This page lists various projects I have worked on in my spare time:
Suggestions, bug reports, by email to johns *a*t* chiark.greenend.org.uk.
This is a reusable library which will allow Windows applications to provide end-users with powerful built-in scripting capabilities. It consists of a simple external API to allow flexible and minimum-impact integration with the host code. Internally it contains a document/project manager to maintain correspondance between host application projects and their associated scripts, an interface to an Active Scripting Engine to execute the scripts and an IDE including an integrated code editor to allow writing, running and debugging the scripts.
The Active Scripting interfaces are used to provide access to arbitrary execution engines. This simplifies the code by not having to implement a language engine, and insulating it from the details of any specific language, whilst allowing the end-user to choose the language they are most comfortable scripting in, making the system more accessible. JavaScript and VBScript are provided with Windows, and Active Scripting Engines for many other languages are widely available.
This project seeks to document all the recorded DJ setlists for a local nightclub, to provide additional statistics based on the tracks played, additional information on each band or track played, and the DJs who played them.
Written as a helper application for the music database, this tool allows for efficient entry of audio CD track timings taken from the CD Table Of Contents (TOC). The source demonstrates the following methods:
A simple oscilloscope and spectrum analyzer applet for Windows. Takes input from the default DirectSound capture device.
Flame was always my favourite screensaver under X Windows. This is a port to Microsoft Windows which sports a simple settings dialog (original was controlled by command-line arguments, by editing Xresources directly or using a standalone config panel), control-panel preview and demo modes and multiple monitor support.
The screensaver shell is new, but the original screen hack code was lifted from Jamie Zawinski's xscreensaver package, with minor modifications to parameterise it for multi-monitor displays under Win32. The original code contained this copyright/license notice.
This layout allows easy and mnemonic access to many accented and special characters using a standard UK QWERTY keyboard.
The version for NT OSs was constructed using Microsoft's free Keyboard Layout Creator tool, the version for 9x OSs was built by hand with very little useful documentation on the file format used.
In 2002 satellite imagery from Terra MODIS was made publicly available under GPL (full data credits within MapShow2.zip). The full data sets including 24-bit photographic, topographic, bathymetric, land-use classification, water cover and cloud cover maps of the entire planet at 30 arcsecond (1km at the equator) resolution. This cut down viewer uses a prescaled version of the photographic (original filesize was 2.6Gb!) and landcover classification data and remaps the cylindrical projection to display a spinning (but mouse draggable) globe. Requires a 24/32-bit display mode and a fairly fast machine!
The motivation behind this project was to see how hard it would be to visualise large (multi-Gigabyte) datasets in real time. The answer is that on today's commodity PC hardware it is very hard indeed. The display functions tolerably well on the scaled-down dataset included here, but the sheer size of the data makes loading it all into memory unworkable and extracting an arbitrary subset of the data directly from the original file is killed by the number of head seeks. Extracting a 1000x1000 pixel subset out of the original 43200x21600 data requires 1000 seeks, which can easily take several seconds even if the total amount of data could be transferred in milliseconds if it were contiguous. It may be possible to drastically reduce the number of seeks using approaches such as precomputing scaled down copies of the data (divided by 2, 4, 8 etc.) and reordering the data into tiled sections (such that loading, say, 10 scanlines at a time requires a single head seek) or along a Hilbert or other space-filling curve. The tradeoff here is that the fewer head seeks, the more unwanted data has to be loaded alongside the wanted subsection, and this may still not reach the original goal of allowing pan and zoom over the whole dataset at full framerate. (Assuming full framerate is 25 fps, this gives 40ms to load and process all required data. Even with optimistic pre-loading this is a difficult limit.)
CopyPath provides "Copy Path to Clipboard" context menus within Explorer. To install place the executable somewhere in the PATH (for example, in the Windows System/System32 directory) and run the associated .reg file.
GotoClip allows you to launch a given application with the current clipboard
contents on the command-line, for example for launching a web-browser to view a
copied URL. To use, create a shortcut on the Desktop, Start Menu or Quick Launch
Bar, and edit the shortcut path to include the program you want to launch. For
example, to launch Internet Explorer on a URL copied to the clipboard, change
the shortcut path from "...\GotoClip.exe" to
"...\GotoClip.exe" iexplore.exe. (Tip: You can also launch URLs by
pasting them directly into the Start->Run dialog, which can also be quickly
accessed by hitting Windows-R. But this will probably replace an existing
browser window with the target at random unless you hack the registry to disable
DDE for (at least) the shell http open verb.)
UNCResolve converts Windows paths into either UNC format or file: URLs, useful for emailing file links around an intranet when not everyone may have the same drive mappings configured. (Paths using a drive letter may not be portable between different users. Paths using UNC \\SERVER\SHARE format or URL file://SERVER/share format are portable. UNC format will be directly clickable within some mailers or can be pasted into Windows Explorer's location bar. URLs are more widely supported within email clients or can be pasted into your web browser's location bar. To use, run and use the System Tray icon to convert paths as required.
SMteePD acts as a proxy for outgoing network connections as an aid to protocol debugging. By setting it up to listen on local port 25, or 80 for HTTP, and reconfiguring the local client to connect to it rather than the remote server, a complete dump of the two-way conversation between the two can be produced. Also demonstrates correct use of WSAEventSelect without stalling or data-loss.
A friend complained that their favourite key bindings for game playing were close enough to Alt-Tab that they were repeatedly accidentally dropping out of the game. This very simple applet prevents this by temporarily overriding the Alt-Tab sequence to prevent it from switching tasks.
The screen hack code comes from the xscreensaver package by Jamie Zawinski. The code used (in file ./hacks/flame.c within the xscreensaver source tree, and ./hack.cpp within the Win32 Flame source tree) bears the following notice: