Webopedia on Google+Webopedia on TwitterWebopedia on FacebookTech Bytes Blog
Main » TERM » A »

alpha channel

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.







TECH RESOURCES FROM OUR PARTNERS
LATEST ARTICLES
Slideshow: 5 Hot Holiday Gifts for Tech Enthusiasts

From cute electronic toys to VR gaming, here are 5 hot gifts to give to your special tech enthusiast this holiday season. Read More »

What's Hot in Tech: AI Tops the List

Like everything in technology, AI touches on so many other trends, like self-driving cars and automation, and Big Data and the Internet of Things... Read More »

DevOp's Role in Application Security

As organizations rush to release new applications, security appears to be getting short shrift. DevSecOps is a new approach that holds promise. Read More »

STUDY GUIDES
Java Basics, Part 1

Java is a high-level programming language. This guide describes the basics of Java, providing an overview of syntax, variables, data types and... Read More »

Java Basics, Part 2

This second Study Guide describes the basics of Java, providing an overview of operators, modifiers and control Structures. Read More »

The 7 Layers of the OSI Model

The Open System Interconnection (OSI) model defines a networking framework to implement protocols in seven layers. Use this handy guide to compare... Read More »