CurveSegment

The CurveSegment class represents an individual segment of a Curve path— a straight line or cubic Bézier curve defined by a start point, an end point, and two control handles.

After loading a model and retrieving a Curve, you can:

Get a specific segment by index with get_segment().
Iterate all segments via get_segments_list() or the segments property.

Example:

import sbmlnetwork as sn

net = sn.load("my_model.xml")

# Get reaction id
reaction_id = net.get_reaction_ids()[0]

# Get curve segment coordinates
curve = net.get_reaction(reaction_id).get_curves_list()[0]
seg = curve.get_segment(0)
print(seg.get_start(), seg.get_end())

Core Methods

Identification

get_curve_segment_index()

Return the zero-based index of this segment within its parent Curve.

Return type:: int

Endpoints

get_start()

Return the starting point (x, y) of the segment.

Return type:: tuple[float, float]

set_start(start)

Move the start point to the given (x, y) coordinates.

Parameters:: start – New start coordinates.

get_end()

Return the end point (x, y) of the segment.

Return type:: tuple[float, float]

set_end(end)

Move the end point to the given (x, y) coordinates.

Parameters:: end – New end coordinates.

Control Points

get_control_point_1()

Return the first Bézier control handle (x, y).

Return type:: tuple[float, float]

set_control_point_1(control_point_1)

Set the first control handle to the given coordinates.

Parameters:: control_point_1 – New control point (x, y).

get_control_point_2()

Return the second Bézier control handle (x, y).

Return type:: tuple[float, float]

set_control_point_2(control_point_2)

Set the second control handle to the given coordinates.

Parameters:: control_point_2 – New control point (x, y).

Movement

move_by(delta)

Translate this segment by the given offset, moving start, end, and control points.

Parameters:: delta – Offset (dx, dy).

move_start_to(position)

Move the start point to absolute coordinates, adjusting the first control point.

Parameters:: position – New start (x, y).

move_start_by(delta)

Move the start point and first control point by (dx, dy).

Parameters:: delta – Offset (dx, dy).

move_end_to(position)

Move the end point to absolute coordinates, adjusting the second control point.

Parameters:: position – New end (x, y).

move_end_by(delta)

Move the end point and second control point by (dx, dy).

Parameters:: delta – Offset (dx, dy).

Information

property info

Human-readable summary of glyph state for debugging.

Return type:: str

get_info(): Generate the info string.

Example workflow

import sbmlnetwork as sn

# Load the SBML network and retrieve a reaction segment
net = sn.load("my_model.xml")

segment = net.get_reactions_list()[0].get_curves_list()[0].get_segment(0)

# Inspect endpoints and handles
print("Start            :", segment.start)
print("Control point 1  :", segment.control_point_1)
print("Control point 2  :", segment.control_point_2)
print("End              :", segment.end)

# Move the entire segment
segment.move_by((5, -10))

# Debug summary
print(segment.info)