skidl.geometry module¶

Geometric primitives and transformations for SKiDL.

This module provides classes and functions to handle geometric operations needed for positioning and transforming components. It includes support for points/vectors, transformation matrices, and unit conversions between millimeters and thousandths-of-inch (mils).

class skidl.geometry.BBox(*pts)[source]¶

Bases: object

A bounding box defined by minimum and maximum points.

BBox represents a rectangular area that can contain points or other bounding boxes. It provides methods for combining bounding boxes, testing if points are inside, and calculating intersections.

Parameters:: *pts – One or more Point objects defining the initial bounding box.

add(*objs)[source]¶

Update the bounding box to include multiple points and/or bounding boxes.

Parameters:: *objs – Points or BBoxes to include in this bounding box.
Returns:: The updated bounding box (self).
Return type:: BBox

property area¶

Calculate the area of the bounding box.

Returns:: Area (width × height).
Return type:: float

property ctr¶

Get the center point of the bounding box.

Returns:: Center point.
Return type:: Point

property h¶

Get the height of the bounding box.

Returns:: Height of the bounding box.
Return type:: float

intersection(bbox)[source]¶

Calculate the intersection of this bounding box with another.

Parameters:

bbox (BBox) – Another bounding box.

Returns:

A new bounding box representing the intersection,: or None if there is no intersection.

Return type:

BBox or None

intersects(bbox)[source]¶

Check if this bounding box intersects with another.

Parameters:: bbox (BBox) – Another bounding box to check for intersection.
Returns:: True if the bounding boxes intersect.
Return type:: bool

is_inside(pt)[source]¶

Check if a point is inside or on the boundary of this bounding box.

Parameters:: pt (Point) – The point to check.
Returns:: True if the point is inside or on the boundary.
Return type:: bool

property ll¶

Get the lower-left corner of the bounding box.

Returns:: Lower-left corner point.
Return type:: Point

property lr¶

Get the lower-right corner of the bounding box.

Returns:: Lower-right corner point.
Return type:: Point

resize(vector)[source]¶

Expand or contract the bounding box by a given amount in all directions.

Parameters:: vector (Point) – Amount to expand by (positive values) or contract by (negative values) in x and y directions.
Returns:: A new resized bounding box.
Return type:: BBox

round()[source]¶

Round the bounding box limits to integers.

Returns:: A new bounding box with rounded coordinates.
Return type:: BBox

snap_resize(grid_spacing)[source]¶

Resize the bounding box to align min and max points to a grid.

This expands the bounding box outward so that its corners align with the given grid spacing.

Parameters:: grid_spacing (float) – Grid spacing to align to.
Returns:: A new bounding box with grid-aligned corners.
Return type:: BBox

property ul¶

Get the upper-left corner of the bounding box.

Returns:: Upper-left corner point.
Return type:: Point

property ur¶

Get the upper-right corner of the bounding box.

Returns:: Upper-right corner point.
Return type:: Point

property w¶: Return the bounding box width.

class skidl.geometry.Point(x, y)[source]¶

Bases: object

A 2D point or vector with x and y coordinates.

The Point class represents both points in space and vectors for geometric operations. It supports various arithmetic operations and can be transformed using the Tx transformation matrix.

Parameters:

x (float) – The x-coordinate.
y (float) – The y-coordinate.

flip_xy()[source]¶: Swap the x and y coordinates in place.

property magnitude¶

Calculate the distance of the point from origin (vector length).

Returns:: The Euclidean distance from origin.
Return type:: float

mask(msk)[source]¶

Apply a binary mask to the coordinates.

Parameters:: msk (list or tuple) – A pair of values to multiply with x and y.
Returns:: New point with masked coordinates.
Return type:: Point

max(pt)[source]¶

Create a new point using the maximum x and y from two points.

Parameters:: pt (Point) – Another point to compare with.
Returns:: New point with maximum x and y values.
Return type:: Point

min(pt)[source]¶

Create a new point using the minimum x and y from two points.

Parameters:: pt (Point) – Another point to compare with.
Returns:: New point with minimum x and y values.
Return type:: Point

property norm¶

Calculate a unit vector in the same direction.

Returns:: Normalized vector with length 1, or (0,0) if zero length.
Return type:: Point

round()[source]¶

Round coordinates to nearest integers.

Returns:: New point with rounded coordinates.
Return type:: Point

snap(grid_spacing)[source]¶

Snap point coordinates to a grid.

Parameters:: grid_spacing (float) – Grid interval to snap to.
Returns:: New point with coordinates snapped to the grid.
Return type:: Point

xprod(pt)[source]¶

Calculate the cross product of this vector and another.

For 2D vectors, the cross product returns a scalar representing the z-component of the 3D cross product.

Parameters:: pt (Point) – Another point/vector.
Returns:: The cross product value.
Return type:: float

class skidl.geometry.Segment(p1, p2)[source]¶

Bases: object

A line segment between two points.

Represents a straight line segment with endpoints p1 and p2.

Parameters:

p1 (Point) – First endpoint.
p2 (Point) – Second endpoint.

flip_xy()[source]¶: Swap the x and y coordinates of both endpoints.

intersects(other)[source]¶

Check if this segment intersects with another segment.

Note: This method is not fully implemented and will raise an error.

Parameters:: other (Segment) – Another segment to check for intersection.
Raises:: NotImplementedError – This method is not fully implemented.

round()[source]¶

Round the segment endpoints to integers.

Returns:: A new segment with rounded endpoint coordinates.
Return type:: Segment

shadows(other)[source]¶

Check if two segments overlap when projected onto axes.

This tests if the segments would overlap when viewed from above or the side, even if they don’t physically intersect.

Parameters:: other (Segment) – Another segment to check.
Returns:: True if segments shadow (overlap) each other on x or y axis.
Return type:: bool

class skidl.geometry.Tx(a=1, b=0, c=0, d=1, dx=0, dy=0)[source]¶

Bases: object

A 2D transformation matrix for geometric operations.

This class implements a 3x3 transformation matrix for 2D operations like rotation, scaling, flipping, and translation. The matrix has the following structure:

[ a b 0 ] [ c d 0 ] [ dx dy 1 ]

Where the transformed coordinates are calculated as: x’ = a*x + c*y + dx y’ = b*x + d*y + dy

Parameters:

a (float, optional) – Scaling/rotation factor for x coordinate. Defaults to 1.
b (float, optional) – Rotation factor for y contribution to x. Defaults to 0.
c (float, optional) – Rotation factor for x contribution to y. Defaults to 0.
d (float, optional) – Scaling/rotation factor for y coordinate. Defaults to 1.
dx (float, optional) – Translation in x direction. Defaults to 0.
dy (float, optional) – Translation in y direction. Defaults to 0.

flip_x()[source]¶

Return a new Tx with a horizontal flip (mirror across y-axis).

Returns:: A new transformation matrix with the flip applied.
Return type:: Tx

flip_y()[source]¶

Return a new Tx with a vertical flip (mirror across x-axis).

Returns:: A new transformation matrix with the flip applied.
Return type:: Tx

classmethod from_symtx(symtx)[source]¶

Create a transformation matrix from a string of symbolic operations.

Parameters:: symtx (str) – A string of H, V, L, R operations that are applied in sequence left-to-right. H = horizontal flip, V = vertical flip, L = rotate 90° left (CCW), R = rotate 90° right (CW)
Returns:: A transformation matrix that implements the sequence of operations.
Return type:: Tx

Examples

>>> tx = Tx.from_symtx("RH")  # Rotate right, then flip horizontally

move(vec)[source]¶

Return a new Tx with an additional translation applied.

Parameters:: vec (Point) – The vector to translate by.
Returns:: A new transformation matrix with the translation applied.
Return type:: Tx

no_translate()[source]¶

Return a new Tx with the same rotation/scaling but no translation.

Returns:: A new transformation matrix with translation set to (0,0).
Return type:: Tx

property origin¶

Get the translation component of the transformation.

Returns:: A Point object representing the (dx, dy) translation.
Return type:: Point

rot(degs)[source]¶

Return a new Tx with a rotation by the given angle in degrees.

Parameters:: degs (float) – The rotation angle in degrees.
Returns:: A new transformation matrix with the rotation applied.
Return type:: Tx

rot_90cw()[source]¶

Return a new Tx with a 90-degree clockwise rotation applied.

Returns:: A new transformation matrix with the rotation applied.
Return type:: Tx

property scale¶

Get the scaling factor of the transformation.

This calculates the length of a unit vector after transformation.

Returns:: The scaling factor.
Return type:: float

skidl.geometry.Vector¶: alias of Point

skidl.geometry.to_mils(mm)[source]¶

Convert millimeters to thousandths-of-inch (mils).

Parameters:: mm (float) – Value in millimeters.
Returns:: Equivalent value in mils.
Return type:: float

skidl.geometry.to_mms(mils)[source]¶

Convert thousandths-of-inch (mils) to millimeters.

Parameters:: mils (float) – Value in mils.
Returns:: Equivalent value in millimeters.
Return type:: float

skidl.geometry module¶

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