Hello dear users,

I'm actually coding a little program with processing.

My problem is, that I have a color-bar. I choose some color out of this bar with my left mouse button.

This value is saved in a variable of the "color" type with this function:

Code:

color value = get(mouseX, mouseY); 

Now I'm able to make an output of this selected hex-value:

Code:

println("Original Hex Value: " + hex(value));  

gives this back: Original Hex Value: FF4700FF

I don't really know, why i go 8 characters back, because the important value is just "4700FF". THIS is the hex value of the color i selected.

Now I try to describe what I want to do with this value.

For example:
Original Hex Value: #4700FF

I want to "modify" this value with some kind of "right rotation".

The first modified value should look this this: #FF4700 and the second one #00FF47.

I need this operations to get a "Triadic Color Harmony" but I'm not able to do this "rotation step".

I tried already the following things:

1. I made a new variable of String type:  
Code:

String hex = "#"+hex(value,6); 

2. Made a new String out of the the original value:
Code:

String rotatedHex = hex.substring(5) + hex.substring(1,5); 

3. Did a String to Integer convert:
Code:

komp_wert1 = (Integer.valueOf(rotatedHex,16).intValue()); 

4. Some println():
Code:

  println("Original Hex: " + hex(value)); 
  println("OriginalHex as String: " + hex); 
  println("Rotierted  Hex: " + rotatedHex); 

5. Terminal output:
Code:

Original Hex: FFB700FF
Original Hex as String: #B700FF
Rotierted Hex: FFB700 

Can anybody bring me a little light to solve this problem?

Thanks in advance!
Mike

Mike85 wrote on Jan 4^th, 2010, 7:43am:


The first two characters represent the alpha value of the colour; where FF = fully opaque and 00 = fully transparent.

antiplastik - just thinking aloud, but does this really require string manipulation?  I'm thinking it could be done with bitwise operators; though actually I suppose string manipulation might be simpler

blindfish wrote on Jan 4^th, 2010, 8:25am:


No doubt about it! That's what I meant when I said "Looks ugly, but works."  

I was just about to suggest unhex but my test isn't doing what I expect:

Code:

String s = "00FF00";

void setup() {
  size(100,100);
  // background should be #ff0000 = red
  background(shiftLeft(s));

  // rect should be #0000ff = blue, but it looks like it ignores the leading zeros and returns #ff
  fill(shiftRight(s));
  rect(25,25,50,50);
  
} 


color shiftLeft(String s) {
  color c = unhex(s.substring(2, 6) + s.substring(0, 2));
  return c;
}

color shiftRight(String s) {
  color c = unhex(s.substring(4, 6) + s.substring(0, 4));
  return c;
} 

It appears to be ignoring leading zeros when converting to the int, which doesn't seem right...  Unless of course I've done something wrong

I'm not allowed to post hyperlinks in this forum, because I have < 5 postings at the moment -.-!

Here is the latest version of my program:

hxxp://campus.fh-worms.de/~inf456/applet/index.html

(I have to substitute http ---> hxxp to post this link).

Just klick within the color-bar and you see the effect