raygeo.image.ramp

Functions

edge_ramp()

edge_ramp(
    binary: numpy.NDArray[numpy.uint8],
    ramp_length_mm: float,
    pixels_per_mm: tuple[float, float] = (1, 1),
) -> numpy.NDArray[numpy.float32]

Distance of each burned pixel to the edge of the burned area.

For every nonzero pixel of binary, returns its distance to the edge of the burned area divided by ramp_length_mm and clamped to 1, so 0 is the edge and 1 is at or beyond the ramp length; zero pixels get 0. Pixels outside the image count as not burned. A stroke narrower than twice the ramp length never reaches 1.

The distance is Euclidean and in millimetres, so non-square pixels are handled. It runs from the pixel centre to the centre of the nearest unburned pixel, less the part of that line inside the unburned pixel: exact along the axes, and within half a pixel otherwise.

Used for sloped edges in relief and stamp engraving, where the power ramps up from the edge over the ramp length.

Raises: ValueError — If the ramp length or resolution is invalid.

Parameter	Type	Description
binary	numpy.NDArray[numpy.uint8]	2D uint8 array, nonzero marks a burned pixel.
ramp_length_mm	float	Ramp length in mm; 0 returns 0/1 floats.
pixels_per_mm	tuple[float, float] = (1, 1)	(x, y) image resolution in pixels per mm.
Returns	numpy.NDArray[numpy.float32]	2D float32 array of ramp fractions in [0, 1].
Complexity		O(w*h)