Enum PixelMode

Source

#[repr(u8)]pub enum PixelMode {
    Mono1 = 0,
    Mono8 = 1,
    Rgb8 = 2,
    Bgr8 = 3,
    Xbgr8 = 4,
    Cmyk8 = 5,
    DeviceN8 = 6,
}

Expand description

Re-export every public type from the color crate, including all arithmetic helpers from color::convert.

Downstream modules within this crate can import everything they need with a single use crate::types::*. Pixel color mode, describing the memory layout of one pixel in a bitmap row.

The discriminant values mirror SplashColorMode in SplashTypes.h so that raw FFI conversions remain stable.

§Packed-bits exception

Mono1 stores one bit per pixel and cannot be expressed as a whole-number byte count per pixel. See PixelMode::is_packed_bits and PixelMode::bits_per_pixel.

Variants§

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Mono1 = 0

1 bit/pixel, MSB-first packed; row stride is (width + 7) / 8 bytes.

bytes_per_pixel() returns 0 for this variant — guard with is_packed_bits before using it.

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Mono8 = 1

1 byte/pixel grayscale (8 bits, luminance only).

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Rgb8 = 2

3 bytes/pixel, channel order: R G B.

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Bgr8 = 3

3 bytes/pixel, channel order: B G R.

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Xbgr8 = 4

4 bytes/pixel, channel order: X B G R, where X = 255. Used by the Cairo and Qt/QImage backends.

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Cmyk8 = 5

4 bytes/pixel: C M Y K.

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DeviceN8 = 6

8 bytes/pixel: C M Y K + 4 spot channels. Corresponds to SPOT_NCOMPS = 4 in SplashTypes.h.

Implementations§

Source §

impl PixelMode

Source

pub const fn bytes_per_pixel(self) -> usize

Returns the number of bytes occupied by a single pixel in this mode.

§Packed-bits exception

Returns 0 for Mono1. Callers must check is_packed_bits before dividing or multiplying by this value, or use pixel_count_to_bytes which handles the case safely.

§Exhaustiveness

The implementation uses an exhaustive match, so adding a new variant without updating this function is a compile error.

Source

pub const fn bits_per_pixel(self) -> usize

Returns the number of bits per pixel for this mode.

Unlike bytes_per_pixel, this method always returns a meaningful positive value, making it safe to use for Mono1 without a prior guard.

Mode	Bits
`Mono1`	1
`Mono8`	8
`Rgb8`	24
`Bgr8`	24
`Xbgr8`	32
`Cmyk8`	32
`DeviceN8`	64

Source

pub const fn is_packed_bits(self) -> bool

Returns true if pixels are packed at sub-byte granularity.

Currently only Mono1 is packed. For packed modes, bytes_per_pixel returns 0 and must not be used for per-pixel arithmetic; use the row-stride formula (width + 7) / 8 instead.

Source

pub const fn from_u8(v: u8) -> Option<PixelMode>

Converts a raw discriminant byte into a PixelMode, or None if the value does not correspond to any variant.

Prefer this over unsafe transmute or unchecked as casts when parsing mode values from untrusted sources (e.g. C FFI, file headers).

assert_eq!(PixelMode::from_u8(2), Some(PixelMode::Rgb8));
assert_eq!(PixelMode::from_u8(99), None);

Source

pub const fn pixel_count_to_bytes(self, count: usize) -> Option<usize>

Multiplies count pixels by bytes_per_pixel, returning None on overflow or when the mode is Mono1 (packed bits have no per-pixel byte count).

Use this instead of count * mode.bytes_per_pixel() to avoid panics or silent overflow in release builds.

assert_eq!(PixelMode::Rgb8.pixel_count_to_bytes(10), Some(30));
assert_eq!(PixelMode::Mono1.pixel_count_to_bytes(10), None);
assert_eq!(PixelMode::Rgb8.pixel_count_to_bytes(usize::MAX), None);