Apple 12/640PS manual Bitmapped fonts

Bitmapped fonts

Bitmapped fonts consist of “pictures” of a typeface at specific sizes. For example, you might have bitmapped fonts at 10-, 12-, and 18-point sizes installed in your Mac OS computer. For best results you need a separate font file for each size of character you want to use.

The icon of a bitmapped font (also called a fixed-size font or screen font) has the single letter A on it. The font’s point size appears at the end of its name.

When you request a bitmapped character, your computer looks for an installed bitmapped font in the size you specified. (See “How the Mac OS Computer Looks for Fonts,” later in this appendix.) If it can’t find that font, your computer tries to construct one by scaling a size that it does find.

In most cases, scaled bitmapped fonts don’t look nearly as good as preinstalled ones. Such scaling is one reason for the jagged edges (sometimes called “jaggies”) you’ll see on your screen or in a printed document when you request an uninstalled size (for example, 17-point Geneva).

Bitmapped fonts are designed on grids of 72 dots per inch (dpi)—the standard Mac OS screen resolution. Because of their correspondence to the standard screen resolution, bitmapped fonts in preinstalled sizes always look great on your display.

When you print a bitmapped font, it prints at a resolution of 72 dpi. Because most modern printers can print at resolutions far better than this (your LaserWriter 12/640 PS prints at 600 dpi), printed bitmapped fonts almost always have jagged edges or stairstep sides.

Fortunately, the Mac OS can use bitmapped fonts in combination with other font formats, reserving bitmaps for the screen and other kinds of fonts for the printer.

330Appendix C