Example

example_4_3

// Learning Processing
// Daniel Shiffman
// http://www.learningprocessing.com

// Example 4-3: Varying variables

// Declare and initialize two integer variables at the top of the code.
int circleX = 0;
int circleY = 100;

void setup() {
  size(200,200);
  smooth();
}

void draw() {
  background(255);
  stroke(0);
  fill(175);
  // Use the variables to specify the location of an ellipse.
  ellipse(circleX,circleY,50,50);
  
  // An assignment operation that increments the value of circleX by 1.
  circleX = circleX + 1;
}

3 Comments
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  1. so what is the solution to varying the speed at which the circle grows? I wound up using the abs() call as it was in the previous chapter.

    Comment by Gabe — October 17, 2009 @ 11:31 pm

  2. In this case, you just want to define a variable for the size of the circle, instead of hardcoding the number 50 in, i.e.

    int circleW = 100;
int circleH = 100;

    Then you use those variables when drawing the circle.

      ellipse(circleX,circleY,circleW,circleH);

    And then adjust the values however you like!

      circleW = circleW + 1;  // Growing
  circleH = circleH - 1;  // Shrinking

    Comment by admin — October 18, 2009 @ 8:49 am

  3. Thanks. I’m sure I’ll have more questions in the hover chapters…:)

    Comment by Gabe — October 18, 2009 @ 10:42 am

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