FunctionPackage: cgToCDocOverviewCGDocRelNotesFAQIndexPermutedIndex
Allegro CL version 8.1
Unrevised from 8.0 to 8.1.
8.0 version

font-ascent

Arguments: struct

Returns the maximum height of a character from the baseline for the fontmetrics structure specified by the argument. This height measured in stream units of the stream associated with the argument, which must be a fontmetrics object.

There are font methods for the graphical-stream class (formerly called windows-graphics) and subclasses of it, for various dialog-item classes that display text, and for grid-subsection and outline-item.

The setf of this function may be called to set the current font of the object. The setf takes an additional optional argument called set-line-height-too. This is used only when the object is a graphical-stream (which includes windows and other objects on which drawing may be done). When true, the line-height of the stream is set to the font-height of the font. The default value is t; this is usually the appropriate value, so that newlines printed to the stream will advance the current y position as appropriate for this font. Therefore a font is typically set with a form such as this:

(setf (font my-window) (make-font-ex nil "Arial" 18))

though to avoid changing the window's line-height you could instead use this:

(setf (font my-window nil)(make-font-ex nil "Arial" 18))

The font of an object may also be set by passing a :font initarg when creating the object, and by calling with-font.

Regarding outline-items: while the font of an individual outline-item may be set, all of the items in the outline will retain the same height, which is the font-height of the font of the outline. For this reason, the font of an outline-item should not be taller than the general font of the outline, or else the text will be clipped.

See also Text and Fonts in cg-drawing.htm.


Copyright (c) 1998-2009, Franz Inc. Oakland, CA., USA. All rights reserved.
Documentation for Allegro CL version 8.1. This page was not revised from the 8.0 page.
Created 2009.7.29.

ToCDocOverviewCGDocRelNotesFAQIndexPermutedIndex
Allegro CL version 8.1
Unrevised from 8.0 to 8.1.
8.0 version