Positions ------------ .. note:: :underbold:`Source code of this section`: `_03_basic_positions.py `_ For this section we will be using the object called ScreenGrid, a Mobject that I created to help us visualize the coordinates of the screen. .. code-block:: python class CoordScreen(Scene): def construct(self): screen_grid = ScreenGrid() dot = Dot([1, 1, 0]) self.add(screen_grid) self.play(FadeIn(dot)) self.wait() .. image:: ../_static/CoordScreen.png There are several constants that help to locate objects on the screen, and we can specify any coordinate through them using linear combinations. From ``manim/constants.py`` .. code-block:: python # Geometry: directions ORIGIN: np.ndarray = np.array((0.0, 0.0, 0.0)) """The center of the coordinate system.""" UP: np.ndarray = np.array((0.0, 1.0, 0.0)) """One unit step in the positive Y direction.""" DOWN: np.ndarray = np.array((0.0, -1.0, 0.0)) """One unit step in the negative Y direction.""" RIGHT: np.ndarray = np.array((1.0, 0.0, 0.0)) """One unit step in the positive X direction.""" LEFT: np.ndarray = np.array((-1.0, 0.0, 0.0)) """One unit step in the negative X direction.""" IN: np.ndarray = np.array((0.0, 0.0, -1.0)) """One unit step in the negative Z direction.""" OUT: np.ndarray = np.array((0.0, 0.0, 1.0)) """One unit step in the positive Z direction.""" # Geometry: axes X_AXIS: np.ndarray = np.array((1.0, 0.0, 0.0)) Y_AXIS: np.ndarray = np.array((0.0, 1.0, 0.0)) Z_AXIS: np.ndarray = np.array((0.0, 0.0, 1.0)) # Geometry: useful abbreviations for diagonals UL: np.ndarray = UP + LEFT """One step up plus one step left.""" UR: np.ndarray = UP + RIGHT """One step up plus one step right.""" DL: np.ndarray = DOWN + LEFT """One step down plus one step left.""" DR: np.ndarray = DOWN + RIGHT """One step down plus one step right.""" Example: .. code-block:: python class BasicPositions(Scene): def construct(self): dot_center = Dot(color=WHITE) # ORIGIN: [0,0,0] by default dot_left = Dot(LEFT,color=RED) # [-1,0,0] dot_right = Dot(RIGHT,color=BLUE) # [1,0,0] dot_up = Dot(UP,color=GREEN) # [0,1,0] dot_down = Dot(DOWN,color=ORANGE) # [0,-1,0] dot_2_3 = Dot([2,3,0],color=TEAL)# [2,3,0] logger.info(f"frame_width: {config.frame_width}") logger.info(f"frame_height: {config.frame_height}") self.add( # ScreenGrid(), # <- uncomment this dot_center, dot_left, dot_right, dot_up, dot_down, dot_2_3, ) self.wait() .. image:: ../_static/BasicPositions.png ``Mobject.to_edge & Mobject.to_corner`` """""""""""""""""""""""""""""""""""""""""" .. code-block:: python class EdgesAndCorners(Scene): def construct(self): square = Square() square.to_corner(UR) # UP + RIGHT triangle = Triangle() triangle.to_edge(DOWN,buff=0.1) # DOWN + LEFT dot_up = Dot(color=RED) dot_up.to_edge(UP) dot_down = Dot(color=BLUE) dot_down.to_edge(DOWN,buff=2) self.add( square, triangle, dot_up, dot_down ) self.wait() .. image:: ../_static/EdgesAndCorners.png ``Mobject.shift`` """""""""""""""""" .. code-block:: python class ShiftMethod(Scene): """ The shift method moves the object based on the current position of the object. """ def construct(self): circle = Circle() self.add(circle) self.wait() circle.shift(RIGHT) self.wait() circle.shift(RIGHT) self.wait() circle.shift(DOWN) self.wait() circle.shift(LEFT) self.wait() .. raw:: html
``Mobject.move_to`` """"""""""""""""""""" .. code-block:: python class MoveToMethod1(Scene): """ The move_to method moves the object taking as reference the origin or some particular point """ def construct(self): circle = Circle() self.add(circle) self.wait() # In this way, it takes the center of the screen as a reference circle.move_to(RIGHT) self.wait() circle.move_to(RIGHT) self.wait() circle.move_to(DOWN) self.wait() circle.move_to([2,3,0]) self.wait() .. raw:: html
.. code-block:: python class MoveToMethod2(Scene): def construct(self): circle = Circle() dot_1 = Dot([1,3,0],color=ORANGE) dot_2 = Dot([-2,-3,0],color=BLUE) self.add(circle,dot_1,dot_2) self.wait() circle.move_to(dot_1) self.wait() circle.move_to(dot_2) self.wait() In this way, it takes a Mobject (dot_2) as a reference circle.move_to(dot_2.get_center()+RIGHT) self.wait() .. raw:: html
``Mobject.next_to`` """"""""""""""""""""" .. code-block:: python class NextTo(Scene): """ next_to references the edges of an object to locate another object. """ def construct(self): text = Text("Hello world") text.shift(LEFT+2*UP) left_dot = Dot().next_to(text,LEFT) right_dot = Dot().next_to(text,RIGHT,buff=0) down_dot = Dot().next_to(text,DOWN,buff=1) self.add(text, left_dot, right_dot,down_dot) self.wait() .. image:: ../_static/NextTo.png ``Mobject.get_`` """"""""""""""""" .. code-block:: python class BordersAndCorners(Scene): def construct(self): text = Text("Hello world").scale(2) d1 = Dot(text.get_corner(UL)) d2 = Dot(text.get_bottom()) d3 = Dot(text.get_top()) d4 = Dot(text.get_left()) d5 = Dot(text.get_right()) self.add(text,d1,d2,d3,d4,d5) self.wait() .. image:: ../_static/BordersAndCorners.png In addition to these methods there are also these others: * ``Mobject.get_x()`` :math:`\Leftrightarrow` ``Mobject.get_center()[0]`` * ``Mobject.get_y()`` :math:`\Leftrightarrow` ``Mobject.get_center()[1]`` * ``Mobject.get_z()`` :math:`\Leftrightarrow` ``Mobject.get_center()[2]`` ``Mobject.align_to`` """"""""""""""""""""""" .. code-block:: python class Align(Scene): def construct(self): rect = Rectangle(width=6,height=4,color=RED) a = Text("A") b = Text("B") c = Text("C") a.align_to(rect,LEFT) b.align_to(rect,UP) c.align_to(rect,UR) self.add(rect,a,b,c) self.wait() .. image:: ../_static/Align.png ``Mobject.rotate`` """"""""""""""""""" .. code-block:: python class Rotations(Scene): def construct(self): a = Text("A") a.shift(LEFT*3) a.rotate(30*DEGREES) #or .rotate(PI/6) dot = Dot(RIGHT) b = Text("B") b.rotate(PI/2,about_point=dot.get_center()) self.add(a,b,dot) self.wait() .. image:: ../_static/Rotations.png