Java Compressing an Image using Arrays 2D to 1D? -

i having trouble assignment of mine. have class reads in pgm image files. need create few classes, main 1 being compression class. need compress pgm (represented 2d arrays) 1d array.

here instructions:

public static short[] compress(short[][])  

• is passed 2d array of shorts represents image.
• returns compressed image 1d array of shorts.
• that method main concern.

compression idea:

• look horizontal or vertical runs of pixel values , record number of times pixel value repeated itself.
• note spektre: called rle run length encoding used pcx example

algorithm:

1.compute compressed image array using horizontal runs

2.compute compressed image array using vertical runs

3.choose compress image uses best technique particular image.

4.set header of image

• set first , second values of short [ ] result array width , height values.
• set third value in short[ ] result array 1 horizontal or 2 vertical compression.

5.set image body

• the rest of short [ ] result array filled rle quantity , value

there few other methods

• if wants them:

  public static void write(short[], string)  

• is passed 1d array of shorts represents compressed image , desired filename.

• simply write values text file .compressed extension added filename.

  public static short[] read(string)  

• is passed compressed image filename.

• simply reads values , returns them in 1d array of shorts.

  public static short[][] decompress(short[])  

• is passed 1d array of shorts represents compressed image.

• simply decompress file can display on screen
• using our showgrayimage( ) code have.

thanks in advance!