opacity of Vector() and DashedVMobject(Vector) (Manim 0.17.3)

[uwezi]

Description of bug / unexpected behavior

The set stroke opacity and fill opacity is not obeyed for arrow heads - especially not when used within a DashedVMobject

Expected behavior

The opacity of the fill of the arrowhead is kept at 1.0 and not affected by setting the opacity value.

How to reproduce the issue

Code for reproducing the problem

class arrowTransp(Scene):
    def construct(self):
        arr1 = Arrow(ORIGIN,[2,2,0], color=GREEN).shift(2*LEFT+UP)
        arr2 = arr1.copy().shift(DOWN).set_fill(opacity=0.4).set_stroke(opacity=0.4)
        arr3 = VGroup(DashedVMobject(arr2.copy().shift(DOWN))).set_fill(opacity=0.4, family=True).set_stroke(opacity=0.4, family=True)
        self.add(arr1,arr2,arr3)
        arr4 = Arrow(ORIGIN,[2,2,0], color=RED, tip_shape=StealthTip).shift(RIGHT+UP)
        arr5 = arr4.copy().shift(DOWN).set_fill(opacity=0.4).set_stroke(opacity=0.4)
        arr6 = VGroup(DashedVMobject(arr5.copy().shift(DOWN))).set_fill(opacity=0.4, family=True).set_stroke(opacity=0.4, family=True)
        self.add(arr4,arr5,arr6)  

Additional media files

Images/GIFs

System specifications

System Details

- ManimCE 0.17.3 - OS: Windows 10 64 bit - Python version: 3.9.8

[uwezi]

Ok I discovered the cause of the main problem: for every piece of the dashed line also a copy of the arrow head is added to the dashed VMobject:

class arrowTransp(Scene):
    def construct(self):
        arr1 = Arrow(ORIGIN,[2,2,0], color=GREEN).shift(2*LEFT+UP)
        arr2 = arr1.copy().shift(DOWN).set_fill(opacity=0.4).set_stroke(opacity=0.4)
        arr3 = DashedVMobject(arr2.copy().shift(DOWN)).set_fill(opacity=0.4, family=True).set_stroke(opacity=0.4, family=True)
        self.add(arr1,arr2,arr3)
        arr3a = arr3.copy().shift(2*LEFT) 
        for i in range(len(arr3a)):
            arr3a[i].shift(0.3*i*DOWN)
        self.add(arr3a,index_labels(arr3a)) 
        arr4 = Arrow(ORIGIN,[2,2,0], color=RED, tip_shape=StealthTip).shift(RIGHT+UP)
        arr5 = arr4.copy().shift(DOWN).set_fill(opacity=0.4).set_stroke(opacity=0.4)
        arr6 = DashedVMobject(arr5.copy().shift(DOWN)).set_fill(opacity=0.4, family=True).set_stroke(opacity=0.4, family=True)
        self.add(arr4,arr5,arr6)
        arr6a = arr6.copy().shift(2*RIGHT) 
        for i in range(len(arr6a)):
            arr6a[i].shift(0.3*i*DOWN)
        self.add(arr6a,index_labels(arr6a)) 

[MrDiver]

That seems like a big problem!

[EngRia]

I am taking a shot at this