Overview of Fonts in IDL

IDL uses three font systems for writing characters on the graphics device: Hershey (vector) fonts, TrueType (outline) fonts, and device (hardware) fonts. This chapter describes each of the three types of fonts, discusses when to use each type, and explains how to use fonts when creating graphical output in IDL.

Hershey Vector Fonts

Hershey vector-drawn fonts, also referred to as Hershey fonts, are drawn as lines. They are device-independent (within the limits of device resolution) and can be used in Direct Graphic and Object Graphic displays. All Hershey vector fonts included with IDL are guaranteed to be available in any IDL installation. See About Hershey Vector Fonts for additional details.

TrueType Fonts

TrueType fonts, also referred to here as outline fonts, are drawn as character outlines, which are filled when displayed. They are largely device-independent, but do have some device-dependent characteristics. Four TrueType font families are included with IDL; these fonts should display in a similar way on any IDL platform. TrueType font support for IDL Object Graphics was introduced in IDL version 5.0 and support in IDL Direct Graphics was introduced in IDL version 5.1. See About TrueType Fonts for additional details.

Device Fonts

Device fonts, also referred to as hardware fonts, rely on character-display hardware or software built in to a specific display device, and include PostScript fonts. Device fonts, necessarily, are device-dependent and differ from platform to platform and display device to display device. Device fonts are supported in IDL Direct Graphics. See About Device Fonts for additional details.