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Render options

See the official Mermaid documentation for additional information.

c4.renderers.mermaid.options.MermaidRenderOptionsBuilder

Builder for constructing MermaidRenderOptions.

Provides a fluent API for incrementally defining styles and layout configuration.

update_element_style 

update_element_style(
    element: str | Element,
    bg_color: str | None = None,
    font_color: str | None = None,
    border_color: str | None = None,
) -> Self

Adds an UpdateElementStyle() macro configuration.

Parameters:

Name Type Description Default
element str | Element

Element or alias of the element to style.

 required
bg_color str | None

Background color of the element.

 None
font_color str | None

Text color of the element label.

 None
border_color str | None

Border color of the element.

 None

Returns:

Type Description
Self

The updated render options.

update_rel_style 

update_rel_style(
    from_element: str | Element,
    to_element: str | Element,
    text_color: str | None = None,
    line_color: str | None = None,
    offset_x: int | None = None,
    offset_y: int | None = None,
) -> Self

Adds an UpdateRelStyle() macro configuration.

Parameters:

Name Type Description Default
from_element str | Element

Element or alias of the source element.

 required
to_element str | Element

Element or alias of the target element.

 required
text_color str | None

Color of the relationship label text.

 None
line_color str | None

Color of the connecting line.

 None
offset_x int | None

Optional horizontal offset for the label position.

 None
offset_y int | None

Optional vertical offset for the label position.

 None

Returns:

Type Description
Self

The updated render options.

update_layout_config 

update_layout_config(
    c4_shape_in_row: int | None = None,
    c4_boundary_in_row: int | None = None,
) -> Self

Override default Mermaid layout configuration.

Parameters:

Name Type Description Default
c4_shape_in_row int | None

Maximum number of non-boundary elements (e.g. systems, containers, components) per row. Default in Mermaid: 4.

 None
c4_boundary_in_row int | None

Maximum number of boundaries per row. Default in Mermaid: 2.

 None

Returns:

Type Description
Self

The updated render options.

build 

build() -> MermaidRenderOptions

Build and return the final MermaidRenderOptions instance.

c4.renderers.mermaid.options.MermaidRenderOptions dataclass

Final render options for rendering a Mermaid C4 diagram.

This includes style overrides and layout configuration that will be translated into Mermaid directives/macros during rendering.

Attributes:

Name Type Description
styles list[BaseStyle]

Collection of style overrides applied to elements and relationships.
update_layout_config UpdateLayoutConfig | None

Optional layout configuration override. If not provided, Mermaid defaults are used.
Source code in c4/renderers/mermaid/options.py 
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@dataclass
class MermaidRenderOptions:
    """
    Final render options for rendering a Mermaid C4 diagram.

    This includes style overrides and layout configuration that will be
    translated into Mermaid directives/macros during rendering.

    Attributes:
        styles: Collection of style overrides applied to elements
            and relationships.
        update_layout_config: Optional layout configuration override.
            If not provided, Mermaid defaults are used.
    """

    styles: list[BaseStyle] = field(default_factory=list)
    update_layout_config: UpdateLayoutConfig | None = None