an.paint

Paint: what fills a shape when one flat colour is not enough – a gradient.

A gradient blends colour stops (CSS’s color stops: a colour at an offset from 0 to 1 along the gradient) either along a line (linear) or outward from a centre (radial). The vocabulary is CSS’s (linear-gradient / radial-gradient), so an author who knows one knows the other:

• angle (linear) is the CSS gradient angle in degrees: 0 runs to the top, 90 to the right, 180 (the default) to the bottom. As in CSS the gradient line is as long as it must be for the box’s corners to sit on the first and last stop.

• center and radius (radial) are fractions of the box. In a box that is not square the gradient is an ellipse with the box’s proportions (CSS’s ellipse); radius: 0.5 touches the sides of a centred box.

• Colours between stops are interpolated in sRGB, as CSS and SVG do by default; beyond the first and last stop the end colours hold.

Colours are hex strings (#rgb, #rgba, #rrggbb, #rrggbbaa), the representation the StylePack uses everywhere. Stops may be written as plain colours, which are spread evenly:

>>> g = Gradient(stops=["#101030", "#f0d090"])
>>> [(s.offset, s.color) for s in g.stops]
[(0.0, '#101030'), (1.0, '#f0d090')]
>>> Gradient(type="radial", stops=["#fff", "#0000"], radius=0.75).radius
0.75

A field that would do nothing is refused rather than ignored:

>>> Gradient(type="radial", stops=["#fff", "#000"], angle=90)
Traceback (most recent call last):
...
pydantic_core._pydantic_core.ValidationError: ...

This is genre-neutral core vocabulary: a plane of the 2D stage draws one (an.stage.environments.PlaneArt), and a StylePack names them as gradient roles (an.styles.StylePack.gradients).

Module Attributes

DFLT_GRADIENT_ANGLE

top to bottom.

Functions

rgba_of(color)

A hex colour as (r, g, b, a) in 0..1.

Classes

Gradient(**data)	A linear or radial gradient between colour stops (see the module docstring).
GradientStop(**data)	A colour at an offset along the gradient (0 start, 1 end).

an.paint.DFLT_GRADIENT_ANGLE: float = 180.0

top to bottom.

Type:

CSS’s default gradient direction

class an.paint.Gradient(**data)

Bases: BaseModel

A linear or radial gradient between colour stops (see the module docstring).

angle: float

the CSS gradient angle, degrees (0 up, 90 right, 180 down).

Type:

Linear only

center: tuple[float, float]

the centre, in fractions of the box.

Type:

Radial only

model_config: ClassVar[ConfigDict] = {'extra': 'forbid'}

Configuration for the model, should be a dictionary conforming to [ConfigDict][pydantic.config.ConfigDict].

radius: float

the radius, in fractions of the box (an ellipse in a non-square box).

Type:

Radial only

class an.paint.GradientStop(**data)

Bases: BaseModel

A colour at an offset along the gradient (0 start, 1 end).

model_config: ClassVar[ConfigDict] = {'extra': 'forbid'}

Configuration for the model, should be a dictionary conforming to [ConfigDict][pydantic.config.ConfigDict].

an.paint.rgba_of(color)

A hex colour as (r, g, b, a) in 0..1.

Return type:

tuple[float, float, float, float]

>>> rgba_of("#ff000080")
(1.0, 0.0, 0.0, 0.5019607843137255)