As the sun sinks over the horizon, animateColor is used to change the sky's color, and the moon and the stars fade in by animating their opacity.

随着太阳落下地平线，使用 animateColor 来改变天空的颜色，通过变化月亮和星星的不透明性使它们渐渐显现出来。

youdao

The KenBurnsFader class handles the fade-in and fade-out of the image using opacity.

kenburnsfader类使用不透明度处理图像的淡入淡出。

youdao

Select Soft Brush tool, set its opacity 20% and size to 30px. Paint a fade dot in the center of the cross.

选择柔角笔刷工具，不透明度为20%，大小30像素，在十字中部画一个虚幻的园点。

youdao