In graphics, a portion of each pixel's data that is reserved for transparency information. 32-bit graphics systems contain four channels -- three 8-bit channels for red, green, and blue (RGB) and one 8-bit alpha channel. The alpha channel is really a mask -- it specifies how the pixel's colors should be merged with another pixel when the two are overlaid, one on top of the other.
Typically, you wouldn't define the alpha channel on a pixel-by-pixel basis, but rather per object. Different parts of the object would have different levels of transparency depending on how much you wanted the background to show through. This allows you to create rectangular objects that appear as if they are irregular in shape -- you define the rectangular edges as transparent so that the background shows through. This is especially important for animation, where the background changes from one frame to the next.
Rendering overlapping objects that include an alpha value is called alpha blending.
Featured Partners Sponsored
- Increase worker productivity, enhance data security, and enjoy greater energy savings. Find out how. Download the “Ultimate Desktop Simplicity Kit” now.»
- Find out which 10 hardware additions will help you maintain excellent service and outstanding security for you and your customers. »
- Server virtualization is growing in popularity, but the technology for securing it lags. To protect your virtual network.»
- Before you implement a private cloud, find out what you need to know about automated delivery, virtual sprawl, and more. »