I have upgraded the code of my sketch from the 069 version.
But it seems that the new one works more slowly.
Is it something wrong in the syntax?
Thank you for advice..

int MAX_array =1000;
int max_pix_amount = 0;
int pix_amount =0;
pix[] pix_fountain = new pix[MAX_array];
void setup() {
 size(400,400);
 framerate(30);
 for (int i = 0; i < MAX_array; i++) {
   float gray = random(255);
   pix_fountain[i] = new pix (gray,0,0,random(1,5),random(1,4));
 }
}

void draw() {
 background(255);
 pix_amount = mouseX/10;
 if (max_pix_amount < MAX_array){
   max_pix_amount += pix_amount;
 }
 if (max_pix_amount > MAX_array){
   max_pix_amount = MAX_array;
 }
 for (int i = 0; i < max_pix_amount; i++) {
   pix_fountain[i].spray();
   pix_fountain[i].check_lost();
 }
}

class pix
{
 float g;
 float xpos;
 float ypos;
 float xvel;
 float yvel;
 pix(float g_, float xp, float yp, float xv,float yv) {
   g = g_;
   xpos = xp;
   ypos = yp;
   xvel = xv;
   yvel = yv;
 }

 void spray () {
   xpos = xpos + (((mouseX/10)* xvel)/10);
   ypos = ypos + (((mouseX/10) *yvel)/10);
   point(xpos,ypos);
 }
 void check_lost () {
   if (xpos > width || ypos > height){
     xpos = 0;
   ypos = 0;}
}
}