font: use explicit error sets where we can

src/font/Atlas.zig

@@ -83,7 +83,7 @@ pub const Region = extern struct {
     height: u32,
 };
 
-pub fn init(alloc: Allocator, size: u32, format: Format) !Atlas {
+pub fn init(alloc: Allocator, size: u32, format: Format) Allocator.Error!Atlas {
     var result = Atlas{
         .data = try alloc.alloc(u8, size * size * format.depth()),
         .size = size,
@@ -111,7 +111,12 @@ pub fn deinit(self: *Atlas, alloc: Allocator) void {
 ///
 /// May allocate to add a new rectangle into the internal list of rectangles.
 /// This will not automatically enlarge the texture if it is full.
-pub fn reserve(self: *Atlas, alloc: Allocator, width: u32, height: u32) !Region {
+pub fn reserve(
+    self: *Atlas,
+    alloc: Allocator,
+    width: u32,
+    height: u32,
+) (Allocator.Error || Error)!Region {
     // x, y are populated within :best_idx below
     var region: Region = .{ .x = 0, .y = 0, .width = width, .height = height };
 
@@ -310,9 +315,9 @@ pub fn dump(self: Atlas, writer: anytype) !void {
             .grayscale => '5',
             .rgb => '6',
             else => {
-                log.err("Unsupported format for dump: {}", .{ self.format });
+                log.err("Unsupported format for dump: {}", .{self.format});
                 @panic("Cannot dump this atlas format.");
-            }
+            },
         }),
         self.size,
         self.size,

src/font/sprite/canvas.zig

@@ -102,7 +102,11 @@ pub const Canvas = struct {
     }
 
     /// Write the data in this drawing to the atlas.
-    pub fn writeAtlas(self: *Canvas, alloc: Allocator, atlas: *font.Atlas) !font.Atlas.Region {
+    pub fn writeAtlas(
+        self: *Canvas,
+        alloc: Allocator,
+        atlas: *font.Atlas,
+    ) (Allocator.Error || font.Atlas.Error)!font.Atlas.Region {
         assert(atlas.format == .grayscale);
 
         const width = @as(u32, @intCast(self.sfc.getWidth()));