June 1999
Intermediate to advanced
340 pages
10h 10m
English
Content preview from PNG: The Definitive Guide
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Glossary
This section defines some of the technical terms and acronyms used throughout the book. More glossary entries may be found in Section 11 of the PNG Specification, Version 1.1. Terms in italic are defined in this glossary.
alpha channel
A special channel that associates transparency (or opacity) with an image. An image without an alpha channel is considered to be completely opaque; an image with an alpha channel may be opaque in some areas, fully transparent in other areas, and partially transparent in still others. There are two types of alpha, associated and unassociated. Associated (or premultiplied) alpha replaces all of the nonalpha (color or grayscale) information in the image with the values it would have if the image were displayed against a black background; for example, in an RGB image with a premultiplied alpha channel, all RGB values in completely transparent regions are replaced by black pixels. This form can be rendered faster (especially against black backgrounds, where the alpha channel can be completely ignored), but it amounts to a lossy transformation of the image data. Unassociated alpha leaves the nonalpha values untouched; this is the kind supported by PNG.
ANSI
American National Standards Institute, the U.S. standardization body responsible for such standards as the ANSI C programming language.
anti-aliasing
A procedure for reducing the appearance of jaggedness around high-contrast features such as lines or text in a raster image. Anti-aliasing ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.