campy.graphics.gcolor module

Classes for manipulating colors and pixels.

A GColor is a heavy object representing an abstract color. It should be thought of as an opaque data type that can be initialized from any of several possible representations, and serialized to any of those representations.

A Pixel represents a single pixel of an image, and is stored much more efficiently. A Pixel can represent an (R, G, B) triplet or an (R, G, B, A) quadruplet.

The main difference between a Pixel and a GColor is that a Pixel is basically an efficiently stored integer representing the alpha, red, green, and blue channels of the pixel, whereas a GColor has no alpha channel and has many more utility methods attached.

Additionally, a Pixel is mutable, whereas a GColor is immutable.

class campy.graphics.gcolor.GColor(red, green, blue)

Bases: object

A GColor represents a color.

Colors can be represented in many different forms.

1. As a three-integer tuple, such as as (168, 0, 59), with each entry in the range 0..255
2. As a three-character hex string prefaced with ‘#’, such as “#83E”
3. As a six-character hex string prefaced with ‘#’, such as “#A8003B”
4. As a three-character hex string prefaced with ‘0x’, such as “0x83E”
5. As a six-character hex string prefaced with ‘0x’, such as “0xA8003B”
6. As a case-insensitive name, such as “red” or “LiGhT sKy BlUe”
7. As a GColor constant, such as GColor.RED or GColor.LIGHT_SKY_BLUE.
8. As a 24-bit integer, representing the red, green, and blue channels.
9. As a Pixel object, such as Pixel(168, 0, 59).

The canonical (internal) form for a GColor is as three integers between 0 and 255.

A GColor should be thought of as immutable.

b

classmethod brighten(color)

classmethod darken(color)

Construct a new color at 2/3 of the current color’s red, green, and blue values, rounded down.

g

hex

name

Return a human-readable name for this color.

classmethod normalize(color)

Normalize a color description provided by an end user.

r

rgb

class campy.graphics.gcolor.Pixel(red=0, green=0, blue=0, alpha=255)

Bases: object

A Pixel represents a single, possibly-transparent pixel from an image.

Students will likely never have to directly instantiate Pixels, and will instead likely just modify provided Pixels.

Pixels can be modified directly by getting or setting their properties.

To change the values of channels of a pixel:

cardinal = Pixel(168, 0, 59)
print(cardinal.red)  # => 168

cardinal.red = 223
cardinal.green = 202
cardinal.blue = 151

red, green, blue = cardinal.rgb()

To modify the alpha channel of a pixel, use the same syntax:

opaque = Pixel(168, 0, 59)
opaque.alpha //= 2
alpha, red, green, blue = opaque.argb()

The alpha channel of a pixel defaults to 255 if not otherwise set.

When setting values for these channels, it is required to supply an integer between 0 and 255, inclusive.

alpha

Get or set this Pixel’s alpha channel.

Usage:

pixel = Pixel(168, 0, 59)
pixel.alpha = 127
print(pixel.alpha)

argb()

Return a 4-tuple of this Pixel’s channels, including alpha transparency.

The elements of the tuple correspond to alpha, red, green, and blue.

To extract all channels at once:

pixel = Pixel(168, 0, 59)
alpha, red, green, blue = pixel.argb()

blue

Get or set this Pixel’s blue channel.

Usage:

pixel = Pixel(168, 0, 59)
pixel.blue = 41
print(pixel.blue)

green

Get or set this Pixel’s green channel.

Usage:

pixel = Pixel(168, 0, 59)
pixel.green = 41
print(pixel.green)

red

Get or set this Pixel’s red channel.

Usage:

pixel = Pixel(168, 0, 59)
pixel.red = 41
print(pixel.red)

rgb()

Return a 3-tuple of this Pixel’s channels, not including alpha transparency.

The elements of the tuple correspond to red, green, and blue.

To extract all color channels at once:

pixel = Pixel(168, 0, 59)
red, green, blue = pixel.rgb()