how convert image to image 3 bits, 8 colors???

Omnimusha

input_.loadPixels();
for(int r=0;r<58;r++){ 
    for(int x=0 ;x< 58;x++){

        int inputIndex =  x + r * input_.width;
        int rr = (input_.pixels[inputIndex] >> 16) & 240;
        int v = (input_.pixels[inputIndex] >> 8) & 240;
        int b = input_.pixels[inputIndex] & 240;

        input_.pixels[inputIndex] = color(rr, v, b);
    }
}
input_.updatePixels();
image(input_, 0, 0);

asimes

For each pixel:

• Extract red, green, and blue. Each of these will have a value between 0 and 255

• If red is greater than 127 then make it 255. Otherwise make it 0

• Do the same for green and blue. Because each color channel only has two possible values that is 2 * 2 * 2 == 8 colors

On a side note, I am not sure why you are using a bitwise AND of 240 instead of 0xff (which is 255)

quark

& 240 will leave 3 most significant bits

quark

Are you talking about an indexed palette?

koogs

240 is the top 4 bits... 0xF0, you want 0xE0 or 224

but you can do the bitmask of the entire integer in one go by using 0xFFE0E0E0

GoToLoop

https://forum.Processing.org/two/discussion/8045/how-to-format-code-and-text

// forum.processing.org/two/discussion/13986/
// how-convert-image-to-image-3-bits-8-colors

// GoToLoop (2015-Dec-15)

static final byte get3BitColor(color c) {
  color r = c >> 025 & 4;
  color g = c >> 016 & 2;
  color b = c >> 7   & 1;
  return (byte) (r | g | b);
}

void setup() {
  for (int i = 0; i != 10; ++i) {
    color c = (color) random(#000000);
    byte  b = get3BitColor(c);
    println(hex(c, 6), b, binary(b, 3));
  }
  exit();
}

Omnimusha

ok, thanks

input_.loadPixels(); for(int r=0;r<58;r++){ for(int x=0 ;x< 58;x++){

    int inputIndex =  x + r * input_.width;
    int rr = (input_.pixels[inputIndex] >> 16) & 128;
    int v = (input_.pixels[inputIndex] >> 8) & 128;
    int b = input_.pixels[inputIndex] & 128;

    input_.pixels[inputIndex] = color(rr, v, b);
}

} input_.updatePixels(); image(input_, 0, 0);

asimes

That value & 128 was clever, no need for comparison with 127 (greater or less)

Ended up playing around with a bitwise only solution, figured I'd share but it has been a long time since I played with pixels[] so I am not sure if it is any faster than color(r, g, b) (and used to C / C++ bitwise syntax lately, I guess Java does not like logical NOT being used with an int):

void setup() {
  size(100, 100);
  int randomColor = 0xff000000 | (int)random(0xffffff);
  int resultColor = toThreeBitColor(randomColor);
  println(hex(randomColor) + ", " + hex(resultColor));
}

void draw() {
}

void mousePressed() {
  int randomColor = 0xff000000 | (int)random(0xffffff);
  int resultColor = toThreeBitColor(randomColor);
  println(hex(randomColor) + ", " + hex(resultColor));
}

int toThreeBitColor(int randomColor) {
  int r, g, b;

  r = (randomColor >> 16) & 128;
  r = r | (r >> 1);
  r = r | (r >> 2);
  r = r | (r >> 4);

  g = (randomColor >> 8) & 128;
  g = g | (g >> 1);
  g = g | (g >> 2);
  g = g | (g >> 4);

  b = randomColor & 128;
  b = b | (b >> 1);
  b = b | (b >> 2);
  b = b | (b >> 4);

  return 0xff000000 | (r << 16) | (g << 8) | b;
}

Edit: Just realized r, g, and b can be calculated in parallel:

int toThreeBitColor(int randomColor) {
  int rgb;

  rgb = (randomColor & 0x800000) |
        (randomColor & 0x8000) |
        (randomColor & 0x80);

  rgb = rgb | (rgb >> 1);
  rgb = rgb | (rgb >> 2);
  rgb = rgb | (rgb >> 4);

  return 0xff000000 | rgb;
}