Apple 12/640PS Technické informace stáhnout pdf (Strana 295)

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–based 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

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.

296

Appendix C

1 2 ... 290 291 292 293 294 295 296 297 298 299 300 ... 353 354

Žádné komentáře

Apple 12/640PS Technické informace Strana 295