# Multiplatform User Interface Guidelines

Use the following guidelines to ensure that your user interfaces are supported across multiple platforms.

- Function panel (.fp) files are portable across platforms.
- User Interface Resource (.uir) files are portable across platforms.
- Image file formats other than PCX (.pcx) and JPG (.jpg) are not portable.
- Color hue and intensity differences between platforms are unavoidable.
- The only fonts sure to be available on all platforms are the National Instruments fonts. National Instruments fonts of the same name resemble each other stylistically from one platform to another, although some relative size differences might exist. The National Instruments Meta Fonts are of uniform size, or height, relative to the rest of the user interface and are the most portable family of fonts available. However, the width of the National Instruments Meta Fonts might differ slightly from one platform to another. Allow for extra space in the width of all control labels to assure consistent appearance.
  You might find the User Interface library functions GetCtrlBoundingRect, GetTextDisplaySize, and GetScreenSize useful in calculating and compensating for font size discrepancies between platforms.
- The order in which LabWindows/CVI processes user interface events might differ between Windows and UNIX platforms. This happens because of differences between the underlying window management systems that LabWindows/CVI uses.
- Do not assign the forward <Delete> key as a hot-key in your user interface, because that key does not exist on all platforms.