PngDrawer#
- class langchain_core.runnables.graph_png.PngDrawer(fontname: str | None = None, labels: LabelsDict | None = 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 (str | None) – The font to use for the labels. Defaults to “arial”.
labels (LabelsDict | None) –
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. Defaults to None.
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 edges to the graph.
add_node(viz, node)Adds a node to the graph.
add_nodes(viz, graph)Add nodes to the 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)Update the styles of the entrypoint and END nodes.
- __init__(fontname: str | None = None, labels: LabelsDict | None = None) None[source]#
Initializes the PNG drawer.
- Parameters:
fontname (str | None) – The font to use for the labels. Defaults to “arial”.
labels (LabelsDict | None) –
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. Defaults to None.
- Return type:
None
- add_edge(viz: Any, source: str, target: str, label: str | None = 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 (str | None) – 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]#
Add edges to the graph.
- Parameters:
viz (Any) – The graphviz object.
graph (Graph) – The graph to draw.
- 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]#
Add nodes to the graph.
- Parameters:
viz (Any) – The graphviz object.
graph (Graph) – The graph to draw.
- Return type:
None
- draw(graph: Graph, output_path: str | None = None) bytes | None[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 (str | None)
- Return type:
bytes | None
- 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