animated_size_and_fade library Null safety

Classes

AnimatedSizeAndFade
The AnimatedSizeAndFade widget does a fade and size transition between a "new" widget and an "old" widget/ previously set as a child. The "old" and the "new" children must have the same width, but can have different heights, and you don't need to know their sizes in advance. You can also define a duration and curve for both the fade and the size, separately. [...]