Python Library¶

The interpreter uses manim to create animations for your code and the following prebuilt Python libraries define the standard visualisation for different data structures. Although this is a fixed standard way of representing data structures, you are able to change the style attributes through the stylesheet or even modify our functions to represent data structures the way you want! For more information on the stylesheet, check out the Customising Your Animation section.

All of the utility functions can be found at src/main/resources/python/util.py, and all of the shapes and data structures are in their own class (i.e. RectangleBlock is in src/main/resources/python/rectangle.py)

Data Structure¶

This is the abstract base class that defines the common fields and functions shared across all the data structures.

Constructor¶

The constructor of the most generic data structure takes in the following:

ul - the coordinates of the upper-left corner of the boundary for the data structure
ur - the coordinates of the upper-right corner of the boundary for the data structure
ll - the coordinates of the lower-left corner of the boundary for the data structure
lr - the coordinates of the lower-right corner of the boundary for the data structure
aligned_edge - the edge towards which the data structure will be scaled if it grows out of the boundary (only applies if the data structure is dynamic in size)
color - the color of the shapes visualised as part of the data structure [Optional - defaults to WHITE ]
text_color - the color of the text label visualised as part of the data structure [Optional - defaults to WHITE ]
text_weight - the weight of the text label visualised as part of the data structure [Optional - defaults to NORMAL ]
font - the font of the text label visualised as part of the data structure [Optional - defaults to "Times New Roman" ]

Inbuilt Functions¶

Any data structure has the following inbuilt functions implemented:

`shrink(self, new_width, new_height)`¶

Resizes the entire data structure by calculating a scale factor based on new_width and new_height provided.

In most cases, the scaling will be done directly, aligning to aligned_edge; however, the function shrink2 provides an alternative way of scaling the data structure in place and then moving it to align the aligned_edge.

`will_cross_boundary(self, object_dim, boundary_name)`¶

Checks if the given dimension object_dim will cross the boundary specified by boundary_name. The check is done by calling the corresponding function will_cross_top_boundary, will_cross_bottom_boundary, will_cross_right_boundary or will_cross_left_boundary.

`add(self, obj)`¶

Adds the given obj into the VGroup that holds all components of the data structure.

Abstract Methods¶

The following abstract methods are to be implemented by any data structure class, as different data structures may have different implementations.

`create_init(self, ident)`¶

Creates an initial visualisation of the data structure with the label ident when it’s instantiated.

`shrink_if_cross_boundary(self, obj)`¶

Checks if the data structure is growing out of the boundary when obj is added and resizes the data structure if necessary.

`clean_up(self)`¶

Cleans up the current data structure visualisation, which is helpful when a data structure is no longer used. The most common way of doing this is to fade out the data structure visualisation using FadeOut.

Stack¶

Constructor¶

The constructor of Stack takes in the exact same arguments as Data Structure with the same default values.

Inbuilt Functions¶

`push(self, obj, creation_style=None)`¶

Animates the push operation of a new item obj. The animation consists of visualising the creation of the obj using creation_style (optional and defaults to "FadeIn"), as well as moving obj to the top of the stack.

`push_existing(self, obj)`¶

Animates a special form of push operation when the item to be pushed - obj - has been created already. The animation would use the existing obj and push it onto the stack.

`pop(self, obj, fade_out=True)`¶

Animates the pop operation. The animation consists of moving the obj off the stack and (optionally) fade out obj if it’s no longer being used.

Array (1D)¶

Constructor¶

The constructor of Array takes in the following:

values - list of values corresponding to each index of the array
title - the text label to be displayed with the array
boundaries - coordinates of boundary that the array has to stay within
padding - specifies whether to add a padding between the title and the shape visualisation [Optional - defaults to True ]
color and text_color - same as for all data structures [Optional - color defaults to BLUE and text_color defaults to WHITE ]

Inbuilt Functions¶

`build(self, coord=None)`¶

Arranges each element of the array to be next to each other and adds in the title on the left of the array. The final Array object is then returned.

The optional argument coord specifies the left most coordinate of the array (defaults to where the title is), which is particularly useful when the array elements are updated.

`swap_mobjects(self, i1, i2)`¶

Animates the normal “quick” swap method, which swaps the 2 elements at i1 and i2 directly.

`clone_and_swap(self, i1, i2)`¶

Animates the special form of swap when longSwap is set to true. This would create a visualisation of the temp variable (a clone) and its usage, which is often seen when swapping array elements programmatically.

`update_element(self, idx, v, color=None)`¶

Animates updating the element at index idx with value v. The optional argument color represents the new color of the text that corresponds to the specific element (defaults to None, which is the original text_color).

`update_array_elements(self)`¶

Helper function for append that updates the array elements stored so far and recomputes the new dimension for the array (so that it fits within the boundary).

`append(self, v)`¶

Since the List data structure has been added using the existing Array data structure, this function animates the append method supported by List. This would visualise adding a new element with value v at the end of a resizable List.

Array 2D¶

Constructor¶

The constructor of 2D Array takes in the many of the same arguments as normal Array does, with the following differences:

values - list of lists of values corresponding to each element of the array
no padding argument required

Inbuilt Functions¶

`build(self, creation_style=None)`¶

Animates the creation of a 2D Array with the optional creation_style (defaults to FadeIn).

`replace_row(self, row_index, new_values)`¶

Animates updating the row specified by row_index with the given values new_values, which normally corresponds to a row assignment of a 2D Array.

`swap_mobjects(self, i1, j1, i2, j2)`¶

Animates swapping 2 elements of the 2D Array specified by (i1, j1) and (i2, j2). The visualisation would first dim the rest of the 2D Array to indicate which elements are being swapped, before fading the rest of the array back to the original text_color.

Tree¶

Constructor¶

The constructor of Tree takes in the many of the same arguments as Data Structure with the same default values. The different ones are as follows:

root - the root node of the tree
identifier - text label for the tree
radius - radius of the node of the tree [Optional - defaults to 0.6 ]
color - same as Data Structures but defaults to RED
text_color - same as Data Structures but defaults to BLUE

Inbuilt Functions¶

`update_root(self, node)`¶

Updates the root of the tree with node.

`check_if_child_will_cross_boundary(self, parent, child, is_left)`¶

Checks whether adding child will make the tree with parent cross the boundary. The is_left flag indicates which side the child will be added.

`set_right(self, parent, child)`¶

Animates setting child as the right child of parent. Assumes that parent is in the tree. The check for scaling and the corresponding animations are also done by calling _resize_after_modification.

`set_left(self, parent, child)`¶

Animates setting child as the left child of parent. Assumes that parent is in the tree. The check for scaling and the corresponding animations are also done by calling _resize_after_modification.

`delete_right(self, parent)`¶

Animates removing the right child of parent. Assumes that parent is in the tree. The check for scaling and the corresponding animations are also done by calling _resize_after_modification.

`delete_left(self, parent)`¶

Animates removing the left child of parent. Assumes that parent is in the tree. The check for scaling and the corresponding animations are also done by calling _resize_after_modification.

`edit_node_value(self, node, text)`¶

Animates updating the value of node to text.

`set_reference_right(self, parent, tree)`¶

Animates setting the reference of the right child of parent to tree. The check for scaling and the corresponding animations are also done by calling _resize_after_modification.

`set_reference_left(self, parent, tree)`¶

Animates setting the reference of the left child of parent to tree. The check for scaling and the corresponding animations are also done by calling _resize_after_modification.

`_resize_after_modification(self, animations)`¶

Check if scaling needs to be done and appends the animation that scales the tree to animations if needed. The check is done by calling check_positioning.

`check_positioning(self)`¶

Checks if the positioning and the size of the tree still fits within the boundary and fully utilises the space; scales the tree (bigger or smaller) if any of the check fails.

`crossing_bottom_border(self)`¶

Computes the scale factor when the tree crosses the bottom boundary.

`crossing_left_right_border(self, offset_x, scale=10e9)`¶

Computes the scle factor if tree crosses the left or right boundary with offset_x added on both sides.

`grow_if_small(self)`¶

Scales the tree bigger if it is not utilising the space allocated fully.

`check_overlapping_children(self, node)`¶

Recursively checks if any of left and right child of node (or its children) are overlapping and scales the tree (or subtree) down if any nodes are overlapping.

Node¶

The Node is the underlying representation of each node constructed as part of a Tree. Therefore, these two classes are put in the same file binary_tree.py.

Constructor¶

The constructor of Node takes in all the arguments as Tree with the same default values. Additionally, it takes in the following:

line_color - the color of the line connecting two nodes together [Optional - defaults to GREEN ]
highlight_color - the color to highlight the node outline in when the node has been accessed [Optional - defaults to YELLOW ]

Inbuilt Functions¶

`set_left(self, node, scale)`¶

Sets the left child of the node to node by calling set_left_mobject. scale represents the scale factor of how much the tree has been scaled (initially starts as 1).

`set_left_mobject(self, shape, vgroup, scale)`¶

Animates setting the left of shape to vgroup - moving vgroup to lower left of shape and adding in the line that connects the two. scale is passed from set_left and used to obtain the position offset from shape.

`set_right(self, node, scale)`¶

Sets the right child of the node to node by calling set_right_mobject. scale represents the scale factor of how much the tree has been scaled (initially starts as 1).

`set_right_mobject(self, shape, vgroup, scale)`¶

Animates setting the right of shape to vgroup - moving vgroup to lower left of shape and adding in the line that connects the two. scale is passed from set_right and used to obtain the position offset from shape.

`set_reference(self, tree, scale, left)`¶

Sets the left or right child of the node to be a reference to tree (in this case a text label) as data structures are passed by reference. The flag left indicates whether the left child or the right child is set. scale represents the scale factor of how much the tree has been scaled (initially starts as 1).

`edit_node_value(self, text)`¶

Changes the text representing the value of the node to text.

`highlight(self, color)`¶

Highlights the node outline to color.

`unhighlight(self)`¶

Unhighlights the node outline.

`set_radius(self, new_radius)`¶

Changes the radius of the node to new_radius and scales the node if needed.

`delete_left(self)`¶

Animates deleting the left child of the node. Assumes that the node has a left child.

`delete_right(self)`¶

Animates deleting the right child of the node. Assumes that the node has a right child.

Code Block¶

The Code Block is your inputted VAlgoLang code which appears at the bottom left of your screen (by default).

The positioning and whether the Code Block should be rendered are controlled by the stylesheet. Please refer to the Customising Your Animation section for a more detailed description of how the stylesheet works.

Constructor¶

The constructor of Code Block takes in the following:

code - list of strings representing each line of code
boundaries - coordinates of boundary that the code block has to stay within
syntax_highlighting - flag indicating whether syntax highlighting of the code is turned on or not
syntax_highlighting_style - the style of syntax highlighting [Optional - defaults to "inkpot" ]
text_color - color of the code [Optional - defaults to WHITE ]
text_weight - weight of the code [Optional - defaults to NORMAL ]
font - font of the code [Optional - defaults to "Times New Roman" ]
tab_spacing - size of tabulation within the code [Optional - defaults to 2 ]

For the full list of possible syntax highlighting style, please refer to the Customising Your Animation section.

Inbuilt Functions¶

`build(self)`¶

Arranges the code block to be correctly formatted and returns the resultant VGroup.

`get_line_at(self, line_number)`¶

Returns the Text of the line of code specified by line_number.

Tracking the line that is currently executing is done with an ArrowTip and the move_arrow_to_line function. If you wish to change that shape, color, or scale, change this line in your construct function.

def construct(self):
    ...
    pointer = ArrowTip(color=YELLOW).scale(0.7).flip(TOP)

Variable Block¶

The Variable Block displays the list of most recently updated variables and their values at the top left of your screen (by default).

The positioning and whether the Variable Block should be rendered are controlled by the stylesheet. Please refer to the Customising Your Animation section for a more detailed description of how the stylesheet works.

Constructor¶

The constructor of Variable Block takes in the following:

variables - list of strings representing the variables and their values
boundaries - coordinates of boundary that the variable block has to stay within
text_color - color of the text [Optional - defaults to WHITE ]
text_weight - weight of the text [Optional - defaults to NORMAL ]
font - font of the text [Optional - defaults to "Times New Roman" ]

Inbuilt Functions¶

`build(self)`¶

Arranges the variable block to be correctly formatted and returns the resultant VGroup.

`update_variable(self, variables)`¶

Animates updating the variable strings with the given argument variables.

Subtitle Block¶

The Subtitle Block displays the list of most recently updated variables and their values at the top left of your screen (by default).

The Subtitle Block holds subtitles generated by the subtitle annotations and the positioning of the Subtitle Block is controlled by the Stlysheet. Please refer to the Subtitles and Customising Your Animation sections for a more detailed description of how the subtitle annotations and stylesheet works.

Constructor¶

The constructor of Variable Block takes in the following:

end_time - time that the subtitle should disappear
boundaries - coordinates of boundary that the subtitle block has to stay within
text_color - color of the subtitle text [Optional - defaults to WHITE ]
text_weight - weight of the subtitle text [Optional - defaults to NORMAL ]
font - font of the subtitle text [Optional - defaults to "Times New Roman" ]

Inbuilt Functions¶

`change_text(self, text)`¶

Changes the subtitle text to text.

`display(self, text, end_time)`¶

Displays the given text as subtitle until the specified end_time has passed.

`clear(self)`¶

Clears the current subtitle.

`action(self)`¶

Same as clear.

Building Blocks¶

The visualisation of data structures is built on top of the following building blocks. Feel free to reuse them if you wish to add your own data structure visualisation!

Initial Structure¶

An initial structure represents the empty state for a data structure, such as for a Stack.

It consists of a line, which can be horizontal or vertical, and a text label indicating the variable name under the line.

Constructor¶

The constructor of Initial Structure takes in the following:

text - text that is labelled under the line
angle - angle of rotation (0 for horizontal line, TAU/4 for vertical line)
length - length for the line [Optional - defaults to 1.5 ]
color - color of the line [Optional - defaults to WHITE ]
text_color - color of the text label [Optional - defaults to WHITE ]
text_weight - weight of the text label [Optional - defaults to NORMAL ]
font - font of the text label [Optional - defaults to "Times New Roman" ]

To add an additional element, create it, and group it with the VGroup. To change the default position of the label and the distance between the label and the line, change DOWN and SMALL_BUFF respectively.

Rectangle Block¶

A Rectangle Block represents a rectangle shape with text inside it.

Constructor¶

The constructor of Rectangle Block takes in the following:

text - text placed inside the rectangle
target - a target that the rectangle block would be scaled to match [Optional - defaults to None ]
width - width of the rectangle [Optional - defaults to 1.5 ]
width - height of the rectangle [Optional - defaults to 0.75 ]
color - color of the rectangle outline [Optional - defaults to BLUE ]
text_color - color of the text inside the rectangle [Optional - defaults to WHITE ]
text_weight - weight of the text inside the rectangle [Optional - defaults to NORMAL ]
font - font of the text inside the rectangle [Optional - defaults to "Times New Roman" ]

To add an additional element, create it, and group it with the VGroup.

Inbuilt Functions¶

`replace_text(self, new_text, color=None)`¶

Animates replacement of the text lablel to new_text inside the rectangle. The optional argument color represents to the new color of the text (defaults to the same as the original text_color).

`clean_up(self)`¶

Cleans up the current Rectangle Block visualisation.

Utility Functions¶

The following is a list of all the utility functions implemented so far, which help to create repeated animation. Feel free to use them if you wish to generate your own animation or contribute!

place_at(self, group, x, y) - places group at the coordinate specified by (x, y, 0).
move_relative_to_edge(self, group, x, y) - moves group relative to the edge specified by (x, y, 0).
move_relative_to_obj(self, group, target, x, y) - moves group relative to the object target specified by (x, y, 0).
place_relative_to_obj(self, group, target, x, y) - places group relative to the object target with the offset specified by (x, y, 0).
fade_out_if_needed(self, mobject) - fades out mobject if it is already on the Scene.
play_animation(self, *args, run_time=1.0) - plays the animation(s) passed in as *args with optional run_time (defaults to 1.0). This is particularly useful as it accounts for all the time_object that have a duration of time they should appear for, such as Subtitle Block.
move_arrow_to_line(self, line_number, pointer, code_block, code_text) - moves the pointer next to the line of code specified by line_number. Scrolling is also handled here if needed by calling the corresponding scroll_down and scroll_up functions.

The following utility functions are inspired from the Manim Reddit community.

scroll_down(self, group, scrolls) - scrolls the group (code_text in the interpreter) down by scrolls number of times.
scroll_up(self, group, scrolls) - scrolls the group (code_text in the interpreter) up by scrolls number of times.

Python Library¶

Data Structure¶

Constructor¶

Inbuilt Functions¶

shrink(self, new_width, new_height)¶

will_cross_boundary(self, object_dim, boundary_name)¶

add(self, obj)¶

Abstract Methods¶

create_init(self, ident)¶

shrink_if_cross_boundary(self, obj)¶

clean_up(self)¶

Stack¶

Constructor¶

Inbuilt Functions¶

push(self, obj, creation_style=None)¶

push_existing(self, obj)¶

pop(self, obj, fade_out=True)¶

Array (1D)¶

Constructor¶

Inbuilt Functions¶

build(self, coord=None)¶

swap_mobjects(self, i1, i2)¶

clone_and_swap(self, i1, i2)¶

update_element(self, idx, v, color=None)¶

update_array_elements(self)¶

append(self, v)¶

Array 2D¶

Constructor¶

Inbuilt Functions¶

build(self, creation_style=None)¶

replace_row(self, row_index, new_values)¶

swap_mobjects(self, i1, j1, i2, j2)¶

Tree¶

Constructor¶

Inbuilt Functions¶

update_root(self, node)¶

check_if_child_will_cross_boundary(self, parent, child, is_left)¶

set_right(self, parent, child)¶

set_left(self, parent, child)¶

delete_right(self, parent)¶

delete_left(self, parent)¶

edit_node_value(self, node, text)¶

set_reference_right(self, parent, tree)¶

set_reference_left(self, parent, tree)¶

_resize_after_modification(self, animations)¶

check_positioning(self)¶

crossing_bottom_border(self)¶

crossing_left_right_border(self, offset_x, scale=10e9)¶

grow_if_small(self)¶

check_overlapping_children(self, node)¶

Node¶

Constructor¶

Inbuilt Functions¶

set_left(self, node, scale)¶

set_left_mobject(self, shape, vgroup, scale)¶

set_right(self, node, scale)¶

set_right_mobject(self, shape, vgroup, scale)¶

set_reference(self, tree, scale, left)¶

edit_node_value(self, text)¶

highlight(self, color)¶

unhighlight(self)¶

set_radius(self, new_radius)¶

delete_left(self)¶

delete_right(self)¶

Code Block¶

Constructor¶

Inbuilt Functions¶

build(self)¶

get_line_at(self, line_number)¶

Variable Block¶

Constructor¶

Inbuilt Functions¶

build(self)¶

update_variable(self, variables)¶

Subtitle Block¶

Constructor¶

Inbuilt Functions¶

change_text(self, text)¶

display(self, text, end_time)¶

clear(self)¶

`shrink(self, new_width, new_height)`¶

`will_cross_boundary(self, object_dim, boundary_name)`¶

`add(self, obj)`¶

`create_init(self, ident)`¶

`shrink_if_cross_boundary(self, obj)`¶

`clean_up(self)`¶

`push(self, obj, creation_style=None)`¶

`push_existing(self, obj)`¶

`pop(self, obj, fade_out=True)`¶

`build(self, coord=None)`¶

`swap_mobjects(self, i1, i2)`¶

`clone_and_swap(self, i1, i2)`¶

`update_element(self, idx, v, color=None)`¶

`update_array_elements(self)`¶

`append(self, v)`¶

`build(self, creation_style=None)`¶

`replace_row(self, row_index, new_values)`¶

`swap_mobjects(self, i1, j1, i2, j2)`¶

`update_root(self, node)`¶

`check_if_child_will_cross_boundary(self, parent, child, is_left)`¶

`set_right(self, parent, child)`¶

`set_left(self, parent, child)`¶

`delete_right(self, parent)`¶

`delete_left(self, parent)`¶

`edit_node_value(self, node, text)`¶

`set_reference_right(self, parent, tree)`¶

`set_reference_left(self, parent, tree)`¶

`_resize_after_modification(self, animations)`¶

`check_positioning(self)`¶

`crossing_bottom_border(self)`¶

`crossing_left_right_border(self, offset_x, scale=10e9)`¶

`grow_if_small(self)`¶

`check_overlapping_children(self, node)`¶

`set_left(self, node, scale)`¶

`set_left_mobject(self, shape, vgroup, scale)`¶

`set_right(self, node, scale)`¶

`set_right_mobject(self, shape, vgroup, scale)`¶

`set_reference(self, tree, scale, left)`¶

`edit_node_value(self, text)`¶

`highlight(self, color)`¶

`unhighlight(self)`¶

`set_radius(self, new_radius)`¶

`delete_left(self)`¶

`delete_right(self)`¶

`build(self)`¶

`get_line_at(self, line_number)`¶

`build(self)`¶

`update_variable(self, variables)`¶

`change_text(self, text)`¶

`display(self, text, end_time)`¶

`clear(self)`¶

`action(self)`¶

`replace_text(self, new_text, color=None)`¶

`clean_up(self)`¶