Label

The Label class defines the textual annotations attached to a network element (such as a Compartment, Species, or Reaction). A Label stores the displayed text, its position, and optional styling like font size, colour, or alignment. Every visual object on the canvas can have multiple Labels to describe different features or details.

After loading a model and retrieving a network element, you can:

Get the first Label for that element with get_label().
Retrieve all Label objects attached to the element with get_labels_list().

Example:

import sbmlnetwork as sn

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

# Get Species ids
species_ids = net.get_species_ids()

# First label for a specific species
species_label = net.get_species(species_ids[0]).get_label()
print(species_label.get_text(), species_label.get_position())

# Add a new label to the first species
new_label = net.get_species(species_ids[0]).add_label("New Label", relative_position=(10, 10))

# All labels for the same species
for label in net.get_species(species_ids[0]).get_labels_list():
    print(label.get_text(), label.get_position())

Core Methods

Identificaiton

get_element_id()

Return the SBML identifier of the parent network element this Label belongs to.

Return type:: str

get_text()

Return the text content of this Label.

Return type:: str

set_text(text)

Set the text content of this Label.

Parameters:: text (str) – New text for the label.

Size & Placement

get_position()

Return the absolute diagram coordinates (x, y) of this Label’s origin.

Return type:: tuple[float, float]

set_position(position)

Set the Label’s absolute position to the given (x, y) coordinates.

Parameters:: position (tuple[float, float]) – New position in diagram units.

get_relative_position()

Return the Label’s position relative to its parent element’s origin.

Return type:: tuple[float, float]

set_relative_position(relative_position)

Set the Label’s position relative to its parent element’s origin.

Parameters:: relative_position (tuple[float, float]) – Offset (dx, dy) from the parent element.

get_size()

Return the width and height of the Label’s bounding box.

Return type:: tuple[float, float]

set_size(size)

Set the width and height of the Label’s bounding box.

Parameters:: size (tuple[float, float]) – New (width, height) in diagram units.

Alignment Helpers

align_to_left(): Align the text to the left edge of its bounding box.

align_to_horizontal_center(): Center the text horizontally within its bounding box.

align_to_right(): Align the text to the right edge of its bounding box.

get_horizontal_alignment(): Return the current horizontal alignment as one of “left”, “center”, or “right”.

align_to_top(): Align the text to the top edge of its bounding box.

align_to_vertical_center(): Center the text vertically within its bounding box.

align_to_baseline(): Align the text to its font baseline within the bounding box.

align_to_bottom(): Align the text to the bottom edge of its bounding box.

get_vertical_alignment(): Return the current vertical alignment as one of “top”, “center”, “baseline”, or “bottom”.

Styling

get_font()

Return the font family used by this Label.

Return type:: str

set_font(font_family)

Set the font family for this Label.

Parameters:: font_family (str) – Name of an installed font (e.g. “Helvetica”).

get_font_size()

Return the font size in diagram units (or points).

Return type:: float

set_font_size(font_size)

Set the font size for this Label.

Parameters:: font_size (float) – Size in diagram units (or points).

get_font_color()

Return the font colour as a hex string or RGB tuple.

Return type:: str or tuple[int, int, int]

set_font_color(font_color)

Set the font colour.

Parameters:: font_color (str or tuple[int, int, int]) – Hex string (e.g. “#rrggbb”) or RGB tuple (r, g, b).

set_bold(bold=True)

Enable or disable bold text.

Parameters:: bold – True to set weight to “bold”, False for “normal”.

is_bold()

Return whether the text weight is currently bold.

Return type:: bool

set_italic(italic=True)

Enable or disable italic text.

Parameters:: italic – True to set style to “italic”, False for “normal”.

is_italic()

Return whether the text style is currently italic.

Return type:: bool

Information

property info

Human-readable summary of glyph state for debugging.

Return type:: str

get_info(): Generate the info string.

Example workflow

The script below demonstrates how to discover Labels, inspect and update their content, styling, and placement, then re-render the diagram.

import sbmlnetwork as sn

# Load the SBML model
net = sn.load("my_model.xml")

# Get the first Label for a species
species = net.get_species_list()[0]
label = species.get_label()

# Inspect current state
print("Text     :", label.get_text())
print("Position :", label.get_position())
print("Size     :", label.get_size())

# Modify text content
label.set_text("ATP")

# Update styling
label.set_font("Arial")
label.set_font_size(12)
label.set_font_color("#cc6633")
label.set_bold(True)
label.set_italic(False)

# Update placement and alignment
label.set_position((150.0, 80.0))
label.align_to_horizontal_center()
label.align_to_vertical_center()

# Re-render to file
net.draw("updated_diagram.png")