Module: ZIMG::PNG::Scanline::Mixins::Interlaced

Defined in:
lib/zimg/png/scanline_mixins.rb

Overview

scanline decoding

Instance Method Summary collapse

Instance Method Details

#prev_scanline_byte(x) ⇒ Object 



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# File 'lib/zimg/png/scanline_mixins.rb', line 10

def prev_scanline_byte(x)
  # When the image is interlaced, each pass of the interlace pattern is
  # treated as an independent image for filtering purposes
  image.adam7.pass_start?(@idx) ? 0 : image.scanlines[@idx - 1].decoded_bytes.getbyte(x)
end