Im making a simple drawing app and I want to add some features but don't know how.

djamboo

I'd like to add a feature to increase the brush size with the up and down arrows (im using ellipse's), and also make a feature where I can click a triangle which ive made already to change the shape of the brush. Ive tried but cant figure it out. Any help would be appreciated.

Chrisir

It wouldn't be easier if you show your code or your attempt.

1.

Now for cursor use a function keyPressed () :

void keyPressed () {

    // See reference for keyPressed 

    if(keyCode==UP) {

         diameter++;

    } 

    else if(keyCode==DOWN) {

         diameter--;

    }

} // function 

use the float variable diameter in your ellipse command (your brush size)

2.

Triangle

When the three corners of the triangle are stored in a database or you know them as variables or numbers in your code you can calculate the middle of the triangle by adding the three X values and divide by 3 and repeat for y values.

float middleTriangleX = ( x1 + x2 + x3 ) / 3.0; 

Then use dist() to calculate if the mouse is inside the triangle:

See reference for dist() :

if(dist(mouseX, mouseY, middleTriangleX, middleTriangleY) < 50) {
      //inside 
}

I only show the principle here you have to write it yourself. Especially declaring variables.

Chrisir ;-)

[EDITED]

jeremydouglass

@djamboo --see keyCode in the references:

• https://processing.org/reference/keyCode.html

How to change a variable with UP / DOWN:

int x;

void draw(){
  background(0);
  text(x,width/2,height/2);
}

void keyPressed(){
  if(keyCode==UP){
    x = x+1;
  }
  if(keyCode==DOWN){
    x = x-1;
  }
}