When using rsync you may encounter the problem that it sometimes stops in the middle of a transfer with no visible reason. If you ask Google you will find out that also others have this problem occasionally. Unfortunately, the reason and the solution is hidden and hard to find within these articles. I neither could …
Category: Making
Dec 16
Companies Deliver Crappy Software
Pieter Heerema is a skilled sailor currently taking part in the Vendee Globe, the world’s hardest race around the globe. It is a single-handed non-stop sailing race which lasts about 10 to 12 weeks. Pieter had an unexpected severe problem with his auto pilot in the middle of the southern Indian ocean, 4500 kilometers away …
Dec 28
JPEG Support For Libcairo
Libcairo supports several output file formats (PNG, PDF, SVG) and PNG as input format. But often it is necessary to read and write JPG files as well. Libjpeg-turbo does all the JPEG stuff. All you have to do is to combine this with the Cairographics library. I implemented two functions in this small C source …
Dec 16
Cypherpunk.at On Hidden Service
Cypherpunk.at is now available on a Tor hidden service at http://7pd3i34noxnxolha.onion/. Please be aware that this is experimental because it requires a lot of URL rewriting which is done by Apache’s mod_proxy, mod_proxy_http, and mod_proxy_html. I debugged it with Firebug and tried to fix all internal links. Please note that external links to other pages …
Dec 11
Calculating Control Points For Bsplines
This article explains how to calculate the control points for B-Splines. The basic idea is that we want to interpolate a smooth curve into a set of points. B-Splines are a sequence of Bezier curves which solve that problem. But each Bezier curve is defined by four points: the start and end point and two …
Nov 23
HOWTO Render Charts With Smrender
This article is a step-by-step guide to render your own sea charts. I assume that you have already installed it to your system. If not, download the latest version and run ./configure and make and make install as usual. Make sure that you have installed the packages libcairo2-dev, librsvg2-dev, and libfontconfig-dev. You also may have …
Nov 20
Combining ownCloud and syncthing
OwnCloud is a nice cloud solution which is based on free software. It allows companies and users to run their own cloud services thereby not loosing the control on their data. Every day this gets more and more important and you loose control if you use commercial cloud services such as Google, Microsoft, or Amazon. …
Oct 11
Calculating Fractals With Integer Operations
It was in the late ’80s when I started to become interested in fractals. At the time then computers very unbelievable slow compared to what we have today thus I tried to speed up the algorithms in several ways. This article is about using integer operations to calculate fractal images, more specifically I’ll explain how …
Sep 05