class WhatIsCONFIG (Scene ):
CONFIG = {
"object_1" :TextMobject ("Object 1" ),
"object_2" :Square (),
"number" :3 ,
"vector" :[1 ,1 ,0 ]
}
def construct (self ):
self .play (
Write (self .object_1 )
)
self .play (
self .object_1 .scale ,self .number
)
self .play (
ReplacementTransform (
self .object_1 ,
self .object_2
)
)
self .play (
self .object_2 .shift ,self .vector
)
self .wait ()
class SceneFromAnotherScene (WhatIsCONFIG ):
CONFIG = {
"object_1" :TextMobject ("Another object" ),
"object_2" :Circle (),
"number" :4 ,
"vector" :[- 1 ,- 1 ,0 ]
}
class ChangeBackgroundColor (Scene ):
CONFIG = {
"camera_config" :{"background_color" :RED },
"text" :TexMobject (r"\frac{d}{dx}\Bigr|_{y=2}" ).scale (5 )
}
def construct (self ):
self .add (self .text )Remove background stroke width of texts
class RemoveBackgroundStrokeWidth (ChangeBackgroundColor ):
CONFIG = {
"text" :TexMobject (
r"\frac{d}{dx}\Bigr|_{y=2}" ,
background_stroke_width = 0 , #<- Add this line
).scale (5 )
}
class ArrangeObjects (Scene ):
def construct (self ):
text1 = TextMobject ("You have" )
text2 = TextMobject ("to use" )
text3 = TextMobject ("\\ tt VGroup" )
text_group = VGroup (
text1 ,
text2 ,
text3
)
# .arrange # <- For recent versions
text_group .arrange_submobjects (
DOWN , # <- Direction
aligned_edge = LEFT ,
buff = 0.4
)
self .add (text_group )
self .wait ()
self .play (
text_group .arrange_submobjects ,UP ,{"aligned_edge" :RIGHT ,"buff" :2 }
)
self .wait ()
self .play (
text_group .arrange_submobjects ,RIGHT ,{"buff" :0.4 }
)
self .wait ()Change position and size of the camera
class ChangePositionAndSizeCamera (MovingCameraScene ):
def construct (self ):
text = TexMobject ("\\ nabla\\ textbf{u}" ).scale (3 )
square = Square ()
# Arrange the objects
VGroup (text ,square ).arrange_submobjects (RIGHT ,buff = 3 )
self .add (text ,square )
# Save the state of camera
self .camera_frame .save_state ()
# Animation of the camera
self .play (
# Set the size with the width of a object
self .camera_frame .set_width ,text .get_width ()* 1.2 ,
# Move the camera to the object
self .camera_frame .move_to ,text
)
self .wait ()
# Restore the state saved
self .play (Restore (self .camera_frame ))
self .play (
self .camera_frame .set_height ,square .get_width ()* 1.2 ,
self .camera_frame .move_to ,square
)
self .wait ()
self .play (Restore (self .camera_frame ))
self .wait ()Change position and size of the camera in other scenes
class ChangePositionAndSizeCameraInAnotherScene (GraphScene ,MovingCameraScene ):
CONFIG = {
"y_max" : 50 ,
"y_min" : 0 ,
"x_max" : 7 ,
"x_min" : 0 ,
"y_tick_frequency" : 5 ,
"x_tick_frequency" : 0.5 ,
}
# Setup the scenes
def setup (self ):
GraphScene .setup (self )
MovingCameraScene .setup (self )
def construct (self ):
self .setup_axes (animate = False )
graph = self .get_graph (lambda x : x ** 2 ,
color = GREEN ,
x_min = 0 ,
x_max = 7
)
dot_at_start_graph = Dot ().move_to (graph .points [0 ])
dot_at_end_grap = Dot ().move_to (graph .points [- 1 ])
self .add (graph ,dot_at_end_grap ,dot_at_start_graph )
self .play (
self .camera_frame .scale ,.5 ,
self .camera_frame .move_to ,dot_at_start_graph
)
self .play (
self .camera_frame .move_to ,dot_at_end_grap
)
self .wait ()
class LinearTransformation (LinearTransformationScene ):
CONFIG = {
"include_background_plane" : True ,
"include_foreground_plane" : True ,
"foreground_plane_kwargs" : {
"x_radius" : FRAME_WIDTH ,
"y_radius" : FRAME_HEIGHT ,
"secondary_line_ratio" : 0
},
"background_plane_kwargs" : {
"color" : GREY ,
"secondary_color" : DARK_GREY ,
"axes_color" : GREY ,
"stroke_width" : 2 ,
},
"show_coordinates" : False ,
"show_basis_vectors" : True ,
"basis_vector_stroke_width" : 6 ,
"i_hat_color" : X_COLOR ,
"j_hat_color" : Y_COLOR ,
"leave_ghost_vectors" : False ,
}
def construct (self ):
mob = Circle ()
mob .move_to (RIGHT + UP * 2 )
vector_array = np .array ([[1 ], [2 ]])
matrix = [[0 , 1 ], [- 1 , 1 ]]
self .add_transformable_mobject (mob )
self .add_vector (vector_array )
self .apply_matrix (matrix )
self .wait ()Remove all objects in screen
class RemoveAllObjectsInScreen (Scene ):
def construct (self ):
self .add (
VGroup (
* [
VGroup (
* [
Dot ()
for i in range (30 )
]
).arrange_submobjects (RIGHT )
for j in range (10 )
]
).arrange_submobjects (DOWN )
)
self .play (
* [FadeOut (mob )for mob in self .mobjects ]
# All mobjects in the screen are saved in self.mobjects
)
self .wait ()
class ZoomedSceneExample (ZoomedScene ):
CONFIG = {
"zoom_factor" : 0.3 ,
"zoomed_display_height" : 1 ,
"zoomed_display_width" : 6 ,
"image_frame_stroke_width" : 20 ,
"zoomed_camera_config" : {
"default_frame_stroke_width" : 3 ,
},
}
def construct (self ):
# Set objects
dot = Dot ().shift (UL * 2 )
image = ImageMobject (np .uint8 ([[ 0 , 100 ,30 , 200 ],
[255 ,0 ,5 , 33 ]]))
image .set_height (7 )
frame_text = TextMobject ("Frame" ,color = PURPLE ).scale (1.4 )
zoomed_camera_text = TextMobject ("Zommed camera" ,color = RED ).scale (1.4 )
self .add (image ,dot )
# Set camera
zoomed_camera = self .zoomed_camera
zoomed_display = self .zoomed_display
frame = zoomed_camera .frame
zoomed_display_frame = zoomed_display .display_frame
frame .move_to (dot )
frame .set_color (PURPLE )
zoomed_display_frame .set_color (RED )
zoomed_display .shift (DOWN )
# brackground zoomed_display
zd_rect = BackgroundRectangle (
zoomed_display ,
fill_opacity = 0 ,
buff = MED_SMALL_BUFF ,
)
self .add_foreground_mobject (zd_rect )
# animation of unfold camera
unfold_camera = UpdateFromFunc (
zd_rect ,
lambda rect : rect .replace (zoomed_display )
)
frame_text .next_to (frame ,DOWN )
self .play (
ShowCreation (frame ),
FadeInFromDown (frame_text )
)
# Activate zooming
self .activate_zooming ()
self .play (
# You have to add this line
self .get_zoomed_display_pop_out_animation (),
unfold_camera
)
zoomed_camera_text .next_to (zoomed_display_frame ,DOWN )
self .play (FadeInFromDown (zoomed_camera_text ))
# Scale in x y z
scale_factor = [0.5 ,1.5 ,0 ]
# Resize the frame and zoomed camera
self .play (
frame .scale , scale_factor ,
zoomed_display .scale , scale_factor ,
FadeOut (zoomed_camera_text ),
FadeOut (frame_text )
)
# Resize the frame
self .play (
frame .scale ,3 ,
frame .shift ,2.5 * DOWN
)
# Resize zoomed camera
self .play (
ScaleInPlace (zoomed_display ,2 )
)
self .wait ()
self .play (
self .get_zoomed_display_pop_out_animation (),
unfold_camera ,
# -------> Inverse
rate_func = lambda t : smooth (1 - t ),
)
self .play (
Uncreate (zoomed_display_frame ),
FadeOut (frame ),
)
self .wait () 
