Touches 1 à 5 : modifier le nombre de segments
Touches “s” : sauvegarder une image au format png

// P_1_1_2_01
// Generative Gestaltung, ISBN: 978-3-87439-759-9
// First Edition, Hermann Schmidt, Mainz, 2009
// Hartmut Bohnacker, Benedikt Gross, Julia Laub, Claudius Lazzeroni
// Copyright 2009 Hartmut Bohnacker, Benedikt Gross, Julia Laub, Claudius Lazzeroni
//
// http://www.generative-gestaltung.de
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
/**
 * changing the color circle by moving the mouse.
 *      
 * MOUSE
 * position x          : saturation
 * position y          : brighness
 * 
 * KEYS
 * 1-5                 : number of segments
 * s                   : save png
 */

var segmentCount = 360;
var radius = 300;

function setup(){
  createCanvas(710, 710);
  }

function draw(){
  noStroke();
  colorMode(HSB, 360, 100, 100);
  background(0,0,100);
  colorMode(HSB, 360, width, height);
  var angleStep = 360/segmentCount;
  beginShape(TRIANGLE_FAN);
  vertex(width/2, height/2);
  for (var angle=0; angle<=360; angle+=angleStep){
    var vx = width/2 + cos(radians(angle))*radius;
    var vy = height/2 + sin(radians(angle))*radius;
    vertex(vx, vy);
    fill(angle, mouseX, mouseY);
  }
  endShape();

}

function keyTyped(){
  if (key=='s' || key=='S') save("P_1_1_2_01.png");

  switch(key){
  case '1':
    segmentCount = 360;
    break;
  case '2':
    segmentCount = 45;
    break;
  case '3':
    segmentCount = 24;
    break;
  case '4':
    segmentCount = 12;
    break;
  case '5':
    segmentCount = 6;
    break;
  }
}