<svg width="355" height="310" version="1.1" xmlns="http://www.w3.org/2000/svg" style="border-style:none;">
<clipPath id="star_mask">
<polygon points="2 112 135 112 174 2 209 112 340 112 230 182 274 300 170 222 65 300 114 182" />
</clipPath>
<image xlink:href="leaves.jpg" x="0" y="0" width="480" height="353" clip-path="url(#star_clip)" />
</svg>
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.
More Graphics Design Tips:
• SVG Matrix Transform Example Code
• Beginning GIMP: From Novice to Professional
• Five Surprising Reasons I Use Krita for Photo Editing
• Inkscape Layers and Z-Order
• Inkscape - How to Join Two Segments at Endnodes
• Free Animated GIF Maker
• Inkscape - How to Delete a Node
• Inscape Text in a Shape
• SVG Basic Shapes Tutorials
• HTML5 Canvas