# mouse_button

When a mouse button is pressed, the variable `mouse_button` is set to either `LEFT`, `RIGHT`, or `CENTER`, depending on which button is pressed.

## Examples

<div class="example-table">

<div class="example-row"><div class="example-cell-image">

</div><div class="example-cell-code">

```python
# click within the image and press
# the left and right mouse buttons to
# change the value of the rectangle
def draw():
    if py5.is_mouse_pressed and py5.mouse_button == py5.LEFT:
        py5.fill(0)
    elif py5.is_mouse_pressed and py5.mouse_button == py5.RIGHT:
        py5.fill(255)
    else:
        py5.fill(126)

    py5.rect(25, 25, 50, 50)
```

</div></div>

<div class="example-row"><div class="example-cell-image">

</div><div class="example-cell-code">

```python
# click within the image and press
# the left and right mouse buttons to
# change the value of the rectangle
def draw():
    py5.rect(25, 25, 50, 50)


def mouse_pressed():
    if py5.mouse_button == py5.LEFT:
        py5.fill(0)
    elif py5.mouse_button == py5.RIGHT:
        py5.fill(255)
    else:
        py5.fill(126)
```

</div></div>

</div>

## Description

When a mouse button is pressed, the variable `mouse_button` is set to either `LEFT`, `RIGHT`, or `CENTER`, depending on which button is pressed. (If no button is pressed, `mouse_button` may be reset to `0`. For that reason, it's best to use `mouse_pressed` first to test if any button is being pressed, and only then test the value of `mouse_button`, as shown in the examples.)

Underlying Processing field: [mouseButton](https://processing.org/reference/mouseButton.html)

Updated on December 07, 2024 22:07:08pm UTC