alpha()

Extracts the alpha value from a color, scaled to match current color_mode().

Examples

def setup():
    py5.no_stroke()
    c = py5.color(0, 126, 255, 102)
    py5.fill(c)
    py5.rect(15, 15, 35, 70)
    value = py5.alpha(c)  # sets 'value' to 102
    py5.fill(value)
    py5.rect(50, 15, 35, 70)

Description

Extracts the alpha value from a color, scaled to match current color_mode().

The alpha() function is easy to use and understand, but it is slower than a technique called bit shifting. When working in color_mode(RGB, 255), you can achieve the same results as alpha() but with greater speed by using the right shift operator (>>) with a bit mask. For example, alpha(c) and c >> 24 & 0xFF both extract the alpha value from a color variable c but the later is faster.

This method has additional color functionality that is not reflected in the method’s signatures. For example, you can pass the name of a color (e.g. “green”, “mediumpurple”, etc). Look at the online “All About Colors” Python Ecosystem Integration tutorial for more information.

Underlying Processing method: alpha

Signatures

alpha(
    rgb: int,  # any value of the color datatype
    /,
) -> float

Updated on December 25, 2023 16:36:33pm UTC