Need conversion mechanism for converting 24 bit image to 16 bit

Question

In my java project I need to convert 24 bit image to 16 bit image. I don't have any clue. Please provide me the option to implement it.
Thanks,
jai

Answer 1

That doesn't tell me much, and I know what you're talking about. I doubt that it tells the OP anything useful whatsoever.Sorry EJP, it was a mouthful I know. Maybe this will help instead, a ColorConversionOps class to work on *32 bit > 16 bit > 32 bit colors*. To help clarify where the 16 bit color input and output goes, some of the methods return or require parameters of type short. Also take notice the bitmask for variables of type short vs the bitmasks for int. AND pay particular attention to the unsigned right bit-shifting of the most-significant-digit.
public class ColorConversionOps
  public static short convert32_16(int rgb) {
    int a = ((rgb & 0xF0000000) >>> 16);
    int r = ((rgb & 0x00F00000) >>  12);
    int g = ((rgb & 0x0000F000) >>   8);
    int b = ((rgb & 0x000000F0) >>   4);
    return (short)( a | r | g | b);
  public static int convert16_32(short rgb) {
    int a = ((rgb & 0xF000) << 16);
    int r = ((rgb & 0x0F00) << 12);
    int g = ((rgb & 0x00F0) <<  8);
    int b = ((rgb & 0x000F) <<  4);
    return (a | r | g | b);
  public static void printRGB_32(int rgb) {
    System.out.println("a="+((rgb & 0xFF000000) >>> 24));
    System.out.println("r="+((rgb & 0x00FF0000) >>  16));
    System.out.println("g="+((rgb & 0x0000FF00) >>  8));
    System.out.println("b="+ (rgb & 0x000000FF));
    System.out.println();
  public static void printRGB_16(short rgb) {
    System.out.println("a="+((rgb & 0xF000) >>> 12));
    System.out.println("r="+((rgb & 0x0F00) >>  8));
    System.out.println("g="+((rgb & 0x00F0) >>  4));
    System.out.println("b="+ (rgb & 0x000F));
    System.out.println();
}Now to make the conversion from 32 bit color to 16 bit color and back. NOTICE there willl be a loss of precision -- just like someone else has already said.
public class Test
  public static void main(String[] args)
    int rgb = 0xFFFFFFFF;
    ColorConversionOps.printRGB_32(rgb);
    //a=255
    //r=255
    //g=255
    //b=255
    rgb = ColorConversionOps.convert32_16(rgb);
    ColorConversionOps.printRGB_16((short)rgb);
    //a=15
    //r=15
    //g=15
    //b=15
    rgb = ColorConversionOps.convert16_32((short)rgb);
    ColorConversionOps.printRGB_32(rgb);
    //a=240
    //r=240
    //g=240
    //b=240
}And now we see, the reason 16bit color is so unpopular to the rest of the world, but not for us here!