java - JH Labs Quantize Usage to reduce image color depth -

i trying use quantizefilter in

http://www.jhlabs.com/ip/filters/index.html

to reduce color depth of screen shot.

here very simple code:

    robot robo = new robot();     bufferedimage notquantized = robo.createscreencapture( new rectangle ( 0, 0, 300, 300 ) );     bufferedimage quantized = new bufferedimage( 300, 300, bufferedimage.type_int_bgr);     file nonquantized = new file ("c:\\nonquantized.png");     file quantized = new file("c:\\quantized.png");     nonquantized.createnewfile();     quantized.createnewfile();     quantizefilter bla = new quantizefilter();      int [] outpixels = new int[300*300*3];     int [] inpixels = new int[300*300*3];      notquantized.getraster().getpixels( 0, 0, 300, 300, inpixels );     bla.quantize( inpixels, outpixels, 300, 300,2, true, true );      quantized.getraster().setpixels( 0, 0, 300, 300, outpixels );     imageio.write( quantized, "png", quantized );     imageio.write( notquantized, "png", nonquantized ); 

however, left is:

original img:

quantized img:

a further analysis of problem shows inpixels array filled incorrectly; filled 3 times upper one-third of original image.

any pointers how can fix that?

additionally, links + fast quantization algorithm in java? search algorithm take type_int_bgr image , produce new type_int_bgr image less actual difference in pixels, deflated.

for example, if have 2 pixels in original image, values 255, 255, 234 , 1 value 255, 255, 236, should both converted 255,255,240. cheers

the following example convert image correctly:

quantizefilter q = new quantizefilter(); int [] inpixels = new int[image.getwidth()*image.getheight()*3]; int [] outpixels = new int[image.getwidth()*image.getheight()*3]; image.getraster().getpixels( 0, 0, image.getwidth(), image.getheight(), inpixels ); q.quantize(inpixels, outpixels, image.getwidth(), image.getheight(), 64, false, false); writableraster raster = (writableraster) image.getdata(); raster.setpixels(0,0,width,height,outpixels); 

also there no reason create files implicitly, imageio.write creates them automatically.