pick one of x number of colors randomly

joySeeing

I have 5 colors defined as colors and I want to pick one of them randomly. Although I thought this was simple it doesn't seem so (unless it really is...?). I defined the 5 colors. I tried storing them in an array list, randomly picking a number between 1-5 and then use that to get the index of the array list. Probably is... "color" isn't a type although it is constructed like a type (int, float, etc.). color myColor = color(255, 120, 5);

I've tried putting them in hashmaps which worked well and was making a function to get them out only you can't "return" a color from a function. color (or Color) getRandomColor() (for example) doesn't work.

Any suggestions for this simple exercise?

TfGuy44

What's wrong with a plain old array?

color[] colors = { 
  color(255), 
  color(255, 0, 0), 
  color(255, 255, 0), 
  color(0, 255, 0), 
  color(0, 0, 255)
};
int index;

void setup() {
  size(200, 200);
  pick();
}

void pick() {
  index = int(random(colors.length));
}

void draw() {
  background(colors[index]);
}

void mousePressed() {
  pick();
}

joySeeing

Thanks! I suppose after doing more research that "color" is a primitive and not a class and therefore cannot be stored in an ArrayList?

Arrays, arraylists, lists, linkedlists + many others I'm sure. Still getting used to it...!

GoToLoop

color is alias for int primitive datatype:
https://Processing.org/reference/color_datatype.html
https://Processing.org/reference/int.html

Java's Collection containers can't store primitive datatypes though!
For that we gotta use a primitive's corresponding wrapper class instead.

For color & int, it is Integer:
http://docs.Oracle.com/javase/8/docs/api/java/lang/Integer.html
http://docs.Oracle.com/javase/8/docs/api/java/lang/Number.html

BtW, Processing 2 series offers alternative classes for ArrayList<Integer>, ArrayList<Float> &
ArrayList<String>. All backed up w/ real primitives! Check them out:
https://processing.org/reference/IntList.html
https://processing.org/reference/FloatList.html
https://processing.org/reference/StringList.html (Not primitive of course! :P)

joySeeing

Thanks for the info. Here's another quick question related. What if I want to store a random color in an evictingqueue (data structure of n size that take out the nth object when adding a new one). I think it is derived from a collection. http://docs.guava-libraries.googlecode.com/git/javadoc/com/google/common/collect/EvictingQueue.html

You can't do EvictingQueue'<color'>, for instance. (without the ' ' )

So I made my own class:

class RandomColor {
  int r, g, b;
  
  RandomColor() {
    colorMode(RGB, 255);
    r = int(random(255));
    g = int(random(255));
    b = int(random(255));
  }
  
  int getR() {
    return r;  
  }

  int getG() {
    return g;  
  }
  
  int getB() {
    return b;  
  }
  // this is too complicated, how do you make it like {r, g, b} http://toxiclibs.org/docs/core/toxi/geom/Vec3D.html which extends object()... what is this.
}

and then I can at least use EvictingQueue'<RandomColor'>. (without the ' ')

All I really want to store is something like {r, g, b} like Toxi's Vec3D, an object I guess. In java, this isn't obvious though.

The complexitiy might be hendering my performance too. 100 of these random colors in an evicting queue drawing circles at 200 points on the screen = 20,000 circles per frame. Maybe that goes slow anyways...

GoToLoop

• I've already explained in my reply that in general containers don't accept primitive datatypes!
• Some do of course, like Processing's IntList. But don't expect that for most cases!
• Already told ya the corresponding object class wrapper for int, and consequently its alias color, is Integer.
• Also Consider Java's ArrayDeque in place of Guava's EvictingQueue. We don't have that installed!
• Please re-read my 1st reply! :-\"