Merge pull request #220 from 3b1b/eola2

Eola2

mobject/matrix.py

@@ -2,8 +2,10 @@ from __future__ import absolute_import
 
 import numpy as np
 
-from mobject.mobject import Mobject
+from mobject.numbers import DecimalNumber
+from mobject.numbers import Integer
 from mobject.svg.tex_mobject import TexMobject
+from mobject.svg.tex_mobject import TextMobject
 from mobject.types.vectorized_mobject import VGroup
 from mobject.types.vectorized_mobject import VMobject
 from mobject.shape_matchers import BackgroundRectangle
@@ -38,7 +40,7 @@ def vector_coordinate_label(vector_mob, integer_labels=True,
         vect = np.round(vect).astype(int)
     vect = vect[:n_dim]
     vect = vect.reshape((n_dim, 1))
-    label = Matrix(vect, add_background_rectangles=True)
+    label = Matrix(vect, add_background_rectangles_to_entries=True)
     label.scale(VECTOR_LABEL_SCALE_FACTOR)
 
     shift_dir = np.array(vector_mob.get_end())
@@ -55,9 +57,13 @@ def vector_coordinate_label(vector_mob, integer_labels=True,
 
 class Matrix(VMobject):
     CONFIG = {
-        "v_buff": 0.5,
-        "h_buff": 1,
-        "add_background_rectangles": False
+        "v_buff": 0.8,
+        "h_buff": 1.3,
+        "add_background_rectangles_to_entries": False,
+        "include_background_rectangle": False,
+        "element_to_mobject": TexMobject,
+        "element_to_mobject_config": {},
+        "element_alignment_corner": DR,
     }
 
     def __init__(self, matrix, **kwargs):
@@ -69,34 +75,34 @@ class Matrix(VMobject):
         matrix = np.array(matrix)
         if matrix.ndim == 1:
             matrix = matrix.reshape((matrix.size, 1))
-        if not isinstance(matrix[0][0], Mobject):
-            matrix = matrix.astype("string")
-            matrix = self.string_matrix_to_mob_matrix(matrix)
-        self.organize_mob_matrix(matrix)
-        self.add(*matrix.flatten())
+        mob_matrix = self.matrix_to_mob_matrix(matrix)
+        self.organize_mob_matrix(mob_matrix)
+        self.elements = VGroup(*mob_matrix.flatten())
+        self.add(self.elements)
         self.add_brackets()
         self.center()
-        self.mob_matrix = matrix
-        if self.add_background_rectangles:
-            for mob in matrix.flatten():
+        self.mob_matrix = mob_matrix
+        if self.add_background_rectangles_to_entries:
+            for mob in self.elements:
                 mob.add_background_rectangle()
+        if self.include_background_rectangle:
+            self.add_background_rectangle()
 
-    def string_matrix_to_mob_matrix(self, matrix):
-        return np.array([
-            map(TexMobject, row)
-            for row in matrix
-        ]).reshape(matrix.shape)
+    def matrix_to_mob_matrix(self, matrix):
+        return np.vectorize(
+            lambda e: self.element_to_mobject(
+                e, **self.element_to_mobject_config
+            )
+        )(matrix)
 
     def organize_mob_matrix(self, matrix):
         for i, row in enumerate(matrix):
             for j, elem in enumerate(row):
                 mob = matrix[i][j]
-                if i == 0 and j == 0:
-                    continue
-                elif i == 0:
-                    mob.next_to(matrix[i][j - 1], RIGHT, self.h_buff)
-                else:
-                    mob.next_to(matrix[i - 1][j], DOWN, self.v_buff)
+                mob.move_to(
+                    i * self.v_buff * DOWN + j * self.h_buff * RIGHT,
+                    self.element_alignment_corner
+                )
         return self
 
     def add_brackets(self):
@@ -110,6 +116,10 @@ class Matrix(VMobject):
         self.brackets = VGroup(l_bracket, r_bracket)
         return self
 
+    def add_background_rectangle(self):
+        self.background_rectangle = BackgroundRectangle(self)
+        self.add_to_back(self.background_rectangle)
+
     def set_color_columns(self, *colors):
         for i, color in enumerate(colors):
             VGroup(*self.mob_matrix[:, i]).set_color(color)
@@ -128,3 +138,42 @@ class Matrix(VMobject):
 
     def get_brackets(self):
         return self.brackets
+
+
+class DecimalMatrix(Matrix):
+    CONFIG = {
+        "element_to_mobject": DecimalNumber,
+        "element_to_mobject_config": {"num_decimal_points": 1}
+    }
+
+
+class IntegerMatrix(Matrix):
+    CONFIG = {
+        "element_to_mobject": Integer,
+    }
+
+
+class MobjectMatrix(Matrix):
+    CONFIG = {
+        "element_to_mobject": lambda m: m,
+    }
+
+
+def get_det_text(matrix, determinant=None, background_rect=True, initial_scale_factor=2):
+    parens = TexMobject(["(", ")"])
+    parens.scale(initial_scale_factor)
+    parens.stretch_to_fit_height(matrix.get_height())
+    l_paren, r_paren = parens.split()
+    l_paren.next_to(matrix, LEFT, buff=0.1)
+    r_paren.next_to(matrix, RIGHT, buff=0.1)
+    det = TextMobject("det").next_to(l_paren, LEFT, buff=0.1)
+    if background_rect:
+        det.add_background_rectangle()
+    det_text = VMobject(det, l_paren, r_paren)
+    if determinant is not None:
+        eq = TexMobject("=")
+        eq.next_to(r_paren, RIGHT, buff=0.1)
+        result = TexMobject(str(determinant))
+        result.next_to(eq, RIGHT, buff=0.2)
+        det_text.add(eq, result)
+    return det_text

old_projects/eola/chapter3.py

@@ -887,7 +887,7 @@ class MatrixVectorMultiplication(LinearTransformationScene):
         )
         concrete_matrix = Matrix(
             copy.deepcopy(abstract_matrix),
-            add_background_rectangles = True
+            add_background_rectangles_to_entries = True
         )
         concrete_matrix.to_edge(UP)
         if self.abstract:

old_projects/eola/chapter4.py

@@ -106,7 +106,7 @@ class FollowLinearCombination(LinearTransformationScene):
             direction = "right", color = Y_COLOR
         )
         vect = self.add_vector(vect_coords)
-        vect_array = Matrix(["x", "y"], add_background_rectangles = True)
+        vect_array = Matrix(["x", "y"], add_background_rectangles_to_entries = True)
         v_equals = TexMobject(["\\vec{\\textbf{v}}", "="])
         v_equals.split()[0].set_color(YELLOW)
         v_equals.next_to(vect_array, LEFT)

old_projects/eola/chapter5.py

@@ -1,24 +1,6 @@
 from big_ol_pile_of_manim_imports import *
 from eola.chapter3 import MatrixVectorMultiplicationAbstract
 
-def get_det_text(matrix, determinant = None, background_rect = True):
-    parens = TexMobject(["(", ")"])
-    parens.scale(2)
-    parens.stretch_to_fit_height(matrix.get_height())
-    l_paren, r_paren = parens.split()
-    l_paren.next_to(matrix, LEFT, buff = 0.1)
-    r_paren.next_to(matrix, RIGHT, buff = 0.1)
-    det = TextMobject("det").next_to(l_paren, LEFT, buff = 0.1)
-    if background_rect:
-        det.add_background_rectangle()
-    det_text = VMobject(det, l_paren, r_paren)
-    if determinant is not None:
-        eq = TexMobject("=")
-        eq.next_to(r_paren, RIGHT, buff = 0.1)
-        result = TexMobject(str(determinant))
-        result.next_to(eq, RIGHT, buff = 0.2)
-        det_text.add(eq, result)
-    return det_text
 
 class Blob(Circle):
     CONFIG = {

scene/vector_space_scene.py

@@ -10,6 +10,7 @@ from animation.creation import Write
 from animation.transform import ApplyFunction
 from animation.transform import ApplyPointwiseFunction
 from animation.creation import FadeOut
+from animation.creation import GrowArrow
 from animation.transform import Transform
 from mobject.mobject import Mobject
 from mobject.svg.tex_mobject import TexMobject
@@ -20,7 +21,7 @@ from scene.scene import Scene
 from mobject.geometry import Arrow
 from mobject.geometry import Dot
 from mobject.geometry import Line
-from mobject.geometry import Square
+from mobject.geometry import Rectangle
 from mobject.geometry import Vector
 from mobject.coordinate_systems import Axes
 from mobject.coordinate_systems import NumberPlane
@@ -37,6 +38,12 @@ Y_COLOR = RED_C
 Z_COLOR = BLUE_D
 
 
+# TODO: Much of this scene type seems dependent on the coordinate system chosen.
+# That is, being centered at the origin with grid units corresponding to the
+# arbitrary space units.  Change it!
+#
+# Also, methods I would have thought of as getters, like coords_to_vector, are
+# actually doing a lot of animating.
 class VectorScene(Scene):
     CONFIG = {
         "basis_vector_stroke_width": 6
@@ -65,11 +72,19 @@ class VectorScene(Scene):
         self.add(axes)
         self.freeze_background()
 
+    def get_vector(self, numerical_vector, **kwargs):
+        return Arrow(
+            self.plane.coords_to_point(0, 0),
+            self.plane.coords_to_point(*numerical_vector[:2]),
+            buff=0,
+            **kwargs
+        )
+
     def add_vector(self, vector, color=YELLOW, animate=True, **kwargs):
         if not isinstance(vector, Arrow):
             vector = Vector(vector, color=color, **kwargs)
         if animate:
-            self.play(ShowCreation(vector))
+            self.play(GrowArrow(vector))
         self.add(vector)
         return vector
 
@@ -106,6 +121,7 @@ class VectorScene(Scene):
         ])
 
     def get_vector_label(self, vector, label,
+                         at_tip=False,
                          direction="left",
                          rotate=False,
                          color=None,
@@ -120,6 +136,11 @@ class VectorScene(Scene):
         label.scale(label_scale_factor)
         label.add_background_rectangle()
 
+        if at_tip:
+            vect = vector.get_vector()
+            vect /= np.linalg.norm(vect)
+            label.next_to(vector.get_end(), vect, buff=SMALL_BUFF)
+        else:
             angle = vector.get_angle()
             if not rotate:
                 label.rotate(-angle, about_point=ORIGIN)
@@ -281,10 +302,10 @@ class LinearTransformationScene(VectorScene):
     }
 
     def setup(self):
+        # The has_already_setup attr is to not break all the old Scenes
         if hasattr(self, "has_already_setup"):
             return
         self.has_already_setup = True
-        # ^This is to not break all the old Scenes
         self.background_mobjects = []
         self.foreground_mobjects = []
         self.transformable_mobjects = []
@@ -311,6 +332,7 @@ class LinearTransformationScene(VectorScene):
             )
             self.moving_vectors += list(self.basis_vectors)
             self.i_hat, self.j_hat = self.basis_vectors
+            self.add(self.basis_vectors)
 
     def add_special_mobjects(self, mob_list, *mobs_to_add):
         for mobject in mobs_to_add:
@@ -321,6 +343,7 @@ class LinearTransformationScene(VectorScene):
     def add_background_mobject(self, *mobjects):
         self.add_special_mobjects(self.background_mobjects, *mobjects)
 
+    # TODO, this conflicts with Scene.add_fore
     def add_foreground_mobject(self, *mobjects):
         self.add_special_mobjects(self.foreground_mobjects, *mobjects)
 
@@ -331,15 +354,26 @@ class LinearTransformationScene(VectorScene):
         mobject.target = target_mobject
         self.add_special_mobjects(self.moving_mobjects, mobject)
 
-    def add_unit_square(self, color=YELLOW, opacity=0.3, animate=False):
-        square = Square(color=color, side_length=1)
-        square.shift(-square.get_corner(DOWN + LEFT))
+    def get_unit_square(self, color=YELLOW, opacity=0.3, stroke_width=3):
+        square = Rectangle(
+            color=color,
+            width=self.plane.get_x_unit_size(),
+            height=self.plane.get_y_unit_size(),
+            stroke_color=color,
+            stroke_width=stroke_width,
+            fill_color=color,
+            fill_opacity=opacity
+        )
+        square.move_to(self.plane.coords_to_point(0, 0), DL)
+        return square
+
+    def add_unit_square(self, animate=False, **kwargs):
+        square = self.get_unit_square(**kwargs)
         if animate:
-            added_anims = map(Animation, self.moving_vectors)
-            self.play(ShowCreation(square), *added_anims)
-            self.play(square.set_fill, color, opacity, *added_anims)
-        else:
-            square.set_fill(color, opacity)
+            self.play(
+                DrawBorderThenFill(square),
+                Animation(Group(*self.moving_vectors))
+            )
         self.add_transformable_mobject(square)
         self.bring_to_front(*self.moving_vectors)
         self.square = square
@@ -357,12 +391,19 @@ class LinearTransformationScene(VectorScene):
         self.add_foreground_mobject(coords)
         return coords
 
-    def add_transformable_label(self, vector, label, new_label=None, **kwargs):
+    def add_transformable_label(
+            self, vector, label,
+            transformation_name="L",
+            new_label=None,
+            **kwargs):
         label_mob = self.label_vector(vector, label, **kwargs)
         if new_label:
             label_mob.target_text = new_label
         else:
-            label_mob.target_text = "L(%s)" % label_mob.get_tex_string()
+            label_mob.target_text = "%s(%s)" % (
+                transformation_name,
+                label_mob.get_tex_string()
+            )
         label_mob.vector = vector
         label_mob.kwargs = kwargs
         if "animate" in label_mob.kwargs:
@@ -427,6 +468,9 @@ class LinearTransformationScene(VectorScene):
     def apply_matrix(self, matrix, **kwargs):
         self.apply_transposed_matrix(np.array(matrix).T, **kwargs)
 
+    def apply_inverse(self, matrix, **kwargs):
+        self.apply_matrix(np.linalg.inv(matrix), **kwargs)
+
     def apply_transposed_matrix(self, transposed_matrix, **kwargs):
         func = self.get_transposed_matrix_transformation(transposed_matrix)
         if "path_arc" not in kwargs: