From time to time I create something useful or learn how to program something. These notes describe my results.

Using PHP Global

The 'global' directive in PHP is unlike that in any other language. When I finally figured it out, I wrote this note.

Changing Photo Metadata

Every photo has meta-data, time stamp, shutter speed, and a lot more, including captions. At one time I wanted to automate adding captions. This note summarizes the results of my research.

Exception Handling in PDFBox

The developers of PDF Box were debating how to handle exceptions. In this note, my bottom line was to suggest reduced reliance on exceptions.

Scaling Pages and Images

For a photo tagging application I wanted to relate a real world map to an on-screen map. This note describes how to convert co-ordinates between the two.

How to start writing a Java program

A working interactiveprogram with notes on how to adapt it to be your own application.

User Interface Tricks

Various tools and techniques for user interface programming. Especially highlighting the use of HTMLEditorKit to create flexible, discursive user interfaces.

Pictools Overview

The physpics website is driven by the Pictools package described here.