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Learning by Example
===================
You create videos in manim by writing :class:`~scene.scene.Scene` instances.
``example_scenes.py`` contains a few simple ones that we can use to learn about
manim. For instance, take ``SquareToCircle``.
SquareToCircle
--------------
``example_scenes.py`` contains simple examples that we can use to learn about manim.
Go ahead and try out the ``SquareToCircle`` scene by running it with ``$ manim example_scenes.py SquareToCircle -p``
in manim directory.
.. code-block:: python
:linenos:
from manimlib.imports import *
class SquareToCircle(Scene):
def construct(self):
circle = Circle()
@ -20,115 +26,106 @@ manim. For instance, take ``SquareToCircle``.
self.play(Transform(square, circle))
self.play(FadeOut(square))
:meth:`~scene.scene.Scene.construct` specifies what is displayed on the screen
when the :class:`~scene.scene.Scene` is rendered to video. You can render a
:class:`~scene.scene.Scene` by running ``extract_scene.py``. Run ``python
extract_scene.py -h`` to see how it's used.
.. code-block:: none
> python extract_scene.py -h
usage: extract_scene.py [-h] [-p] [-w] [-s] [-l] [-m] [-g] [-f] [-t] [-q] [-a]
[-o OUTPUT_NAME] [-n START_AT_ANIMATION_NUMBER]
[-r RESOLUTION] [-c COLOR] [-d OUTPUT_DIRECTORY]
file [scene_name]
positional arguments:
file path to file holding the python code for the scene
scene_name Name of the Scene class you want to see
optional arguments:
-h, --help show this help message and exit
-p, --preview
-w, --write_to_movie
-s, --show_last_frame
-l, --low_quality
-m, --medium_quality
-g, --save_pngs
-f, --show_file_in_finder
-t, --transparent
-q, --quiet
-a, --write_all
-o OUTPUT_NAME, --output_name OUTPUT_NAME
-n START_AT_ANIMATION_NUMBER, --start_at_animation_number START_AT_ANIMATION_NUMBER
-r RESOLUTION, --resolution RESOLUTION
-c COLOR, --color COLOR
-d OUTPUT_DIRECTORY, --output_directory OUTPUT_DIRECTORY
The most common flags are ``-p``, to automatically play the generated video,
``-l``, to render in lower quality in favor of speed, and ``-s``, to show the
last frame of the :class:`~scene.scene.Scene` for faster development. Run
``python extract_scene.py example_scenes.py SquareToCircle -pl`` to produce a
file called SquareToCircle.mp4 in the media directory that you have configured,
and automatically play it.
.. raw:: html
<video width="560" height="315" controls>
<source src="../_static/SquareToCircle.mp4" type="video/mp4">
</video>
<video width="560" height="315" controls>
<source src="../_static/SquareToCircle.mp4" type="video/mp4">
</video>
Let's step through each line of the :class:`~scene.scene.Scene`. Lines 3 and 4
instantiate a :class:`~mobject.geometry.Circle` and
:class:`~mobject.geometry.Square`, respectively. Both of these subclass
:class:`~mobject.mobject.Mobject`, the base class for objects in manim. Note
.. note::
The flag ``-p`` plays the rendered video with default video player.
Other frequently used flags are:
* ``-l`` for rendering video in lower resolution (which renders faster)
* ``-s`` to show the last frame of the video.
Run ``manim -h`` all the available flags (``python -m manim -h`` if you installed it to a venv)
Let's step through each line of ``SquareToCircle``
.. code-block:: python
:lineno-start: 3
class SquareToCircle(Scene):
You create videos in manim by writing :class:`~scene.scene.Scene` classes.
Each :class:`~scene.scene.Scene` in manim is self-contained. That means everything
you created under this scene does not exist outside the class.
.. code-block:: python
:lineno-start: 4
def construct(self):
:meth:`~scene.scene.Scene.construct` specifies what is displayed on the screen
when the :class:`~scene.scene.Scene` is rendered to video.
.. code-block:: python
:lineno-start: 5
circle = Circle()
square = Square()
``Circle()`` and ``Square()`` create :class:`~mobject.geometry.Circle` and :class:`~mobject.geometry.Square`.
Both of these are instances of :class:`~mobject.mobject.Mobject` subclasses, the base class for objects in manim. Note
that instantiating a :class:`~mobject.mobject.Mobject` does not add it to the
:class:`~scene.scene.Scene`, so you wouldn't see anything if you were to render
the :class:`~scene.scene.Scene` at this point.
.. code-block:: python
:linenos:
:lineno-start: 3
circle = Circle()
square = Square()
Lines 5, 6, and 7 apply various modifications to the mobjects before animating
them. The call to :meth:`~mobject.mobject.Mobject.flip` on line 5 flips the
:class:`~mobject.geometry.Square` across the RIGHT vector. This is equivalent
to a refection across the x-axis. Then the call to
:meth:`~mobject.mobject.Mobject.rotate` on line 6 rotates the
:class:`~mobject.geometry.Square` 3/8ths of a full rotation counterclockwise.
Finally, the call to :meth:`~mobject.mobject.Mobject.set_fill` on line 7 sets
the fill color for the :class:`~mobject.geometry.Circle` to pink, and its
opacity to 0.5.
.. code-block:: python
:linenos:
:lineno-start: 5
:lineno-start: 7
square.flip(RIGHT)
square.rotate(-3 * TAU / 8)
circle.set_fill(PINK, opacity=0.5)
Line 9 is the first to generate video.
:class:`~animation.creation.ShowCreation`,
:class:`~animation.transform.Transform`, and
:class:`~animation.creation.FadeOut` are
:class:`~animation.animation.Animation` instances. Each
:class:`~animation.animation.Animation` takes one or more
:class:`~mobject.mobject.Mobject` instances as arguments, which it animates
when passed to :meth:`~scene.scene.Scene.play`. This is how video is typically
created in manim. :class:`~mobject.mobject.Mobject` instances are automatically
added to the :class:`~scene.scene.Scene` when they are animated. You can add a
:class:`~mobject.mobject.Mobject` to the :class:`~scene.scene.Scene` manually
by passing it as an argument to :meth:`~scene.scene.Scene.add`.
``flip()`` ``rotate()`` ``set_fill()`` apply various modifications to the mobjects before animating
them. The call to :meth:`~mobject.mobject.Mobject.flip` flips the
:class:`~mobject.geometry.Square` across the RIGHT vector. This is equivalent
to a refection across the x-axis.
The call to :meth:`~mobject.mobject.Mobject.rotate` rotates the
:class:`~mobject.geometry.Square` 3/8ths of a full rotation counterclockwise.
The call to :meth:`~mobject.mobject.Mobject.set_fill` sets
the fill color for the :class:`~mobject.geometry.Circle` to pink, and its opacity to 0.5.
.. code-block:: python
:linenos:
:lineno-start: 9
:lineno-start: 11
self.play(ShowCreation(square))
self.play(Transform(square, circle))
self.play(FadeOut(square))
:class:`~animation.creation.ShowCreation` draws a
:class:`~mobject.mobject.Mobject` to the screen,
:class:`~animation.transform.Transform` morphs one
:class:`~mobject.mobject.Mobject` into another, and
:class:`~animation.creation.FadeOut` fades a
:class:`~mobject.mobject.Mobject` out of the :class:`~scene.scene.Scene`. Note
that only the first argument to :class:`~animation.transform.Transform` is
modified, and the second is not added to the :class:`~scene.scene.Scene`. After
line 10 is executed ``square`` is a :class:`~mobject.geometry.Square` instance
with the shape of a :class:`~mobject.geometry.Circle`.
To generated animation, :class:`~animation.animation.Animation` classes are used.
Each :class:`~animation.animation.Animation` takes one or more :class:`~mobject.mobject.Mobject` instances as arguments, which it animates
when passed to :meth:`~scene.scene.Scene.play`. This is how video is typically
created in manim.
:class:`~mobject.mobject.Mobject` instances are automatically
added to the :class:`~scene.scene.Scene` when they are animated. You can add a
:class:`~mobject.mobject.Mobject` to the :class:`~scene.scene.Scene` manually
by passing it as an argument to :meth:`~scene.scene.Scene.add`.
:class:`~animation.creation.ShowCreation` draws a :class:`~mobject.mobject.Mobject` to the screen.
:class:`~animation.transform.Transform` morphs one :class:`~mobject.mobject.Mobject` into another.
:class:`~animation.creation.FadeOut` fades a :class:`~mobject.mobject.Mobject` out of the :class:`~scene.scene.Scene`.
.. note::
Only the first argument to :class:`~animation.transform.Transform` is modified,
the second is not added to the :class:`~scene.scene.Scene`. :class:`~animation.tranform.Transform`
only changes the appearance but not the underlying properties.
After the call to ``transform()`` ``square`` is still a :class:`~mobject.geometry.Square` instance
but with the shape of :class:`~mobject.geometry.Circle`.

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Mac
===
A stub for mac installation
The simplest way to install the system dependencies on Mac OS X is with Homebrew.
Mac come preinstalled with python2, but to use manim, python3 is required
1. Install python3 https://docs.python.org/3/using/mac.html
2. Install Cairo: ``brew install cairo``
3. Install Sox: ``brew install sox``
4. Install ffmpeg: ``brew install ffmpeg``
5. Install latex (MiKTeX): https://miktex.org/howto/install-miktex-mac
6. Install manimlib ``pip install manimlib`` (or ``pip install --user manimlib`` to just yourself)