Map.

Map.

Use the map() function to take any number and scale it to a new number that is more useful for the project that you are working on. For example, use the numbers from the mouse position to control the size or color of a shape. In this example, the mouse’s x-coordinate (numbers between 0 and 360) are scaled to new numbers to define the color and size of a circle.


void setup() {
  size(640, 360);
  noStroke();
}

void draw() {
  background(0);
  // Scale the mouseX value from 0 to 640 to a range between 0 and 175
  float c = map(mouseX, 0, width, 0, 175);
  // Scale the mouseX value from 0 to 640 to a range between 40 and 300
  float d = map(mouseX, 0, width, 40, 300);
  fill(255, c, 0);
  ellipse(width/2, height/2, d, d);   
}

Functions Used

fill()

Sets the color used to fill shapes

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size()

Defines the dimension of the display window width and height in units of pixels

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ellipse()

Draws an ellipse (oval) to the screen

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setup()

The setup() function is run once, when the program starts

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map()

Re-maps a number from one range to another

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draw()

Called directly after setup(), the draw() function continuously executes the lines of code contained inside its block until the program is stopped or noLoop() is called

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noStroke()

Disables drawing the stroke (outline)

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background()

The background() function sets the color used for the background of the Processing window

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