Animating Trees

Manim Tree - MTree

In this section, you’ll find all the methods available to manipulate a MTree (short for Manim Tree 😄). Like all MObject structures, you can animate these methods using the .animate method, allowing you to animate each operation provided by Manim DSA. Otherwise, methods will run without any animations.

As with other data structures provided by the library, you can access individual nodes and edges in an MTree using the [] operator. To access a node, specify its name. To access an edge, use a tuple containing the names of the two nodes it connects.

Creating a MTree

You can create a tree by initializing an MTree object. The first parameter defines the nodes and edges of the tree, which can be specified using one of the following structures:

type GraphType = (
    nx.DiGraph
    # Example: [['1','2'], ['0'], ['0']] is (1)---(0)---(2)
    | list[list[str]]
    # Example: {'A':['B','C'], 'B':[], 'C':[]]} is (B)<--(A)-->(C)
    | dict[str, list[str]]
    # Example: [[('1', 3), ('2', 1)], [('0', 3)], [('0', 1)]] is (1)--<3>-(0)-<1>--(2)
    | list[list[tuple[str, str | int]]]
    # Example: {'A':[('B', 9), ('C', 2)], 'B':[], 'C':[]} is (B)<-<9>-(A)-<2>->(C)
    | dict[str, list[tuple[str, str | int]]]
)

The second parameter allows you to specify the root node of the tree. If not specified, topological sorting is used to determine the root node.

Additionally, you can customize the theme of the MTree (see Customizing a MTree).

Below are two examples of creating a tree:

1. A tree of 7 nodes without specifying names.

2. A tree where nodes have specified names and edges have weights.

Example: BasicTree

from manim import *

from manim_dsa import *

class BasicTree(Scene):
    def construct(self):
        tree = [["1", "2"], ["3", "4"], ["5", "6"], [], [], [], []]
        mTree = MTree(tree)
        self.play(Create(mTree))
        self.wait()

Example: AdvancedTree

from manim import *

from manim_dsa import *

class AdvancedTree(Scene):
    def construct(self):
        tree = {
            "0": [("1", 5), ("2", 3)],
            "1": [("3", 2), ("4", 7)],
            "2": [("5", 4), ("6", 1)],
            "3": [("7", 6), ("8", 3)],
            "4": [("9", 2)],
            "5": [("11", 8), ("12", 5)],
            "6": [],
            "7": [],
            "8": [],
            "9": [],
            "11": [],
            "12": [],
        }
        mTree = MTree(tree)
        self.play(Create(mTree))
        self.wait()

Note how the node positioning is performed automatically using a hierarchical layout!

Customizing a MTree

ManimDSA provides various options for customizing the colors and styles of a MTree. You can use these options by passing a predefined style configuration from the MTreeStyle class using the style parameter. Refer to MTreeStyle for more details. Alternatively, you can define a custom style to suit your needs.

In the following example, we use the PURPLE style for the MTree.

Example: CustomCreation

from manim import *

from manim_dsa import *

class CustomCreation(Scene):
    def construct(self):
        tree = {
            "0": [("1", 5), ("2", 3)],
            "1": [("3", 2), ("4", 7)],
            "2": [("5", 4), ("6", 1)],
            "3": [("7", 6), ("8", 3)],
            "4": [("9", 2)],
            "5": [("11", 8), ("12", 5)],
            "6": [],
            "7": [],
            "8": [],
            "9": [],
            "11": [],
            "12": [],
        }
        mTree = MTree(tree, style=MTreeStyle.PURPLE)
        self.play(Create(mTree))
        self.wait()