screencapturekit 3.0.1

//! Pixel format enumeration
//!
//! Defines the available pixel formats for captured frames.

use core::fmt;
use std::fmt::{Display, Formatter};

use crate::utils::four_char_code::FourCharCode;

/// Pixel format for captured video frames
///
/// Specifies the layout and encoding of pixel data in captured frames.
///
/// This enum is `#[non_exhaustive]`. Apple may add new pixel formats in
/// future macOS releases; downstream code that exhaustively matches on
/// `PixelFormat` must include a wildcard arm. Pixel formats this crate
/// does not yet recognise are surfaced via the [`PixelFormat::Unknown`]
/// variant rather than being silently coerced to [`PixelFormat::BGRA`]
/// (which would mislead callers that branch on the format).
///
/// # Equality and hashing
///
/// `PixelFormat` compares and hashes by its underlying [`FourCharCode`]
/// rather than by enum variant. This means
/// `PixelFormat::BGRA == PixelFormat::Unknown(FourCharCode::from_bytes(*b"BGRA"))`
/// — both round-trip to the same wire-level format — and they hash the
/// same. Without this normalisation, the user-facing `Unknown(known_code)`
/// footgun (constructing the variant with a code that already maps to a
/// named variant) would silently produce two `PixelFormat` values that
/// represent the same underlying format but compared unequal and indexed
/// `HashMap`s twice.
///
/// # Examples
///
/// ```
/// use screencapturekit::stream::configuration::PixelFormat;
/// use screencapturekit::FourCharCode;
///
/// let format = PixelFormat::BGRA;
/// println!("Format: {}", format); // Prints "BGRA"
///
/// // Equality normalises through FourCharCode:
/// let synonym = PixelFormat::Unknown(FourCharCode::from_bytes(*b"BGRA"));
/// assert_eq!(PixelFormat::BGRA, synonym);
/// ```
#[allow(non_camel_case_types)]
#[derive(Debug, Clone, Copy, Default)]
#[non_exhaustive]
pub enum PixelFormat {
    /// Packed little endian ARGB8888 (most common)
    #[default]
    BGRA,
    /// Packed little endian ARGB2101010 (10-bit color)
    l10r,
    /// Two-plane "video" range YCbCr 4:2:0
    YCbCr_420v,
    /// Two-plane "full" range YCbCr 4:2:0
    YCbCr_420f,
    /// Two-plane "full" range `YCbCr10` 4:4:4 (10-bit)
    xf44,
    /// 64-bit RGBA IEEE half-precision float, 16-bit little-endian (HDR)
    RGhA,
    /// A pixel format reported by `ScreenCaptureKit` that this crate does not
    /// model as a named variant. The wrapped [`FourCharCode`] preserves the
    /// raw four-character code so callers can branch on it explicitly or
    /// log it for diagnostics.
    Unknown(FourCharCode),
}

// `PixelFormat` is `Eq`/`Hash` via its underlying FourCharCode so that
// `Unknown(known_code)` and the corresponding named variant compare and
// hash identically. See the type-level docs for the rationale.
impl PartialEq for PixelFormat {
    fn eq(&self, other: &Self) -> bool {
        FourCharCode::from(*self) == FourCharCode::from(*other)
    }
}

impl Eq for PixelFormat {}

impl std::hash::Hash for PixelFormat {
    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
        FourCharCode::from(*self).hash(state);
    }
}
impl Display for PixelFormat {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        let c: FourCharCode = (*self).into();
        write!(f, "{}", c.display())
    }
}

impl From<PixelFormat> for FourCharCode {
    fn from(val: PixelFormat) -> Self {
        // Use infallible byte array constructor for compile-time constants
        match val {
            PixelFormat::BGRA => Self::from_bytes(*b"BGRA"),
            PixelFormat::l10r => Self::from_bytes(*b"l10r"),
            PixelFormat::YCbCr_420v => Self::from_bytes(*b"420v"),
            PixelFormat::YCbCr_420f => Self::from_bytes(*b"420f"),
            PixelFormat::xf44 => Self::from_bytes(*b"xf44"),
            PixelFormat::RGhA => Self::from_bytes(*b"RGhA"),
            PixelFormat::Unknown(code) => code,
        }
    }
}
impl From<u32> for PixelFormat {
    fn from(value: u32) -> Self {
        // FourCharCode stores u32 directly, no byte conversion needed
        let c = FourCharCode::from_u32(value);
        c.into()
    }
}
impl From<FourCharCode> for PixelFormat {
    fn from(val: FourCharCode) -> Self {
        match val.display().as_str() {
            "BGRA" => Self::BGRA,
            "l10r" => Self::l10r,
            "420v" => Self::YCbCr_420v,
            "420f" => Self::YCbCr_420f,
            "xf44" => Self::xf44,
            "RGhA" => Self::RGhA,
            // Preserve the raw code rather than silently coercing to BGRA.
            // Callers that branched on the format would otherwise misread
            // YUV/HDR/etc. samples as BGRA.
            _ => Self::Unknown(val),
        }
    }
}