Struct png::Transformations

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pub struct Transformations { /* private fields */ }

Expand description

Output transformations

Many flags from libpng are not yet supported. A PR discussing/adding them would be nice.

/// Discard the alpha channel
const STRIP_ALPHA         = 0x0002; // read only
/// Expand 1; 2 and 4-bit samples to bytes
const PACKING             = 0x0004; // read and write
/// Change order of packed pixels to LSB first
const PACKSWAP            = 0x0008; // read and write
/// Invert monochrome images
const INVERT_MONO         = 0x0020; // read and write
/// Normalize pixels to the sBIT depth
const SHIFT               = 0x0040; // read and write
/// Flip RGB to BGR; RGBA to BGRA
const BGR                 = 0x0080; // read and write
/// Flip RGBA to ARGB or GA to AG
const SWAP_ALPHA          = 0x0100; // read and write
/// Byte-swap 16-bit samples
const SWAP_ENDIAN         = 0x0200; // read and write
/// Change alpha from opacity to transparency
const INVERT_ALPHA        = 0x0400; // read and write
const STRIP_FILLER        = 0x0800; // write only
const STRIP_FILLER_BEFORE = 0x0800; // write only
const STRIP_FILLER_AFTER  = 0x1000; // write only
const GRAY_TO_RGB         = 0x2000; // read only
const EXPAND_16           = 0x4000; // read only
/// Similar to STRIP_16 but in libpng considering gamma?
/// Not entirely sure the documentation says it is more
/// accurate but doesn't say precisely how.
const SCALE_16            = 0x8000; // read only

Implementations§

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impl Transformations

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pub const IDENTITY: Self = _

No transformation

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pub const STRIP_16: Self = _

Strip 16-bit samples to 8 bits

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pub const EXPAND: Self = _

Expand paletted images to RGB; expand grayscale images of less than 8-bit depth to 8-bit depth; and expand tRNS chunks to alpha channels.

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pub const ALPHA: Self = _

Expand paletted images to include an alpha channel. Implies EXPAND.

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pub const fn empty() -> Self

Returns an empty set of flags.

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pub const fn all() -> Self

Returns the set containing all flags.

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pub const fn bits(&self) -> u32

Returns the raw value of the flags currently stored.

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pub const fn from_bits(bits: u32) -> Option<Self>

Convert from underlying bit representation, unless that representation contains bits that do not correspond to a flag.

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pub const fn from_bits_truncate(bits: u32) -> Self

Convert from underlying bit representation, dropping any bits that do not correspond to flags.

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pub const unsafe fn from_bits_unchecked(bits: u32) -> Self

Convert from underlying bit representation, preserving all bits (even those not corresponding to a defined flag).

§Safety

The caller of the bitflags! macro can chose to allow or disallow extra bits for their bitflags type.

The caller of from_bits_unchecked() has to ensure that all bits correspond to a defined flag or that extra bits are valid for this bitflags type.

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pub const fn is_empty(&self) -> bool

Returns true if no flags are currently stored.

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pub const fn is_all(&self) -> bool

Returns true if all flags are currently set.

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pub const fn intersects(&self, other: Self) -> bool

Returns true if there are flags common to both self and other.

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pub const fn contains(&self, other: Self) -> bool

Returns true if all of the flags in other are contained within self.

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pub fn insert(&mut self, other: Self)

Inserts the specified flags in-place.

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pub fn remove(&mut self, other: Self)

Removes the specified flags in-place.

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pub fn toggle(&mut self, other: Self)

Toggles the specified flags in-place.

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pub fn set(&mut self, other: Self, value: bool)

Inserts or removes the specified flags depending on the passed value.

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pub const fn intersection(self, other: Self) -> Self

Returns the intersection between the flags in self and other.

Specifically, the returned set contains only the flags which are present in both self and other.

This is equivalent to using the & operator (e.g. ops::BitAnd), as in flags & other.

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pub const fn union(self, other: Self) -> Self

Returns the union of between the flags in self and other.

Specifically, the returned set contains all flags which are present in either self or other, including any which are present in both (see Self::symmetric_difference if that is undesirable).

This is equivalent to using the | operator (e.g. ops::BitOr), as in flags | other.

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pub const fn difference(self, other: Self) -> Self

Returns the difference between the flags in self and other.

Specifically, the returned set contains all flags present in self, except for the ones present in other.

It is also conceptually equivalent to the “bit-clear” operation: flags & !other (and this syntax is also supported).

This is equivalent to using the - operator (e.g. ops::Sub), as in flags - other.

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pub const fn symmetric_difference(self, other: Self) -> Self

Returns the symmetric difference between the flags in self and other.

Specifically, the returned set contains the flags present which are present in self or other, but that are not present in both. Equivalently, it contains the flags present in exactly one of the sets self and other.

This is equivalent to using the ^ operator (e.g. ops::BitXor), as in flags ^ other.

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