How to get_lines from point to point in manim?

Question

When I try to get_horizontal_line from one dot to another it goes from the y-axes. I want that the dashedline comes from the point [1;1] to point [3;1]. Because now it comes from [0;1] to[3;1]directly from the axis coordinate.

I don't know how to get lines not from the axis but from the point. Also here is my code:

from manim import *

class KvadratickaFunkcia(Scene):
    def construct(self):

        suradnicovaOs = Axes(                                                                
            x_range=[-8,8,1],
            y_range=[-8,8,1],
            tips=False,
            x_length=10,
            y_length=10,

            axis_config=
            {
            "stroke_color": GREY_A,
            "include_numbers": True,
            }
        )

       
        #vzorec  x-2
        posunParabolyVzorecMinus2a = MathTex("{y = (x-2)^2+0}", font_size=50).to_edge(UL).set_color(YELLOW)
        posunParabolyVzorecMinus2a[0][5].set_color(RED)
        posunParabolyVzorecMinus2a[0][9].set_color(RED)
        #vzorec parabola y: (y-2)**2+0
        parabolaMinus2a = suradnicovaOs.plot(lambda y: (y-2)**2+0 )
        #body 1,2,3
        bodMinus2a= Dot(suradnicovaOs.coords_to_point(1, 1), color=YELLOW)
        bodkociarkaMinus2a = suradnicovaOs.get_horizontal_line(suradnicovaOs.c2p(3,1))
        bodMinus2a2 = Dot(suradnicovaOs.coords_to_point(2, 0), color=YELLOW)
        bodkociarkaMinus2a2 = suradnicovaOs.get_vertical_line(suradnicovaOs.c2p(1,1))
        bodMinus2a3 = Dot(suradnicovaOs.coords_to_point(3, 1), color=YELLOW)
        bodkociarkaMinus2a3 = suradnicovaOs.get_vertical_line(suradnicovaOs.c2p(3,1))
        VsetkyBodyMinus123AA = VGroup(bodMinus2a,bodMinus2a2,bodMinus2a3,bodkociarkaMinus2a,bodkociarkaMinus2a2,bodkociarkaMinus2a3)

        self.play(Write(suradnicovaOs), run_time=3)
        self.play(Create(posunParabolyVzorecMinus2a))
        self.play(Create(VsetkyBodyMinus123AA))   
        self.wait()
        self.play(FadeIn(parabolaMinus2a))

image of my problem:

score 0 · Answer 1 · answered Jan 20 '23 at 22:08

Welcome to the SO! You can use the .get_center() functions of the two points and connect them via DashedLine with stroke_width of 2. You should ignore bodkociarkaMinus2a and use the following line:

my_line: DashedLine = DashedLine(
    bodMinus2a.get_center(), bodMinus2a3.get_center(),stroke_width = 2
)

Here is the full code:

from manim import *

class KvadratickaFunkcia(Scene):
    def construct(self):

        suradnicovaOs = Axes(                                                                
            x_range=[-8,8,1],
            y_range=[-8,8,1],
            tips=False,
            x_length=10,
            y_length=10,

            axis_config=
            {
            "stroke_color": GREY_A,
            "include_numbers": True,
            }
        )

        #vzorec  x-2
        posunParabolyVzorecMinus2a = MathTex("{y = (x-2)^2+0}", font_size=50).to_edge(UL).set_color(YELLOW)
        posunParabolyVzorecMinus2a[0][5].set_color(RED)
        posunParabolyVzorecMinus2a[0][9].set_color(RED)
        #vzorec parabola y: (y-2)**2+0
        parabolaMinus2a = suradnicovaOs.plot(lambda y: (y-2)**2+0 )
        #body 1,2,3
        bodMinus2a= Dot(suradnicovaOs.coords_to_point(1, 1), color=YELLOW)
        #bodkociarkaMinus2a = suradnicovaOs.get_horizontal_line(suradnicovaOs.c2p(3,1))
        bodMinus2a2 = Dot(suradnicovaOs.coords_to_point(2, 0), color=YELLOW)
        bodkociarkaMinus2a2 = suradnicovaOs.get_vertical_line(suradnicovaOs.c2p(1,1))
        bodMinus2a3 = Dot(suradnicovaOs.coords_to_point(3, 1), color=YELLOW)
        bodkociarkaMinus2a3 = suradnicovaOs.get_vertical_line(suradnicovaOs.c2p(3,1))
        my_line: DashedLine = DashedLine(
            bodMinus2a.get_center(), bodMinus2a3.get_center(),stroke_width = 2
        )
        VsetkyBodyMinus123AA = VGroup(bodMinus2a,bodMinus2a2,bodMinus2a3, my_line, bodkociarkaMinus2a2, bodkociarkaMinus2a3)

        self.play(Write(suradnicovaOs), run_time=3)
        self.play(Create(posunParabolyVzorecMinus2a))
        self.play(Create(VsetkyBodyMinus123AA))   
        self.wait()
        self.play(FadeIn(parabolaMinus2a))

How to get_lines from point to point in manim?

1 Answers1