langchain_core.runnables.graph_png.PngDrawer¶
- class langchain_core.runnables.graph_png.PngDrawer(fontname: Optional[str] = None, labels: Optional[LabelsDict] = None)[source]¶
Helper class to draw a state graph into a PNG file.
It requires graphviz and pygraphviz to be installed. :param fontname: The font to use for the labels :param labels: A dictionary of label overrides. The dictionary
should have the following format: {
- “nodes”: {
“node1”: “CustomLabel1”, “node2”: “CustomLabel2”, “__end__”: “End Node”
}, “edges”: {
“continue”: “ContinueLabel”, “end”: “EndLabel”
}
} The keys are the original labels, and the values are the new labels.
- Usage:
drawer = PngDrawer() drawer.draw(state_graph, ‘graph.png’)
Initializes the PNG drawer.
- Parameters
fontname (Optional[str]) – The font to use for the labels
labels (Optional[LabelsDict]) –
A dictionary of label overrides. The dictionary should have the following format: {
- ”nodes”: {
“node1”: “CustomLabel1”, “node2”: “CustomLabel2”, “__end__”: “End Node”
}, “edges”: {
”continue”: “ContinueLabel”, “end”: “EndLabel”
}
} The keys are the original labels, and the values are the new labels.
Methods
__init__([fontname, labels])Initializes the PNG drawer.
add_edge(viz, source, target[, label, ...])Adds an edge to the graph.
add_edges(viz, graph)add_node(viz, node)Adds a node to the graph.
add_nodes(viz, graph)draw(graph[, output_path])Draw the given state graph into a PNG file.
get_edge_label(label)Returns the label to use for an edge.
get_node_label(label)Returns the label to use for a node.
update_styles(viz, graph)- __init__(fontname: Optional[str] = None, labels: Optional[LabelsDict] = None) None[source]¶
Initializes the PNG drawer.
- Parameters
fontname (Optional[str]) – The font to use for the labels
labels (Optional[LabelsDict]) –
A dictionary of label overrides. The dictionary should have the following format: {
- ”nodes”: {
“node1”: “CustomLabel1”, “node2”: “CustomLabel2”, “__end__”: “End Node”
}, “edges”: {
”continue”: “ContinueLabel”, “end”: “EndLabel”
}
} The keys are the original labels, and the values are the new labels.
- Return type
None
- add_edge(viz: Any, source: str, target: str, label: Optional[str] = None, conditional: bool = False) None[source]¶
Adds an edge to the graph.
- Parameters
viz (Any) – The graphviz object
source (str) – The source node
target (str) – The target node
label (Optional[str]) – The label for the edge. Defaults to None.
conditional (bool) – Whether the edge is conditional. Defaults to False.
- Returns
None
- Return type
None
- add_edges(viz: Any, graph: Graph) None[source]¶
- Parameters
viz (Any) –
graph (Graph) –
- Return type
None
- add_node(viz: Any, node: str) None[source]¶
Adds a node to the graph.
- Parameters
viz (Any) – The graphviz object
node (str) – The node to add
- Returns
None
- Return type
None
- add_nodes(viz: Any, graph: Graph) None[source]¶
- Parameters
viz (Any) –
graph (Graph) –
- Return type
None
- draw(graph: Graph, output_path: Optional[str] = None) Optional[bytes][source]¶
Draw the given state graph into a PNG file.
Requires graphviz and pygraphviz to be installed. :param graph: The graph to draw :param output_path: The path to save the PNG. If None, PNG bytes are returned.
- Parameters
graph (Graph) –
output_path (Optional[str]) –
- Return type
Optional[bytes]
- get_edge_label(label: str) str[source]¶
Returns the label to use for an edge.
- Parameters
label (str) – The original label
- Returns
The new label.
- Return type
str