SliverOpacity class

A sliver widget that makes its sliver child partially transparent.

This class paints its sliver child into an intermediate buffer and then blends the sliver back into the scene partially transparent.

For values of opacity other than 0.0 and 1.0, this class is relatively expensive because it requires painting the sliver child into an intermediate buffer. For the value 0.0, the sliver child is not painted at all. For the value 1.0, the sliver child is painted immediately without an intermediate buffer.

See also:

• Opacity, which can apply a uniform alpha effect to its child using the RenderBox layout protocol.
• AnimatedOpacity, which uses an animation internally to efficiently animate Opacity.
• SliverVisibility, which can hide a child more efficiently (albeit less subtly, because it is either visible or hidden, rather than allowing fractional opacity values). Specifically, the SliverVisibility.maintain constructor is equivalent to using a sliver opacity widget with values of 0.0 or 1.0.