font: CodepointResolver style disabling test

src/font/CodepointResolver.zig

@@ -72,6 +72,15 @@ pub fn deinit(self: *CodepointResolver, alloc: Allocator) void {
 /// presentation for the codepoint.
 /// a code point.
 ///
+/// An allocator is required because certain functionality (codepoint
+/// mapping, fallback fonts, etc.) may require memory allocation. Curiously,
+/// this function cannot error! If an error occurs for any reason, including
+/// memory allocation, the associated functionality is ignored and the
+/// resolver attempts to use a different method to satisfy the codepoint.
+/// This behavior is intentional to make the resolver apply best-effort
+/// logic to satisfy the codepoint since its better to render something
+/// than nothing.
+///
 /// This logic is relatively complex so the exact algorithm is documented
 /// here. If this gets out of sync with the code, ask questions.
 ///
@@ -118,7 +127,7 @@ pub fn getIndex(
     }
 
     // Codepoint overrides.
-    if (self.indexForCodepointOverride(alloc, cp)) |idx_| {
+    if (self.getIndexCodepointOverride(alloc, cp)) |idx_| {
         if (idx_) |idx| return idx;
     } else |err| {
         log.warn("codepoint override failed codepoint={} err={}", .{ cp, err });
@@ -208,7 +217,7 @@ pub fn getIndex(
 
 /// Checks if the codepoint is in the map of codepoint overrides,
 /// finds the override font, and returns it.
-fn indexForCodepointOverride(
+fn getIndexCodepointOverride(
     self: *CodepointResolver,
     alloc: Allocator,
     cp: u32,
@@ -265,7 +274,7 @@ fn indexForCodepointOverride(
     const idx = idx_ orelse return null;
 
     // We need to verify that this index has the codepoint we want.
-    if (self.collection.hasCodepoint(idx, cp, null)) {
+    if (self.collection.hasCodepoint(idx, cp, .{ .any = {} })) {
         log.debug("codepoint override based on config codepoint={} family={s}", .{
             cp,
             desc.family orelse "",
@@ -385,3 +394,59 @@ test getIndex {
         try testing.expect(r.getIndex(alloc, 0x1FB00, .regular, null) == null);
     }
 }
+
+test "getIndex disabled font style" {
+    const testing = std.testing;
+    const alloc = testing.allocator;
+    const testFont = @import("test.zig").fontRegular;
+
+    var atlas_greyscale = try font.Atlas.init(alloc, 512, .greyscale);
+    defer atlas_greyscale.deinit(alloc);
+
+    var lib = try Library.init();
+    defer lib.deinit();
+
+    var c = try Collection.init(alloc);
+    c.load_options = .{ .library = lib };
+
+    _ = try c.add(alloc, .regular, .{ .loaded = try Face.init(
+        lib,
+        testFont,
+        .{ .size = .{ .points = 12, .xdpi = 96, .ydpi = 96 } },
+    ) });
+    _ = try c.add(alloc, .bold, .{ .loaded = try Face.init(
+        lib,
+        testFont,
+        .{ .size = .{ .points = 12, .xdpi = 96, .ydpi = 96 } },
+    ) });
+    _ = try c.add(alloc, .italic, .{ .loaded = try Face.init(
+        lib,
+        testFont,
+        .{ .size = .{ .points = 12, .xdpi = 96, .ydpi = 96 } },
+    ) });
+
+    var r: CodepointResolver = .{ .collection = c };
+    defer r.deinit(alloc);
+    r.styles.set(.bold, false); // Disable bold
+
+    // Regular should work fine
+    {
+        const idx = r.getIndex(alloc, 'A', .regular, null).?;
+        try testing.expectEqual(Style.regular, idx.style);
+        try testing.expectEqual(@as(Collection.Index.IndexInt, 0), idx.idx);
+    }
+
+    // Bold should go to regular
+    {
+        const idx = r.getIndex(alloc, 'A', .bold, null).?;
+        try testing.expectEqual(Style.regular, idx.style);
+        try testing.expectEqual(@as(Collection.Index.IndexInt, 0), idx.idx);
+    }
+
+    // Italic should still work
+    {
+        const idx = r.getIndex(alloc, 'A', .italic, null).?;
+        try testing.expectEqual(Style.italic, idx.style);
+        try testing.expectEqual(@as(Collection.Index.IndexInt, 0), idx.idx);
+    }
+}

src/font/Collection.zig

@@ -18,6 +18,7 @@ const Collection = @This();
 const std = @import("std");
 const Allocator = std.mem.Allocator;
 const font = @import("main.zig");
+const options = font.options;
 const DeferredFace = font.DeferredFace;
 const DesiredSize = font.face.DesiredSize;
 const Face = font.Face;
@@ -160,14 +161,11 @@ pub fn hasCodepoint(
     self: *const Collection,
     index: Index,
     cp: u32,
-    p: ?Presentation,
+    p_mode: PresentationMode,
 ) bool {
     const list = self.faces.get(index.style);
     if (index.idx >= list.items.len) return false;
-    return list.items[index.idx].hasCodepoint(
-        cp,
-        if (p) |v| .{ .explicit = v } else .{ .any = {} },
-    );
+    return list.items[index.idx].hasCodepoint(cp, p_mode);
 }
 
 /// Automatically create an italicized font from the regular
@@ -601,3 +599,50 @@ test setSize {
     try c.setSize(.{ .points = 24 });
     try testing.expectEqual(@as(u32, 24), c.load_options.?.size.points);
 }
+
+test hasCodepoint {
+    const testing = std.testing;
+    const alloc = testing.allocator;
+    const testFont = @import("test.zig").fontRegular;
+
+    var lib = try Library.init();
+    defer lib.deinit();
+
+    var c = try init(alloc);
+    defer c.deinit(alloc);
+    c.load_options = .{ .library = lib };
+
+    const idx = try c.add(alloc, .regular, .{ .loaded = try Face.init(
+        lib,
+        testFont,
+        .{ .size = .{ .points = 12, .xdpi = 96, .ydpi = 96 } },
+    ) });
+
+    try testing.expect(c.hasCodepoint(idx, 'A', .{ .any = {} }));
+    try testing.expect(!c.hasCodepoint(idx, '🥸', .{ .any = {} }));
+}
+
+test "hasCodepoint emoji default graphical" {
+    if (options.backend != .fontconfig_freetype) return error.SkipZigTest;
+
+    const testing = std.testing;
+    const alloc = testing.allocator;
+    const testEmoji = @import("test.zig").fontEmoji;
+
+    var lib = try Library.init();
+    defer lib.deinit();
+
+    var c = try init(alloc);
+    defer c.deinit(alloc);
+    c.load_options = .{ .library = lib };
+
+    const idx = try c.add(alloc, .regular, .{ .loaded = try Face.init(
+        lib,
+        testEmoji,
+        .{ .size = .{ .points = 12, .xdpi = 96, .ydpi = 96 } },
+    ) });
+
+    try testing.expect(!c.hasCodepoint(idx, 'A', .{ .any = {} }));
+    try testing.expect(c.hasCodepoint(idx, '🥸', .{ .any = {} }));
+    // TODO(fontmem): test explicit/implicit
+}