@c -*-texinfo-*-
@c This is part of the GNU Emacs Lisp Reference Manual.
-@c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998, 1999
+@c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998, 1999, 2002
@c Free Software Foundation, Inc.
@c See the file elisp.texi for copying conditions.
@setfilename ../info/frames
the frame appear with the wrong ones and then change to the specified
ones. If that bothers you, you can specify the same geometry and
appearance with X resources; those do take effect before the frame is
-created. @xref{Resources X,, X Resources, emacs, The GNU Emacs Manual}.
+created. @xref{X Resources,, X Resources, emacs, The GNU Emacs Manual}.
X resource settings typically apply to all frames. If you want to
specify some X resources solely for the sake of the initial frame, and
@code{box}, and @code{(bar . @var{width})}. The symbol @code{box}
specifies an ordinary black box overlaying the character after point;
that is the default. The symbol @code{bar} specifies a vertical bar
-between characters as the cursor. @code{(bar . @var{width})} specifies
-a bar @var{width} pixels wide.
+between characters as the cursor. @code{(bar . @var{width})}
+specifies a bar @var{width} pixels wide. The symbol @code{hbar}
+specifies a horizontal bar, an underscore-like cursor. @code{(hbar .
+@var{width})} specifiles a horizontal bar @var{width} pixels high.
@vindex cursor-type
The buffer-local variable @code{cursor-type} overrides the value of
@item screen-gamma
@cindex gamma correction
-If this is a number, Emacs performs ``gamma correction'' on colors. The
-value should be the screen gamma of your display, a floating point
-number. Usual PC monitors have a screen gamma of 2.2, so the default is
-to display for that gamma value. Specifying a smaller value results in
-darker colors, which is desirable for a monitor that tends to display
-colors too light. A screen gamma value of 1.5 may give good results for
-LCD color displays.
+If this is a number, Emacs performs ``gamma correction'' which adjusts
+the brightness of all colors. The value should be the screen gamma of
+your display, a floating point number.
+
+Usual PC monitors have a screen gamma of 2.2, so color values in
+Emacs, and in X windows generally, are calibrated to display properly
+on a monitor with that gamma value. If you specify 2.2 for
+@code{screen-gamma}, that means no correction is needed. Other values
+request correction, designed to make the corrected colors appear on
+your screen they way they would have appeared without correction on an
+ordinary monitor with a gamma value of 2.2.
+
+If your monitor displays colors too light, you should specify a
+@code{screen-gamma} value smaller than 2.2. This requests correction
+that makes colors darker. A screen gamma value of 1.5 may give good
+results for LCD color displays.
@item tool-bar-lines
The number of lines to use for the toolbar. A value of @code{nil} means
variable to some other string, around a call to @code{x-get-resource}.
@end defvar
- @xref{Resources X,, X Resources, emacs, The GNU Emacs Manual}.
+ @xref{X Resources,, X Resources, emacs, The GNU Emacs Manual}.
@node Display Feature Testing
@section Display Feature Testing
(All color displays can do this.)
@end defun
+@anchor{Display Face Attribute Testing}
+@defun display-supports-face-attributes-p attributes &optional display
+@tindex display-supports-face-attributes-p
+This function returns non-@code{nil} if all the face attributes in
+@var{attributes} are supported (@pxref{Face Attributes}).
+
+The definition of `supported' is somewhat heuristic, but basically
+means that a face containing all the attributes in @var{attributes},
+when merged with the default face for display, can be represented in a
+way that's
+
+@enumerate
+@item
+different in appearance than the default face, and
+
+@item
+`close in spirit' to what the attributes specify, if not exact.
+@end enumerate
+
+Point (2) implies that a @code{:weight black} attribute will be
+satisfied by any display that can display bold, as will
+@code{:foreground "yellow"} as long as some yellowish color can be
+displayed, but @code{:slant italic} will @emph{not} be satisfied by
+the tty display code's automatic substitution of a `dim' face for
+italic.
+@end defun
+
@defun display-selections-p &optional display
@tindex display-selections-p
This function returns @code{t} if @var{display} supports selections.