June 1999
Intermediate to advanced
340 pages
10h 10m
English
Content preview from PNG: The Definitive GuideBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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.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.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.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.
Chapter 13. Reading PNG Images
As with almost any kind of programming project, there are numerous alternatives one can take when writing a PNG-supporting program. Complete or partial code for reading and/or writing PNGs is available for the C, C++, Java, Pascal, tcl/tk, Python, and Visual Basic languages, at a minimum; some of it is in the form of commercial libraries, some as free source code, and some as a combination of both. Many of these in alternatives are listed in Chapter 16, “Other Libraries and Concluding Remarks”. One can even read and write PNG images directly, in effect implementing one's own PNG library, but this is a rather large undertaking and is generally not recommended except under special circumstances.
The granddaddy of all PNG libraries is libpng, the free reference library available as Standard (ANSI) C source code and used by many, if not most, PNG-supporting applications. It uses the similarly free zlib library (portable C source code) for compression and decompression, and in these next few chapters I'll provide detailed demonstrations of how to write programs with both.
13.1. A libpng-Based, PNG-Reading Demo Program
In order to provide a concrete demonstration of how to use libpng to read PNG images, I have written a complete (albeit basic) PNG viewer in Standard C. It consists of two main source files: a platform-independent one that includes all of the PNG- and libpng-specific code (readpng.c), and a platform-dependent file that contains all of the ...
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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.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
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.