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Electric Magic implemented the Mac-specific portions of the Zorap web plugin, supporting Safari, Firefox and other modern web browsers.

SiteGrinder’s UI is beautifully implemented in Flash, and Electric Magic helped MediaLab get that UI working in older and newer versions of PhotoShop.

Our client’s application is a scriptable form-filling engine, used by their customers to automate computer-based form submission. Their engine is written in Java, and uses the Abbot GUI testing framework to drive third-party UIs. For Mac OS X support we implemented a JNI shim that made the AX API usable from Java.

ZBlackBerry is a suite of code that implements the BlackBerry USB communications protocol in a generic fashion. A few hundred lines of code let Macs use that protocol. A few hundred more allow multiple Mac applications to talk to a single BlackBerry simultaneously, something that has not been possible till now.

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Under the hood KF 4.6 has moved from using ZDBase for its backing store, instead using a tuplebase. This makes it possible to split HTML page generation into separate processes, potentially running on multiple front end machines. It also restores support for a rich client application, now written in Java, using ZTSoup to efficiently communicate changes in the tuplebase, whether made by other clients or by the web interface.

It was thus relatively straightforward to implement ZFakeWindow_NSPlugin, which translates between the Netscape browser plugin and the ZFakeWindow APIs. What was actually more difficult was finding a decent implementation of the plugin glue code and header files. In 2002 there wasn't anything that would work with current compilers and with current browsers, so most of the effort was in putting together ZNSPlugin, which is a usable implementation of the glue.

ZooLib's tuplebase is derived from the tuplespace concept initially explored in the Linda coordination language, another well known derivation of which is Sun's JavaSpaces system. Whereas JavaSpaces is Java-only and relies on many of that languages's features, ZooLib's tuplebase works today with C++ and Java, and is well suited to work with other languages.

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ZooLib defines and implements a graphics API that produces identical results across all supported platforms. It is geared towards creating user interface elements and so is pixel-based rather than geometric so that a programmer can know precisely which pixels will be touched by a drawing operation. It supports pixel-plotting, lines of any thickness, text, rectangles, rounded rectangles, ovals, arbitrary regions and the drawing of masked-pixmaps. ZDC_ZooLib is an implementation of this API using no OS facilities at all, and thus can be used in server applications without the difficulties that normally poses (gaining access to a window or graphics server from a low-privilege process).

The implementation uses operations on ZBigRegion instances to decide which pixels to touch, decomposes the regions into rectangles and then calls ZDCPixmapBlit to actually do the work.

Applications often have to satisfy two conflicting requirements. On the one hand the data created by a user has a structure whose parts should be managed independently of one another, ideally with each piece placed in its own file. On the other hand users like to think of their data as a single entity which can be copied, emailed and backed up in its entirety. Although Mac OS X has the notion of a bundle, a specially marked directory which behaves like a single file when manipulated by the Finder, other operating systems do not.

Continue reading "BlockStore: File System in a File" »

I picked the name 'asset' as an alternative to 'resource', a term that already has too many disparate meanings on different platforms. That said, assets are used in the same situations that MacOS/Win32/BeOS resources would be, although the mechanism is more flexible.

The data making up an asset tree is directly usable by any processor, big or little-endian. It can be kept in a file, loaded into RAM, memory-mapped from disk or accessed from a stream.

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NPainter is a suite of classes that provides a MacPaint-like interface, but supporting indexed and true color, across all platforms supported by ZooLib.

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Fibers, at least in this context, are threads implemented using setjmp/longjmp to transfer control in a manner reminiscent of co-routines. They are a generalization of the stack-swapping used by NetPhone to run in the constrained environment it experienced when its deferred tasks were scheduled when an application with a tiny stack was current (yes Print Monitor, I'm talking about you).

Continue reading "ZFiber: Threads At Interrupt Time" »