struct PNG::Scanline

• PNG::Scanline
• Struct
• Value
• Object

Overview

A row of pixels including their filtering method

Defined in:

Constructors

• .new(header : PNG::Header, filter : PNG::FilterMethod, data : Slice(UInt8))

Instance Method Summary

• #[](*args, **options)
• #[](*args, **options, &)
• #[]?(*args, **options)
• #[]?(*args, **options, &)
• #average(other : Scanline, &block : UInt8 -> Nil)

  Filt(x) = Orig(x) - floor((Orig(a) + Orig(b)) / 2)

• #average(other : Nil, &block : UInt8 -> Nil)

  Filt(x) = Orig(x) - floor((Orig(a) + Orig(b)) / 2)

• #average(other : Scanline | Nil, io : IO)

  Filt(x) = Orig(x) - floor((Orig(a) + Orig(b)) / 2)

• #bit_depth(*args, **options)
• #bit_depth(*args, **options, &)
• #bits_per_pixel(*args, **options)
• #bits_per_pixel(*args, **options, &)
• #bytes_per_pixel(*args, **options)
• #bytes_per_pixel(*args, **options, &)
• #channels(*args, **options)
• #channels(*args, **options, &)
• #data : Bytes
• #data=(data : Bytes)
• #filter : FilterMethod
• #filter(previous : Scanline | Nil, &block : UInt8 -> Nil)

  Apply a filter

• #filter=(filter : FilterMethod)
• #header : Header
• #header=(header : Header)
• #none(&)

• #paeth(other : Scanline, &block : UInt8 -> Nil)

  Filt(x) = Orig(x) - PaethPredictor(Orig(a), Orig(b), Orig(c))

• #paeth(other : Nil, &block : UInt8 -> Nil)

  Filt(x) = Orig(x) - PaethPredictor(Orig(a), Orig(b), Orig(c))

• #paeth(other : Scanline | Nil, io : IO)

  Filt(x) = Orig(x) - PaethPredictor(Orig(a), Orig(b), Orig(c))

• #paeth_predict(a, b, c)

  https://www.w3.org/TR/png-3/#bib-paeth

• #pixel(x : Int) : Indexable(UInt8)

  Return the bytes that represent a pixel at x in this scanline

• #set_pixel(x : Int, values : Indexable(UInt8)) : Nil

  Sets a pixel in this scanline based on the header

• #sub(&block : UInt8 -> Nil)

  Filt(x) = Orig(x) - Orig(a) Run the sub filter strategy yielding each modified byte to the block

• #sub(io : IO)

  Filt(x) = Orig(x) - Orig(a) Run the sub filter strategy yielding each modified byte to the block

• #unaverage(other : Scanline)

  Removes the type 3 Average filter via: Recon(x) = Filt(x) + floor((Recon(a) + Recon(b)) / 2)

• #unaverage(other : Nil)

  Removes the type 3 Average filter via: Recon(x) = Filt(x) + floor((Recon(a) + Recon(b)) / 2)

• #unfilter(previous : Scanline | Nil)

  Remove any filtering in this scanline @see https://www.w3.org/TR/png-3/#9Filters

• #unpaeth(other : Scanline)

  Remove the Paeth filter type Recon(x) = Filt(x) + PaethPredictor(Recon(a), Recon(b), Recon(c))

• #unpaeth(other : Nil)

  Remove the Paeth filter type Recon(x) = Filt(x) + PaethPredictor(Recon(a), Recon(b), Recon(c))

• #unsub

  Remove the sub filter Recon(x) = Filt(x) + Recon(a)

• #unup(other : Scanline | Nil)

  Remove the up filter

• #up(other : Scanline, &block : UInt8 -> Nil)

  Filt(x) = Orig(x) - Orig(b)

• #up(other : Nil, &block : UInt8 -> Nil)

  Filt(x) = Orig(x) - Orig(b)

• #up(other : Scanline | Nil, io : IO)

  Filt(x) = Orig(x) - Orig(b)

Constructor Detail

Instance Method Detail