Pen tool & Area Calculation

robinzon

Hi everyone,

I wonder if there is a way to draw a custom shape by picking points from the mouse (Like "Pen Tool" in photoshop and Illustrator) and then calculating the are of that shape? Thanks...

Ater

Hey. Try this to create a pen-like tool (sorry for the formatting). Getting the area of the shape is harder and out of my competence though.

var prevPosX;
var prevPosY;

function setup() {
createCanvas(500,500);
background(0);
stroke(255);
}

function draw() {
}

function mousePressed() {
  if (prevPosX !=0 && prevPosY !=0) {
     line(prevPosX, prevPosY, mouseX, mouseY);
}
     prevPosX = mouseX;
     prevPosY = mouseY;
     return false;
    }

knockout

I haven't tried coding but since processing can track the x and y coordinates, you can probably make a code base on the algorithms of finding the area irregular polygon :

https://www.mathsisfun.com/geometry/area-irregular-polygons.html

I am thinking you will probably need to set a counter with mouse pressed(for the vertices) and using a for loop that will go through the calculation and that should work