Lately I have seen zip, rar, and 7-zip compression related topics being searched for on this site. Since those searches are coming up empty thought it would be a good idea to post about some of the available libraries, and examples related to these common desktop compression methods.
Here are some open source alternatives for handling these common compression types:
ZipKit – This is an Objective-C .zip compression library from Karl Moskowski that can handle the standard PKZip format. You can perform all the expected zip functions, and interrupt the compression cleanly so you can run your unzipping in a separate thread, and cancel if neccessary without any issues. An example project is included – be sure to check the documentation wiki forexamples on how to include this library within your apps.
Unrar4iOS – From Rog?rio Ara?jo this is an example that includes the C++ Portable Unrar project and provides a working demonstration showing how view the contents of a rar file, and extract files using Objective-C.
7-Zip Lzma SDK - This is a multi-language SDK for handling 7-zip files. Mo Dejong has created an example demonstrating how to use the LZMA SDK to decompress 7-zip libraries on iOS devices. You can find the example on his website here.
I have received inquiries quit a few times from visiting developers asking about available open source libraries for creating charts on iOS devices. It is definitely understandable as many of the commercial charting libraries come with a very hefty up front cost.
While there are quite a few open source libraries that have charting and plotting features that run on iOS here are a few that are designed specifically for this purpose allowing you to draw many different kinds of graphs.
Core-Plot – This is definitely the top recommendation for open source charting libraries on iOS. You can create many different kinds of charts – line charts, pie charts, bar graphs and even for stock charts like candlestick charts, and bar charts using the built in chart types.
Here’s a screenshot showing an example of a couple of the built in chart types:
You can see examples of some of the chart types supported here.
iOS Plot - While there probably are too many situations where Core Plot won’t meet your needs – if you want something different, but want to stick with an Objective-C library this much smaller project from Hon Cheng provides support for line charts, and some very slick looking pie graphs like the one in this screenshot:
You will be able to create nearly any chart using the libraries mentioned above, but if not you might want to mention your chart ideas in the Core Plot discussion group. The core plot community has done a great job of providing updates.