnedSlice(),
@@ -132,6 +149,7 @@ pub const Key = struct {
                 config.@"font-family-bold-italic".list.items.len,
             },
             .codepoint_map = codepoint_map,
+            .metric_modifiers = metric_modifiers,
         };
     }
 
@@ -157,6 +175,16 @@ pub const Key = struct {
         autoHash(hasher, self.descriptors.len);
         for (self.descriptors) |d| d.hash(hasher);
         autoHash(hasher, self.codepoint_map);
+        autoHash(hasher, self.metric_modifiers.count());
+        if (self.metric_modifiers.count() > 0) {
+            inline for (@typeInfo(Metrics.Key).Enum.fields) |field| {
+                const key = @field(Metrics.Key, field.name);
+                if (self.metric_modifiers.get(key)) |value| {
+                    autoHash(hasher, key);
+                    value.hash(hasher);
+                }
+            }
+        }
     }
 
     /// Returns a hash code that can be used to uniquely identify this
@@ -176,4 +204,6 @@ test "Key" {
 
     var k = try Key.init(alloc, &cfg);
     defer k.deinit();
+
+    try testing.expect(k.hashcode() > 0);
 }
diff --git a/src/font/face/Metrics.zig b/src/font/face/Metrics.zig
index e8f318d48..621f0ddbf 100644
--- a/src/font/face/Metrics.zig
+++ b/src/font/face/Metrics.zig
@@ -169,6 +169,21 @@ pub const Modifier = union(enum) {
         };
     }
 
+    /// Hash using the hasher.
+    pub fn hash(self: Modifier, hasher: anytype) void {
+        const autoHash = std.hash.autoHash;
+        autoHash(hasher, std.meta.activeTag(self));
+        switch (self) {
+            // floats can't be hashed directly so we round it to the
+            // nearest int and then hash that. This is not perfect but
+            // hash collisions due to the modifier being wrong are really
+            // rare so we should fix this up later.
+            // TODO(fontmem): make better
+            .percent => |v| autoHash(hasher, @as(i64, @intFromFloat(v))),
+            .absolute => |v| autoHash(hasher, v),
+        }
+    }
+
     test "formatConfig percent" {
         const configpkg = @import("../../config.zig");
         const testing = std.testing;