key_code

key_code#

The variable key_code is used to detect special keys such as the arrow keys (UP, DOWN, LEFT, and RIGHT) as well as ALT, CONTROL, and SHIFT.

Examples#

fill_val = 128


def draw():
    py5.fill(fill_val)
    py5.rect(25, 25, 50, 50)


def key_pressed():
    global fill_val
    if py5.key == py5.CODED:
        if py5.key_code == py5.UP:
            fill_val = 255
        elif py5.key_code == py5.DOWN:
            fill_val = 0

    else:
        fill_val = 126

Description#

The variable key_code is used to detect special keys such as the arrow keys (UP, DOWN, LEFT, and RIGHT) as well as ALT, CONTROL, and SHIFT.

When checking for these keys, it can be useful to first check if the key is coded. This is done with the conditional if (key == CODED), as shown in the example.

The keys included in the ASCII specification (BACKSPACE, TAB, ENTER, RETURN, ESC, and DELETE) do not require checking to see if the key is coded; for those keys, you should simply use the key variable directly (and not key_code). If you’re making cross-platform projects, note that the ENTER key is commonly used on PCs and Unix, while the RETURN key is used on Macs. Make sure your program will work on all platforms by checking for both ENTER and RETURN.

For those familiar with Java, the values for UP and DOWN are simply shorter versions of Java’s key_event.VK_UP and key_event.VK_DOWN. Other key_code values can be found in the Java KeyEvent reference.

There are issues with how key_code behaves across different renderers and operating systems. Watch out for unexpected behavior as you switch renderers and operating systems and you are using keys are aren’t mentioned in this reference entry.

If you are using P2D or P3D as your renderer, use the NEWT KeyEvent constants.

Underlying Processing field: keyCode

Updated on March 06, 2023 02:49:26am UTC

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