[Processing] Transformation example in Processing

2D Transformations example:Online Demo

//@ http://scriptdemo.blogspot.com/ int numP; myrose[] roses; float rotAngle, myscale; float shiftX, shiftY; void setup() {   size(500,500);   numP=36;   smooth();   roses=new myrose[numP];   myscale=1;   rotAngle=0;   shiftX=width/2;   shiftY=height/2;   frameRate(30);   for (int n=0; n<numP; n++)   {     roses[n]=new myrose();   }   noStroke(); } void draw() {   background(255);   translate(shiftX,shiftY);   if (!mousePressed)   {     rotAngle=rotAngle+PI/100;   }   rotate(rotAngle);   scale(myscale);   pushMatrix();   for (int n=0; n<numP; n++)   {    roses[n].myrose();    roses[n].setangle(n*TWO_PI/numP);    roses[n].showit();   }   popMatrix(); } class myrose {   float myangle;   int nres=20;   float[] xx=new float[nres*2+1];   float[] yy=new float[nres*2+1];   float rr=0.4*width;   float rr05=rr/2;   float rry=0.1*rr;   void myrose()   {      for (int n=-nres; n<=nres; n++)      {         xx[n+nres]=rr05+n*rr05/nres;         yy[n+nres]=rry*sin(n*TWO_PI/nres);      }   }   void showit()   {     pushMatrix();     rotate(myangle);     for (int n=0; n<xx.length; n++)     {       fill(n*255/xx.length,127);       ellipse(xx[n],yy[n],5,5);     }     popMatrix();   }   void setangle(float ang)   {     myangle=ang;   } } void mouseDragged() {   if (mouseButton==CENTER)   {     shiftX+=(mouseX-pmouseX);     shiftY+=(mouseY-pmouseY);   } else if (mouseButton==LEFT) {     float d0=(pmouseX-width/2)*(pmouseX-width/2)+(pmouseY-height/2)*(pmouseY-height/2);     float dc=(mouseX-width/2)*(mouseX-width/2)+(mouseY-height/2)*(mouseY-height/2);     myscale=(sqrt(dc)-sqrt(d0));   } }