Mouse Inputs in Processing

1
Mouse Inputs in Processing
2
Interacting with the Mouse

• mouseX and mouseY pg 205-211
• The position of the mouse in the canvas
• pmouseX and pmouseY pg 208
• The previous position of the mouse (in the last
  frame)
• mouseButton pg 212-213
• Which mouse button has pressed
• mousePressed pg 212-213
• true if the mouse button is pressed, false
  otherwise
• mousePressed() pg 229-231
• Function that runs when the mouse is pressed

3
Hello Mouse

• void setup()
• size(400, 400)
• stroke(255)
• void draw()
• // try moving background() to setup()
• background(192, 64, 200)
• // mouseX is a variable that stores the
  horizontal position
• // of the mouse.
• // mouseY is a variable that stores the
  vertical position
• // of the mouse.
• line(150, 25, mouseX, mouseY)

4
Moving with the Mouse

• // Circle follows the cursor
• void setup()
• size(100, 100)
• smooth()
• noStroke()
• void draw()
• background(126)
• ellipse(mouseX, mouseY, 33, 33)

5
Highlighting with the Mouse

• // Cursor position selects a quadrant of the
  display window
• void setup()
• size(100, 100)
• noStroke()
• fill(0)
• void draw()
• background(204)
• if ((mouseX lt 50) (mouseY lt 50))
• rect(0, 0, 50, 50) // Upper-left
• else if ((mouseX lt 50) (mouseY gt 50))
• rect(0, 50, 50, 50) // Lower-left
• else if ((mouseX gt 50) (mouseY lt 50))
• rect(50, 0, 50, 50) // Upper-right
• else
• rect(50, 50, 50, 50) // Lower-right

6
pmouse

• // Draw a line between the current and previous
  positions
• void setup()
• size(100, 100)
• strokeWeight(8)
• smooth()
• void draw()
• background(204)
• // pmouseX is a variable that stores the
  horizontal position
• // of the mouse in the previous frame.
• // pmouseY is a variable that stores the vertical
  position of
• // the mouse in the previous frame.
• line(mouseX, mouseY, pmouseX, pmouseY)

7
mousePressed and mouseButton

• Like mouseX and mouseY, mousePressed is a
  property of the mouse (a variable), but it is of
  type boolean.
• The mousePressed variable stores true if any
  mouse button is pressed, and false otherwise. It
  reverts to false as soon as the button is
  released.
• The mouseButton variable is LEFT, CENTER, or
  RIGHT depending on the mouse button most recently
  pressed.
• mouseButton retains its value until a different
  mouse button is pressed

8
A Simple Paint Example

• int brushSize 20
• void setup()
• size(400, 400)
• smooth()
• noStroke()
• background(255)
• void draw()
• if (mousePressed)
• brush(mouseX, mouseY)
• void brush(int x, int y)
• fill(CC3300)
• // note the color is specified as a
  hexadecimal number
• arc(x, y, brushSize, brushSize, 0, PI)
• fill(003333)

9
mousePressed()

• We can try to get the same functionality by using
  the mousePressed() event instead of the
  mousePressed variable.
• To use event, we need to write a function by the
  same name in our sketch, and it will be called
  automatically every time the event occurs. In the
  following code, mousePressed() will be called
  every time the mouse is pressed.

10

• int brushSize 20
• void setup()
• size(400, 400)
• smooth()
• noStroke()
• background(255)
• void draw() // keep the motor running
• void mousePressed()
• brush(mouseX, mouseY)
• void brush(int x, int y)
• fill(CC3300)
• arc(x, y, brushSize, brushSize, 0, PI)
• fill(003333)

11
mousePressed vs. mousePressed()

• You'll notice that the program does not behave
  the same way. Although the mousePressed variable
  and the mousePressed() event have the same name,
  they represent different things
• mousePressed is true for as long as the mouse
  button is down, whereas mousePressed() is called
  once whenever the mouse becomes pressed, i.e.
  once per click.