Manim

导出视频

在 manim 文件夹下面

1	python -m manim .\mytst.py Position -pl

视频渲染选项

1
2
3

-pm  1280*740 30fps
-pl  854*480 15fps
-p   2560*1440 60fps

如果渲染多个场景，把 p 换成 a

文字和位置

class WriteText(Scene):
    def construct(self):
        text = TextMobject("This is some text")
        # self.play(Write(text)) # 写字动画（从左到右）
        self.play(FadeIn(text), runtime=3) # 淡入效果, 持续3秒
        self.wait(1) # 等待 1 秒（从上一个效果开始计时）
        self.remove(text) # 文本立即消失
        self.wait(1)

class Position(Scene):
    def construct(self):
        object = Dot()   # 点 
        ReferenceText = TextMobject("text")  
        self.add(object, ReferenceText) 

        object.to_edge(UP) # 到上面的边
        self.wait()
        object.to_corner(UL, buff=1.50) # 到左上的边 buff 是与边界的间距
        self.wait()
        object.move_to(UP*2 + RIGHT) # 后面是一个移动向量
        self.wait()
        
       
        vector = np.array([-3, -2, 0])
        object.move_to(ReferenceText.get_center() + 5*RIGHT) # 把点放到text的右边5格
        self.wait()
        object.next_to(ReferenceText, RIGHT, buff=5) # 和上一行一样
        self.wait()
        object.shift(RIGHT) # 向右移动一个
     
        self.wait()

变换

class Transform1(Scene):
    def construct(self):
        texto1 = TextMobject("First text")
        texto2 = TextMobject("Second text")
        self.play(Write(texto1)) 
        self.wait()
        self.play(Transform(texto1, texto2))   # 把一个变成另一个
        self.wait()

所有改变都是改变第一个 texto1 = texto2 相当于赋值语句，也可以 ReplacementTransform 把当前物体变成后面一个

公式变换的例子

class TransformFormula(Scene):
    def construct(self):
        formula = TexMobject(
            "\\frac{d}{dx}",
            "(",
            "u",
            "+",
            "v",
            ")",
            "=",
            "\\frac{d}{dx}",
            "u",
            "+",
            "\\frac{d}{dx}",
            "v"
        )
        formula.scale(2)
        self.play(Write(formula[0:7]))
        self.wait()
        self.play(
            ReplacementTransform(formula[2].copy(), formula[8]),
            ReplacementTransform(formula[4].copy(), formula[11]),
            ReplacementTransform(formula[3].copy(), formula[9])
        )
        self.wait()
        self.play(
            ReplacementTransform(formula[0].copy(), formula[7]),
            ReplacementTransform(formula[0].copy(), formula[10])
        )
        self.wait()

把变换存在数组里

class TransformFormula(Scene):
    def construct(self):
        formula = TexMobject(
            "\\frac{d}{dx}",
            "(",
            "u",
            "+",
            "v",
            ")",
            "=",
            "\\frac{d}{dx}",
            "u",
            "+",
            "\\frac{d}{dx}",
            "v"
        )
        formula.scale(2)
        self.play(Write(formula[0:7]))
        self.wait()
        changes = [
            # step 1
            [(2,4,3),
            # | | |
             (8,11,9)],
            # step 2
            [(0,0),
            # | |
             (7,10)]
        ]
        for pre_ind, post_ind in changes:
            self.play(
                *[
                    ReplacementTransform(formula[i].copy(), formula[j])
                    for i,j in zip(pre_ind, post_ind)
                ]
            )
        self.wait()