java - how to extract red, green and blue channels of bitmap in Android -

i have bitmap image loaded memory bitmap object. can load imageview,do operations using canvas , forth.but algorithm i'm using need 3 channel grey scale bitmaps. below image article written eric z goodnight on how geek.the link given below.

https://www.howtogeek.com/howto/42393/rgb-cmyk-alpha-what-are-image-channels-and-what-do-they-mean/

can see in grey scale images corresponding each channels respective colour areas brightest. how can extract grey scale images corresponding each channels bitmap image in android? require 3 bitmaps objects containing these 3 channel grey scales respectively.i have come across method create grey scale setting saturation of colormatrix 0.but returns on 1 grey scale.is there way grey scale images corresponding 3 channels?

a pixel in bitmap format represented 4 bytes integer, describe alpha, red, green , blue channels of pixel. extracting particular channel, can bitwise or on every pixel, appropriate hex value.

for instance, 0xffff0000 represents max alpha (ff), max red (ff), 0 green , 0 blue. bitwise or every pixel, result in green , blue channels ignored, cause 0 (00).

anyway, code might below extracting red channel :

for (int x = 0; x < bitmap.getwidth(); x++)  {     (int y = 0; y < bitmap.getheight(); y++)     {        bitmap.setpixel(x, y, bitmap.getpixel(x, y) & 0xffff0000);    } } 

consequently, green channel can obtained :

 (int x = 0; x < bitmap.getwidth(); x++)  {     (int y = 0; y < bitmap.getheight(); y++)     {        bitmap.setpixel(x, y, bitmap.getpixel(x, y) & 0xff00ff00);    } } 

and blue channel :

for (int x = 0; x < bitmap.getwidth(); x++)  {     (int y = 0; y < bitmap.getheight(); y++)     {        bitmap.setpixel(x, y, bitmap.getpixel(x, y) & 0xff0000ff);    } } 

finally, display image in grayscale can use colormatrix imageview widget :

    colormatrix matrix = new colormatrix();     matrix.setsaturation(0);      colormatrixcolorfilter filter = new colormatrixcolorfilter(matrix);     imageview.setcolorfilter(filter);