Package org.apache.pdfbox.pdmodel.graphics.predictor

Class Average

java.lang.Object
org.apache.pdfbox.pdmodel.graphics.predictor.PredictorAlgorithm
org.apache.pdfbox.pdmodel.graphics.predictor.Average
public class Average extends PredictorAlgorithm
We can use raw on the right hand side of the decoding formula because it is already decoded. average(i,j) = raw(i,j) + (raw(i-1,j)+raw(i,j-1)/2 decoding raw(i,j) = avarage(i,j) - (raw(i-1,j)+raw(i,j-1)/2
Version:
$Revision: 1.3 $
Author:
xylifyx@yahoo.co.uk

  • Constructor Details

    • Average

      public Average()

  • Method Details

    • encodeLine

      public void encodeLine(byte[] src, byte[] dest, int srcDy, int srcOffset, int destDy, int destOffset)
      Not an optimal version, but close to the def. encode line of pixel data in src from srcOffset and width*bpp bytes forward, put the decoded bytes into dest.
      Specified by:
      encodeLine in class PredictorAlgorithm
      Parameters:
      src - raw image data
      dest - encoded data
      srcDy - byte offset between lines
      srcOffset - beginning of line data
      destDy - byte offset between lines
      destOffset - beginning of line data

    • decodeLine

      public void decodeLine(byte[] src, byte[] dest, int srcDy, int srcOffset, int destDy, int destOffset)
      decode line of pixel data in src from src_offset and width*bpp bytes forward, put the decoded bytes into dest.
      Specified by:
      decodeLine in class PredictorAlgorithm
      Parameters:
      src - encoded image data
      dest - raw data
      srcDy - byte offset between lines
      srcOffset - beginning of line data
      destDy - byte offset between lines
      destOffset - beginning of line data