Some things just can't be done (or can't be done well) using calculations and custom functions. When you run into this situation, you may consider looking into plug-ins, which are tiny applications that live inside FileMaker to help it do some specific task that it can't do on its own.
Many plug-ins focus on doing certain things: process a credit card transaction; create charts; perform certain jobs based on a schedule; or interact with special devices like cameras, barcode readers and so on. Although plug-ins work through calculation functions, scripts, which the next section covers, generally control them.
Some plug-ins, though, are perfect candidates for calculations. Plug-ins can convert, resize, and otherwise modify images in container fields; or perform complex mathematical, scientific, or financial calculations that would be difficult or inefficient in a calculation. Although this book doesn't cover any specific plug-ins, this section shows you how to access the functions any plug-in you install provides.
12.2.1. Installing Plug-ins
A plug-in comes in a file bearing a special FileMaker Plug-in icon (shown in Figure 12-4). In order to use plug-ins, FileMaker needs to load them (that is, it has to put the plug-in code into its own memory). Every time you launch the program, it searches for plug-ins in a folder called Extensions inside its own folder, and loads all that it finds.
Installing a plug-in is thus a simple matter of making sure it's in the right folder:
Note: If you're using FileMaker Pro Advanced, the FileMaker folder is called FileMaker Pro 8 Advanced, not FileMaker Pro 8.
Once you've found the folder, just drag the plug-in file into it and restart FileMaker. You won't see anything on your screen to let you know it worked. To see which plug-ins FileMaker has actually loaded, you need to visit the application preferences (FileMaker Pro images/U2192.jpg border=0> Preferences on Mac OS X, Edit images/U2192.jpg border=0> Preferences on Windows). In the Preferences window, click the Plug-ins tab, or look to Figure 12-5.
Once you've installed plug-ins, you can use their functions from the External functions section of the list in the Specify Calculation dialog box (Section 9.2). For details on how to use these functions, consult their developer's manuals or Web sites.
12.2.2. Old and New Plug-ins
There are actually two kinds of plug-ins for FileMaker: older FileMaker 4-style plug-ins and newer FileMaker 7/8-style plug-ins. FileMaker 8 works with both types of plug-ins, but it's a good idea to ask your plug-in provider which type you're getting, since the FileMaker 4 plug-ins have limited abilities:
FileMaker 7/8 plug-ins give you a lot more options. Functions can have as many parameters as their creator cares to give them. They can also deal with all data types, including pictures, movies, and files stored in container fields.
12.2.3. Finding Plug-ins
Most FileMaker developers lack the know-how to build their own plug-ins. Although you can hire a programmer to make one to your specifications, you can often find one on the market that already does what you want. To help you hunt them down, FileMaker, Inc. has a plug-in registry on its Web site. Just visit www.filemaker.com/plugins/index.html to access the site.
You can also visit the more prolific FileMaker plug-in vendors' Web sites:
New vendors come up with great products all the time. Use your favorite search engine or try FileMaker's Web site for new plug-ins:
12.2.4. Creating Your Own Plug-ins
If you're feeling adventurous (or have helpful programmer friends), you can create your own plug-ins. To do that, you first need FileMaker Advanced (it's the only version of FileMaker that includes the Plug-in Software Development Kit or SDK). You also need a C++ development environment. In Windows, you're best off with Visual C++ or Visual Studio.NET. On Mac OS X, you can use CodeWarrior (www.codewarrior.com) or XCode (included with Mac OS X 10.3). The Plug-in SDK includes sample projects for each of these environmentsand sample plug-in codeto get you started.
Part I: Introduction to FileMaker Pro
Your First Database
Organizing and Editing Records
Building a New Database
Part II: Layout Basics
Advanced Layouts and Reports
Part III: Multiple Tables and Relationships
Multiple Tables and Relationships
Advanced Relationship Techniques
Part IV: Calculations
Introduction to Calculations
Calculations and Data Types
Part V: Scripting
Part VI: Security and Integration
Exporting and Importing
Sharing Your Database
Part VII: Appendixes
Appendix A. Getting Help