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//! Chunk types and functions
#![allow(dead_code)]
#![allow(non_upper_case_globals)]
use core::fmt;
#[derive(Clone, Copy, PartialEq, Eq, Hash)]
pub struct ChunkType(pub [u8; 4]);
// -- Critical chunks --
/// Image header
pub const IHDR: ChunkType = ChunkType(*b"IHDR");
/// Palette
pub const PLTE: ChunkType = ChunkType(*b"PLTE");
/// Image data
pub const IDAT: ChunkType = ChunkType(*b"IDAT");
/// Image trailer
pub const IEND: ChunkType = ChunkType(*b"IEND");
// -- Ancillary chunks --
/// Transparency
pub const tRNS: ChunkType = ChunkType(*b"tRNS");
/// Background colour
pub const bKGD: ChunkType = ChunkType(*b"bKGD");
/// Image last-modification time
pub const tIME: ChunkType = ChunkType(*b"tIME");
/// Physical pixel dimensions
pub const pHYs: ChunkType = ChunkType(*b"pHYs");
/// Source system's pixel chromaticities
pub const cHRM: ChunkType = ChunkType(*b"cHRM");
/// Source system's gamma value
pub const gAMA: ChunkType = ChunkType(*b"gAMA");
/// sRGB color space chunk
pub const sRGB: ChunkType = ChunkType(*b"sRGB");
/// ICC profile chunk
pub const iCCP: ChunkType = ChunkType(*b"iCCP");
/// Latin-1 uncompressed textual data
pub const tEXt: ChunkType = ChunkType(*b"tEXt");
/// Latin-1 compressed textual data
pub const zTXt: ChunkType = ChunkType(*b"zTXt");
/// UTF-8 textual data
pub const iTXt: ChunkType = ChunkType(*b"iTXt");
// -- Extension chunks --
/// Animation control
pub const acTL: ChunkType = ChunkType(*b"acTL");
/// Frame control
pub const fcTL: ChunkType = ChunkType(*b"fcTL");
/// Frame data
pub const fdAT: ChunkType = ChunkType(*b"fdAT");
// -- Chunk type determination --
/// Returns true if the chunk is critical.
pub fn is_critical(ChunkType(type_): ChunkType) -> bool {
type_[0] & 32 == 0
}
/// Returns true if the chunk is private.
pub fn is_private(ChunkType(type_): ChunkType) -> bool {
type_[1] & 32 != 0
}
/// Checks whether the reserved bit of the chunk name is set.
/// If it is set the chunk name is invalid.
pub fn reserved_set(ChunkType(type_): ChunkType) -> bool {
type_[2] & 32 != 0
}
/// Returns true if the chunk is safe to copy if unknown.
pub fn safe_to_copy(ChunkType(type_): ChunkType) -> bool {
type_[3] & 32 != 0
}
impl fmt::Debug for ChunkType {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
struct DebugType([u8; 4]);
impl fmt::Debug for DebugType {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
for &c in &self.0[..] {
write!(f, "{}", char::from(c).escape_debug())?;
}
Ok(())
}
}
f.debug_struct("ChunkType")
.field("type", &DebugType(self.0))
.field("critical", &is_critical(*self))
.field("private", &is_private(*self))
.field("reserved", &reserved_set(*self))
.field("safecopy", &safe_to_copy(*self))
.finish()
}
}
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