在Java中获取像素颜色

Question

I know this is an expensive operation and I already tried to use the robot.getPixelColor() function but it works slow, can only calculate like 5 times in a second.

What I'm saying is that 5 times is too small for what I actually want to do, but 20 should be enough. So I ask you if you can suggest me some optimisations to make to my actual code in order to get this result.

My code is:

while (true) {
    color = robot.getPixelColor(x, y);
    red = color.getRed();
    green = color.getGreen();
    blue = color.getBlue();
    // do a few other operations in constant time
}

I don't know if this would help, but x and y don't change inside the while loop. So it's all the time the same pixel coordinates.

Thanks in advance!

EDIT: The pixel color will be taken from a game which will run at the same time with the java program, it will keep changing. The only thing is that are always the same coordinates.

Answer 1

I'm assuming the color is represented as a 32-bit int encoded as ARGB. In that case, instead of calling a method, you could just do bit masking to extract the colors, and that may end up being faster because you don't waste the overhead of calling a method. I'd recommend doing something like this:

int color = robot.getPixelColor(x,y);
int redBitMask = 0x00FF0000;
int greenBitMask = 0x0000FF00;
int blueBitMask = 0x000000FF;
int extractedRed = (color & redBitMask) >> 16;
int extractedGreen = (color & greenBitMask) >> 8;
int extractedBlue = (color & blueBitMask);

Bit shifting and bitwise operations tend to be very fast.