One of the things that sets FileMaker apart from other database applications is that it runs on both Windows and Macintosh operating systems. You can even have a mixed platform of client machines. If you are developing a system that needs to run on both platforms, there are a few design considerations you'll need to keep in mind.
First, text blocks may be rendered slightly differently between platforms because of differences in the dots per inch (dpi) that each supports. Macintosh operating systems use 72 dpi, whereas Windows is built at 96 dpi. Font sizes are always described as 72nds of an inch regardless of platform, which means that a 12point font takes up 12 pixels (12/72nds of 72) on a Macintosh monitor, but 16 pixels on a Windows monitor (12/72nds of 96). In either case, this represents 1/6th of an inch.
The problem is that graphics and other layout objects are set to be a precise number of pixels tall and wide. If, for instance, you have a text block or field on a layout that's set to be 72 pixels wide, you'd be able to see fewer characters in that space on Windows. To account for this situation, you should make text blocks and buttons slightly oversized so that you don't truncate characters on Windows.
Not all fonts available on one platform are supported on the other; platform-specific fonts should be avoided. Some fonts display different baselines on Mac and PC. Trebuchet, for example, is a particularly bad culprit. The text baseline determines where the bottom of a font appears within a text block. Different baselines may mean that letters that hang below the baseline (such as g, y, j, p) have their tails cut off. Verdana tends not to be so bad, but it's a wide font and may consume too much horizontal space in a database. Lucinda is often a fairly safe font, if it is available to all your users. Tahoma also is fairly consistent between platforms. The combination of font and field box size is tricky, and you'll just have to experiment. Note that 10point Verdana with a 16pixel field height tends to work well on both platforms, but it's a very wide font. Use Arial/Helvetica if you're pressed for space.
The other big cross-platform layout problem is the viewable size of your layouts. It's generally desirable to create layouts on which users won't need to scroll to see important information. Different operating systems, even within a platform, may have different viewable layout areas, even at the same monitor resolutions. The problem is compounded by users who position their Dock or Start menu bar in different places. Windows XP tends to be the "piggiest" consumer of screen real estate and represents your lowest common denominator for a given resolution.
In the end, of course, the best advice when developing cross-platform applications is simply to test everything early in your development process on all operating systems you plan to support.
We also strongly urge you to create a template layout in which all your fonts have been selected, your field sizes established, and layout size and window size set. Then rather than having to carefully duplicate these standards across your solution, simply start all new layouts by duplicating this template.
Part I: Getting Started with FileMaker 8
Using FileMaker Pro
Defining and Working with Fields
Working with Layouts
Part II: Developing Solutions with FileMaker
Relational Database Design
Working with Multiple Tables
Working with Relationships
Getting Started with Calculations
Getting Started with Scripting
Getting Started with Reporting
Part III: Developer Techniques
Developing for Multiuser Deployment
Advanced Interface Techniques
Advanced Calculation Techniques
Advanced Scripting Techniques
Advanced Portal Techniques
Debugging and Troubleshooting
Converting Systems from Previous Versions of FileMaker Pro
Part IV: Data Integration and Publishing
Importing Data into FileMaker Pro
Exporting Data from FileMaker
Instant Web Publishing
FileMaker and Web Services
Custom Web Publishing
Part V: Deploying a FileMaker Solution
Deploying and Extending FileMaker
FileMaker Server and Server Advanced
Documenting Your FileMaker Solutions