# NodeBox

Create visual output with Python programming code
Home Download Reference Tutorial Library Gallery About

# photobot.Layer.levels()

## Syntax

    canvas.layers[i].levels()

## Description

Returns a histogram for each RGBA channel. Returns a 4-tuple of lists, r, g, b, and a. Each list has 255 items, a count of pixels found for each value.

## Example

    photobot = ximport("photobot")
    canvas = photobot.canvas(100,100)
    canvas.layer("robot.jpg")
    r, g, b, a = canvas.layers[1].levels()
    print r
    >>>[98, 125, 127, 168, 175, 156, 154, 140, .. ]