graphviz

Functionality to display the tracer as a visual graph.

It first convert it to a graph, using visual_graph.py, and then renders that with graphviz.

add_legend(dot, options)

Add a legend with nodes and edge styles.

Creates one node for each node style and one edge for each edge style.

It was difficult to get it to appear in a way that didn't disrupt the main graph. It was easiest to get it to be a vertically aligned column of nodes, on the left of the graph. To do this, I link all the nodes with invisible edges so they stay vertically aligned.

https://stackoverflow.com/a/52300532/907060.

Source code in lineapy/visualizer/graphviz.py

def add_legend(dot: graphviz.Digraph, options: VisualGraphOptions):
    """
    Add a legend with nodes and edge styles.

    Creates one node for each node style and one edge for each edge style.

    It was difficult to get it to appear in a way that didn't disrupt the  main
    graph. It was easiest to get it to be a vertically aligned column of nodes,
    on the left of the graph. To do this, I link all the nodes with invisible
    edges so they stay vertically aligned.

    https://stackoverflow.com/a/52300532/907060.
    """
    with dot.subgraph(name="cluster_0") as c:
        c.attr(color=CLUSTER_EDGE_COLOR)
        c.attr(label="Legend")

        ##
        # Add nodes to legend
        ##

        # Save the previous ID so we can add an invisible edge.
        prev_id: Optional[str] = None
        for node_type, label in NODE_LABELS.items():
            id_ = f"legend_node_{label}"

            extra_labels: ExtraLabels = []
            # If this isn't in the first node, add an invisible edge from
            # the previous node to it.
            if prev_id:
                c.edge(prev_id, id_, style="invis")
            # If this is the first node, add sample extra labels
            else:
                for v, extra_label_label in extra_label_labels(
                    options
                ).items():
                    extra_labels.append(ExtraLabel(extra_label_label, v))
            render_node(
                c,
                VisualNode(id_, node_type, label, extra_labels),
                fontname=SERIF_FONT,
            )
            prev_id = id_

        ##
        # Add edges to legend
        ##
        edges_for_legend = edge_labels(options)
        if edges_for_legend:
            # Keep adding invisible edges, so that all of the nodes are aligned vertically
            id_ = "legend_edge"
            c.node(id_, "", shape="box", style="invis")
            c.edge(prev_id, id_, style="invis")
            prev_id = id_
            for edge_type, label in edges_for_legend.items():
                id_ = f"legend_edge_{label}"
                # Add invisible nodes, so the edges have something to point to.
                c.node(id_, "", shape="box", style="invis")
                c.edge(
                    prev_id,
                    id_,
                    label=label,
                    **edge_type_to_kwargs(edge_type, highlighted=True),
                )
                prev_id = id_
    return id_

edge_labels(options)

Labels for the edge types to use in the legend,

Source code in lineapy/visualizer/graphviz.py

def edge_labels(
    options: VisualGraphOptions,
) -> Dict[VisualEdgeType, str]:
    """
    Labels for the edge types to use in the legend,
    """
    l: Dict[VisualEdgeType, str] = {
        VisualEdgeType.SOURCE_CODE: "Source Code",
        VisualEdgeType.MUTATE_CALL: "Mutate Call",
        VisualEdgeType.IMPLICIT_DEPENDENCY: "Implicit Dependency",
        VisualEdgeType.CONTROL_DEPENDENCY: "Control Flow",
    }
    if options.show_implied_mutations:
        l[VisualEdgeType.LATEST_MUTATE_SOURCE] = "Implied Mutate"
    if options.show_views:
        l[VisualEdgeType.VIEW] = "View"
    return l

extra_label_labels(options)

Labels for the extra label, to use in the legend,

Source code in lineapy/visualizer/graphviz.py

def extra_label_labels(
    options: VisualGraphOptions,
) -> Dict[ExtraLabelType, str]:
    """
    Labels for the extra label, to use in the legend,
    """
    l: Dict[ExtraLabelType, str] = {}
    if options.show_artifacts:
        l[ExtraLabelType.ARTIFACT] = "Artifact Name"
    if options.show_variables:
        l[ExtraLabelType.VARIABLE] = "Variable Name"
    return l

extra_labels_to_html(extra_labels, highlighted)

Convert extra labels into an HTML table, where each label is a row. A single node could have multiple variables and artifacts pointing at it. So we make a table with a row for each artifact. Why a table? Well we are putting it in the xlabel and a table was an easy way to have multiple rows with different colors.

Source code in lineapy/visualizer/graphviz.py

def extra_labels_to_html(extra_labels: ExtraLabels, highlighted: bool) -> str:
    """
    Convert extra labels into an HTML table, where each label is a row.
    A single node could have multiple variables and artifacts pointing at it.
    So we make a table with a row for each artifact. Why a table? Well we are putting
    it in the xlabel and a table was an easy way to have multiple rows with different colors.
    """
    rows = [
        f'<TR ><TD BGCOLOR="{get_color(el.type, highlighted)}"><FONT POINT-SIZE="10">{el.label}</FONT></TD></TR>'
        for el in extra_labels
    ]
    return f'<<TABLE BORDER="0" CELLBORDER="0" CELLSPACING="0">{"".join(rows)}</TABLE>>'

get_color(tp, highlighted)

Get the color for a type. Note that graphviz colorscheme indexing is 1 based

Source code in lineapy/visualizer/graphviz.py

def get_color(tp: ColorableType, highlighted: bool) -> str:
    """
    Get the color for a type. Note that graphviz colorscheme indexing
    is 1 based
    """
    return color(COLORS[tp], highlighted)

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