Two common techniques used in computer graphics are clipping and masking. Both techniques hide an area of a graphic element. Clipping defines an area of a graphic element that will be visible. Everything outside this region will not be visible, it will be "clipped".
Masking is a similar technique that hides an area of a graphic element, but whereas clipping makes a sharp boarder between the visible and clipped areas, masking makes a blurry boundary between the visible and masked areas. A mask defines an area where each pixel of the mask has a degree transparency and opaqueness letting some of the graphic element show through.
In the example shown above, the points of a polygon that forms a star are defined as the clipPath and the id of the clipPath is used with the clip-path attribute in the leaves image tag.
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