playdate-kit/Sources/PlaydateKit/Graphics/Structures/Pattern.swift

extension Graphics {
    /// An 8×8 two-color pattern: 8 rows of image data followed by 8 rows of mask.
    public struct Pattern: Sendable {
        /// The pattern's 8 rows of image data followed by 8 rows of mask,
        /// one byte per row.
        public var bytes: (UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8,
                           UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8)

        /// Creates a pattern from 8 rows of image data and 8 rows of mask.
        public init(bytes: (UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8,
                            UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8)) {
            self.bytes = bytes
        }

        /// Creates an opaque pattern from 8 rows of image data.
        public init(rows r: (UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8)) {
            bytes = (r.0, r.1, r.2, r.3, r.4, r.5, r.6, r.7,
                     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff)
        }
    }
}

// InlineArray needs macOS 26 on the host, so these conveniences are gated
// there while the tuple API keeps working on older systems. The device and
// Linux have no such restriction. Both representations are 16 contiguous
// bytes, so converting between them is a reinterpretation, not a copy.
@available(macOS 26, *)
extension Graphics.Pattern {
    /// Creates a pattern from 8 rows of image data and 8 rows of mask.
    public init(bytes: [16 of UInt8]) {
        self.init(bytes: unsafeBitCast(bytes, to: Bytes.self))
    }

    /// Creates an opaque pattern from 8 rows of image data.
    public init(rows: [8 of UInt8]) {
        self.init(bytes: [16 of UInt8] { $0 < 8 ? rows[$0] : 0xff })
    }

    /// The pattern's bytes as an inline array: 8 rows of image data
    /// followed by 8 rows of mask.
    public var inlineBytes: [16 of UInt8] {
        get { unsafeBitCast(bytes, to: [16 of UInt8].self) }
        set { bytes = unsafeBitCast(newValue, to: Bytes.self) }
    }
}

extension Graphics.Pattern {
    typealias Bytes = (UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8,
                       UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8)
}