A number of plotdevice commands can take lists of numeric arguments to specify a color (see stroke(), fill(), background(), etc.). When called with keyword arguments alone, The color() command allows you to control how these numbers should be interpreted in subsequent color-modification commands.

By default, color commands interpret groups of 3 or more numbers as r/g/b triplets (with an optional, final alpha arg). If the mode keyword arg is set to RGB, HSV, or CMYK, subsequent color commands will interpret numerical arguments according to that colorspace instead.

The range keyword arg sets the maximum value for color channels. By default this is 1.0, but 255 and 100 are also sensible choices.

For instance here are three equivalent ways of setting the fill color to ‘blue’:

color(mode=HSV)
fill(.666, 1.0, .76)
color(mode=RGB, range=255)
fill(0, 0, 190)
color(mode=CMYK, range=100)
fill(95, 89, 0, 0)

Color mode & range changes can be constrained to a block of code using the with statement. e.g.,

background(.5, .5, .6) # interpteted as r/g/b (the default)
with color(mode=CMYK): # temporarily change the mode:
    stroke(1, 0, 0, 0) # - interpteted as c/m/y/k
fill(1, 0, 0)          # outside the block, the mode is restored to r/g/b

Making Colors

When called with a sequence of color-channel values, color() will return a reusable Color object. These can be passed to color-related commands in lieu of numeric args. For example:

red = color(1, 0, 0)                   # r/g/b
glossy_black = color(15, 15, 15, 0.25) # r/g/b/a
background(red)
fill(glossy_black)

You can also prefix the numeric args with a color mode as a convenience for setting one-off colors in a mode different from the current colorspace:

color(mode=HSV)                        # set mode to h/s/b
hsb_color = color(.7, 1, .8)           # uses current mode (h/s/b)
cmyk_color = color(CMYK, 0, .7, .9, 0) # interpreted as c/m/y/k
still_hsb = color(1, .5, .25)          # uses current mode (h/s/b)

Greyscale colors can be created regardless of the current mode by passing only one or two values (for the brightness and alpha respectively):

fill(1, .75) # translucent white
stroke(0)    # opaque black

If you pass a string to a color command, it must either be a hex-string (beginning with a #) or a valid CSS color-name. The string can be followed by an optional alpha argument:

background('#f00')   # blindingly red
fill('#74e9ff', 0.4) # translucent pale blue
stroke('chartreuse') # electric bile

fill(r, g, b, a=1.0)
fill(h, s, v, a=1.0)
fill(c, m, y, k, a=1.0)
fill(v, a=1.0)
fill(color)
fill(*colors, angle, steps=[0,1]) # axial gradient
fill(*colors, steps=[0,1], center=[0,0]) # radial gradient

Sets the current fill color, interpeting the arguments according to the canvas’s current color-mode and range. For details see the color() command.

If more than one color arg is included, a gradient will be drawn. Pass a list with the steps keyword arg to set the relative location of each color in the gradient (0-1.0). The relative locations are based on the bounding-box of the object being filled (not its convex hull). So for highly rounded objects, you’ll need to adjust the steps to account for the dead-space in the corners of the bounds.

Including an angle keyword arg will draw a linear gradient at that orientation (otherwise it will be radial). Radial gradients will draw from the object center by default, but a relative center can be specified with the center keyword arg. If included, the center arg should be a 2-tuple with x,y values in the range -1 to +1.

In addition to colors, you can also call fill() with an image() as its sole argument. In this case the image will be tiled to fit the object being filled.

pen(nib, join=MITER, cap=BUTT, dash=None)

Sets the line-style to be used when a stroke() color has been set. The nib argument sets the width of the stroke in terms of the units set in size() (points by default). The cap argument controls how endpoints of beziers are drawn: BUTT, SQUARE, or ROUND. Vertices within a bezier are controled by the join arg and can be set to MITER, ROUND, or BEVEL.

If the dash argument is not None, it must be either a single number or a list of them specifying on-off intervals for drawing a dashed line

a context manager allowing pen changes to be constrained to the block of code following a with statement.

stroke(r, g, b, a=1.0)
stroke(h, s, v, a=1.0)
stroke(c, m, y, k, a=1.0)
stroke(v, a=1.0)
stroke(color)

Sets the stroke color used when drawing lines around shapes, paths, and text. All drawing operations following a call to stroke() will be outlined in the specified color (with a ‘nib’ width set via the pen() command).

The color is specified in terms of RGB, HSV or CMYK depending on the canvas’s current color-mode and range. For details see the color() command. To disable stroke-drawing either call stroke() with None or use the nostroke() convenience method.