How to save a previous mouse position

Processing Coding Questions
1

Hello
I am having a problem with trying to connect dots ,everytime I click on a position with my mouse I create a dot and what is supposed to happen is that the dots get connected with a line. For this I need to save the previous x and y positions of my dot to connect it to the next dot.But I dont know how to save the previous position. Could anybody help me ?

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int dotX=-10;

int dotY=-10;

int prevDotX;

int prevDotY;

//Executed ONCE, at startup. Setup window size, framerate, etc.:

void setup()

{

size(500,500);

background(0);

}

//Execution LOOP (60 times per second by default):

void draw()

{


}

void drawDot(int size)

{

strokeWeight(size);

stroke(0,255,0);

point(dotX,dotY);

strokeWeight(5);

line(prevDotX,prevDotY,dotX,dotY);


}


//Executed ONLY (but each time) mouse is pressed:

void mousePressed()

{

dotX=mouseX;

dotY=mouseY;

drawDot(10);


}


//Executed ONLY (but each time) a key is pressed:

void keyPressed()

{


}
2

use an ArrayList

How To

Here is an arraylist, you want this before setup()

ArrayList<PVector> listMousePositions = new ArrayList<PVector>();

To add to the arraylist (this could be in the function mousePressed()):

listMousePositions .add(new PVector(mouseX,mouseY));

Read value

PVector pv = listMousePositions.get(2);

display all:

for(PVector pv : listMousePositions ) {

   point (pv.x,pv.y); 

}

OR

for(int i=0; i<listMousePositions.size()-2; ++) {
      PVector pv1 = listMousePositions.get(i); 
      PVector pv2 = listMousePositions.get(i+1); 
      line  (pv1.x,pv1.y,
             pv2.x,pv2.y ); 
}

Set value

listMousePositions.set(int, new PVector(mouseX,mouseY));

(text from the forum)

Chrisir

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