Source code for manim.mobject.svg.brace

"""Mobject representing curly braces."""

from __future__ import annotations

__all__ = ["Brace", "BraceLabel", "ArcBrace", "BraceText", "BraceBetweenPoints"]

from typing import Sequence

import numpy as np
import svgelements as se

from manim._config import config
from manim.mobject.geometry.arc import Arc
from manim.mobject.geometry.line import Line
from manim.mobject.mobject import Mobject
from manim.mobject.opengl.opengl_compatibility import ConvertToOpenGL
from manim.mobject.text.tex_mobject import MathTex, Tex

from ...animation.composition import AnimationGroup
from ...animation.fading import FadeIn
from ...animation.growing import GrowFromCenter
from ...constants import *
from ...mobject.types.vectorized_mobject import VMobject
from ...utils.color import BLACK
from ..svg.svg_mobject import VMobjectFromSVGPath

[docs]class Brace(VMobjectFromSVGPath): """Takes a mobject and draws a brace adjacent to it. Passing a direction vector determines the direction from which the brace is drawn. By default it is drawn from below. Parameters ---------- mobject The mobject adjacent to which the brace is placed. direction : The direction from which the brace faces the mobject. See Also -------- :class:`BraceBetweenPoints` Examples -------- .. manim:: BraceExample :save_last_frame: class BraceExample(Scene): def construct(self): s = Square() self.add(s) for i in np.linspace(0.1,1.0,4): br = Brace(s, sharpness=i) t = Text(f"sharpness= {i}").next_to(br, RIGHT) self.add(t) self.add(br) VGroup(*self.mobjects).arrange(DOWN, buff=0.2) """ def __init__( self, mobject: Mobject, direction: Sequence[float] | None = DOWN, buff=0.2, sharpness=2, stroke_width=0, fill_opacity=1.0, background_stroke_width=0, background_stroke_color=BLACK, **kwargs, ): path_string_template = ( "m0.01216 0c-0.01152 0-0.01216 6.103e-4 -0.01216 0.01311v0.007762c0.06776 " "0.122 0.1799 0.1455 0.2307 0.1455h{0}c0.03046 3.899e-4 0.07964 0.00449 " "0.1246 0.02636 0.0537 0.02695 0.07418 0.05816 0.08648 0.07769 0.001562 " "0.002538 0.004539 0.002563 0.01098 0.002563 0.006444-2e-8 0.009421-2.47e-" "5 0.01098-0.002563 0.0123-0.01953 0.03278-0.05074 0.08648-0.07769 0.04491" "-0.02187 0.09409-0.02597 0.1246-0.02636h{0}c0.05077 0 0.1629-0.02346 " "0.2307-0.1455v-0.007762c-1.78e-6 -0.0125-6.365e-4 -0.01311-0.01216-0.0131" "1-0.006444-3.919e-8 -0.009348 2.448e-5 -0.01091 0.002563-0.0123 0.01953-" "0.03278 0.05074-0.08648 0.07769-0.04491 0.02187-0.09416 0.02597-0.1246 " "0.02636h{1}c-0.04786 0-0.1502 0.02094-0.2185 0.1256-0.06833-0.1046-0.1706" "-0.1256-0.2185-0.1256h{1}c-0.03046-3.899e-4 -0.07972-0.004491-0.1246-0.02" "636-0.0537-0.02695-0.07418-0.05816-0.08648-0.07769-0.001562-0.002538-" "0.004467-0.002563-0.01091-0.002563z" ) default_min_width = 0.90552 self.buff = buff angle = -np.arctan2(*direction[:2]) + np.pi mobject.rotate(-angle, about_point=ORIGIN) left = mobject.get_corner(DOWN + LEFT) right = mobject.get_corner(DOWN + RIGHT) target_width = right[0] - left[0] linear_section_length = max( 0, (target_width * sharpness - default_min_width) / 2, ) path = se.Path( path_string_template.format( linear_section_length, -linear_section_length, ) ) super().__init__( path_obj=path, stroke_width=stroke_width, fill_opacity=fill_opacity, background_stroke_width=background_stroke_width, background_stroke_color=background_stroke_color, **kwargs, ) self.flip(RIGHT) self.stretch_to_fit_width(target_width) self.shift(left - self.get_corner(UP + LEFT) + self.buff * DOWN) for mob in mobject, self: mob.rotate(angle, about_point=ORIGIN) def put_at_tip(self, mob, use_next_to=True, **kwargs): if use_next_to: mob.next_to(self.get_tip(), np.round(self.get_direction()), **kwargs) else: mob.move_to(self.get_tip()) buff = kwargs.get("buff", DEFAULT_MOBJECT_TO_MOBJECT_BUFFER) shift_distance = mob.width / 2.0 + buff mob.shift(self.get_direction() * shift_distance) return self def get_text(self, *text, **kwargs): text_mob = Tex(*text) self.put_at_tip(text_mob, **kwargs) return text_mob def get_tex(self, *tex, **kwargs): tex_mob = MathTex(*tex) self.put_at_tip(tex_mob, **kwargs) return tex_mob def get_tip(self): # Returns the position of the seventh point in the path, which is the tip. if config["renderer"] == "opengl": return self.points[34] return self.points[28] # = 7*4
[docs] def get_direction(self): vect = self.get_tip() - self.get_center() return vect / np.linalg.norm(vect)
[docs]class BraceLabel(VMobject, metaclass=ConvertToOpenGL): """Create a brace with a label attached. Parameters ---------- obj The mobject adjacent to which the brace is placed. text The label text. brace_direction The direction of the brace. By default ``DOWN``. label_constructor A class or function used to construct a mobject representing the label. By default :class:`~.MathTex`. font_size The font size of the label, passed to the ``label_constructor``. buff The buffer between the mobject and the brace. brace_config Arguments to be passed to :class:`.Brace`. kwargs Additional arguments to be passed to :class:`~.VMobject`. """ def __init__( self, obj: Mobject, text: str, brace_direction: np.ndarray = DOWN, label_constructor: type = MathTex, font_size: float = DEFAULT_FONT_SIZE, buff: float = 0.2, brace_config: dict | None = None, **kwargs, ): self.label_constructor = label_constructor super().__init__(**kwargs) self.brace_direction = brace_direction if brace_config is None: brace_config = {} self.brace = Brace(obj, brace_direction, buff, **brace_config) if isinstance(text, (tuple, list)): self.label = self.label_constructor(font_size=font_size, *text, **kwargs) else: self.label = self.label_constructor(str(text), font_size=font_size) self.brace.put_at_tip(self.label) self.add(self.brace, self.label) def creation_anim(self, label_anim=FadeIn, brace_anim=GrowFromCenter): return AnimationGroup(brace_anim(self.brace), label_anim(self.label)) def shift_brace(self, obj, **kwargs): if isinstance(obj, list): obj = self.get_group_class()(*obj) self.brace = Brace(obj, self.brace_direction, **kwargs) self.brace.put_at_tip(self.label) return self def change_label(self, *text, **kwargs): self.label = self.label_constructor(*text, **kwargs) self.brace.put_at_tip(self.label) return self def change_brace_label(self, obj, *text, **kwargs): self.shift_brace(obj) self.change_label(*text, **kwargs) return self
[docs]class BraceText(BraceLabel): def __init__(self, obj, text, label_constructor=Tex, **kwargs): super().__init__(obj, text, label_constructor=label_constructor, **kwargs)
[docs]class BraceBetweenPoints(Brace): """Similar to Brace, but instead of taking a mobject it uses 2 points to place the brace. A fitting direction for the brace is computed, but it still can be manually overridden. If the points go from left to right, the brace is drawn from below. Swapping the points places the brace on the opposite side. Parameters ---------- point_1 : The first point. point_2 : The second point. direction : The direction from which the brace faces towards the points. Examples -------- .. manim:: BraceBPExample class BraceBPExample(Scene): def construct(self): p1 = [0,0,0] p2 = [1,2,0] brace = BraceBetweenPoints(p1,p2) self.wait(2) """ def __init__( self, point_1: Sequence[float] | None, point_2: Sequence[float] | None, direction: Sequence[float] | None = ORIGIN, **kwargs, ): if all(direction == ORIGIN): line_vector = np.array(point_2) - np.array(point_1) direction = np.array([line_vector[1], -line_vector[0], 0]) super().__init__(Line(point_1, point_2), direction=direction, **kwargs)
[docs]class ArcBrace(Brace): """Creates a :class:`~Brace` that wraps around an :class:`~.Arc`. The direction parameter allows the brace to be applied from outside or inside the arc. .. warning:: The :class:`ArcBrace` is smaller for arcs with smaller radii. .. note:: The :class:`ArcBrace` is initially a vertical :class:`Brace` defined by the length of the :class:`~.Arc`, but is scaled down to match the start and end angles. An exponential function is then applied after it is shifted based on the radius of the arc. The scaling effect is not applied for arcs with radii smaller than 1 to prevent over-scaling. Parameters ---------- arc The :class:`~.Arc` that wraps around the :class:`Brace` mobject. direction The direction from which the brace faces the arc. ``LEFT`` for inside the arc, and ``RIGHT`` for the outside. Example ------- .. manim:: ArcBraceExample :save_last_frame: :ref_classes: Arc class ArcBraceExample(Scene): def construct(self): arc_1 = Arc(radius=1.5,start_angle=0,angle=2*PI/3).set_color(RED) brace_1 = ArcBrace(arc_1,LEFT) group_1 = VGroup(arc_1,brace_1) arc_2 = Arc(radius=3,start_angle=0,angle=5*PI/6).set_color(YELLOW) brace_2 = ArcBrace(arc_2) group_2 = VGroup(arc_2,brace_2) arc_3 = Arc(radius=0.5,start_angle=-0,angle=PI).set_color(BLUE) brace_3 = ArcBrace(arc_3) group_3 = VGroup(arc_3,brace_3) arc_4 = Arc(radius=0.2,start_angle=0,angle=3*PI/2).set_color(GREEN) brace_4 = ArcBrace(arc_4) group_4 = VGroup(arc_4,brace_4) arc_group = VGroup(group_1, group_2, group_3, group_4).arrange_in_grid(buff=1.5) self.add( """ def __init__( self, arc: Arc | None = None, direction: Sequence[float] = RIGHT, **kwargs, ): if arc is None: arc = Arc(start_angle=-1, angle=2, radius=1) arc_end_angle = arc.start_angle + arc.angle line = Line(UP * arc.start_angle, UP * arc_end_angle) scale_shift = RIGHT * np.log(arc.radius) if arc.radius >= 1: line.scale(arc.radius, about_point=ORIGIN) super().__init__(line, direction=direction, **kwargs) self.scale(1 / (arc.radius), about_point=ORIGIN) else: super().__init__(line, direction=direction, **kwargs) if arc.radius >= 0.3: self.shift(scale_shift) else: self.shift(RIGHT * np.log(0.3)) self.apply_complex_function(np.exp) self.shift(arc.get_arc_center())