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// Package png implements some of the PNG format using Restruct.
package png
// ColorType is used to specify the color format of a PNG.
type ColorType byte
// Enumeration of valid ColorTypes.
const (
ColorGreyscale ColorType = 0
ColorTrueColor ColorType = 2
ColorIndexed ColorType = 3
ColorGreyscaleAlpha ColorType = 4
ColorTrueColorAlpha ColorType = 6
)
// File contains the data of an image.
type File struct {
Magic [8]byte
Header Chunk
Chunks []Chunk `struct-while:"!_eof"`
}
// Chunk contains the data of a single chunk.
type Chunk struct {
Len uint32
Type string `struct:"[4]byte"`
Data struct {
IHDR *ChunkIHDR `struct-case:"$'IHDR'" json:",omitempty"`
IDAT *ChunkIDAT `struct-case:"$'IDAT'" json:",omitempty"`
IEND *ChunkIEND `struct-case:"$'IEND'" json:",omitempty"`
Raw *ChunkRaw `struct:"default" json:",omitempty"`
} `struct-switch:"Type"`
CRC uint32
}
// ChunkIHDR contains the body of a IHDR chunk.
type ChunkIHDR struct {
Width uint32
Height uint32
BitDepth byte
ColorType ColorType
CompressionMethod byte
FilterMethod byte
InterlaceMethod byte
}
// ChunkIDAT contains the body of a IDAT chunk.
type ChunkIDAT struct {
Parent *Chunk `struct:"parent" json:"-"`
Data []byte `struct-size:"Parent.Len"`
}
// ChunkRaw contains the body of an unrecognized chunk.
type ChunkRaw struct {
Parent *Chunk `struct:"parent" json:"-"`
Data []byte `struct-size:"Parent.Len"`
}
// ChunkIEND contains the body of a IEND chunk.
type ChunkIEND struct {
}
// ChunkPLTE contains the body of a PLTE chunk.
type ChunkPLTE struct {
}
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