Figma mask (not frame)
While frame has a built-in clip content property, figma also has a traditional graphics tool masking layer just like in photoshop.
A slightly bizarre structure
While frame and other code implementation (css container or flutter clip) has a straight forward hierarchical structure, masking in design tool does not have a hierarchical structure.
Here is a example of how making works
| (mask) | a | b | d | e | f | g -- none will be masked
| a | b | (mask) | d | e | f | g -- a, b will be masked
| a | b | d | e | f | g | (mask) -- all will be masked
A target masking layer will have property
isMask set to true.
Web - css
With Positioning + overflow hidden
/* wip */