elisp: Font and Color Parameters
28.4.3.8 Font and Color Parameters
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These frame parameters control the use of fonts and colors.
‘font-backend’
A list of symbols, specifying the “font backends” to use for
drawing fonts in the frame, in order of priority. On X, there are
currently two available font backends: ‘x’ (the X core font driver)
and ‘xft’ (the Xft font driver). On MS-Windows, there are
currently two available font backends: ‘gdi’ and ‘uniscribe’ (
(emacs)Windows Fonts). On other systems, there is only one
available font backend, so it does not make sense to modify this
frame parameter.
‘background-mode’
This parameter is either ‘dark’ or ‘light’, according to whether
the background color is a light one or a dark one.
‘tty-color-mode’
This parameter overrides the terminal’s color support as given by
the system’s terminal capabilities database in that this
parameter’s value specifies the color mode to use on a text
terminal. The value can be either a symbol or a number. A number
specifies the number of colors to use (and, indirectly, what
commands to issue to produce each color). For example,
‘(tty-color-mode . 8)’ specifies use of the ANSI escape sequences
for 8 standard text colors. A value of -1 turns off color support.
If the parameter’s value is a symbol, it specifies a number through
the value of ‘tty-color-mode-alist’, and the associated number is
used instead.
‘screen-gamma’
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.
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 ‘screen-gamma’, that means no correction is needed. Other
values request correction, designed to make the corrected colors
appear on your screen the 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
‘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.
‘alpha’
This parameter specifies the opacity of the frame, on graphical
displays that support variable opacity. It should be an integer
between 0 and 100, where 0 means completely transparent and 100
means completely opaque. It can also have a ‘nil’ value, which
tells Emacs not to set the frame opacity (leaving it to the window
manager).
To prevent the frame from disappearing completely from view, the
variable ‘frame-alpha-lower-limit’ defines a lower opacity limit.
If the value of the frame parameter is less than the value of this
variable, Emacs uses the latter. By default,
‘frame-alpha-lower-limit’ is 20.
The ‘alpha’ frame parameter can also be a cons cell ‘(ACTIVE .
INACTIVE)’, where ACTIVE is the opacity of the frame when it is
selected, and INACTIVE is the opacity when it is not selected.
The following frame parameters are semi-obsolete in that they are
automatically equivalent to particular face attributes of particular
faces ((emacs)Standard Faces):
‘font’
The name of the font for displaying text in the frame. This is a
string, either a valid font name for your system or the name of an
Emacs fontset (Fontsets). It is equivalent to the ‘font’
attribute of the ‘default’ face.
‘foreground-color’
The color to use for the image of a character. It is equivalent to
the ‘:foreground’ attribute of the ‘default’ face.
‘background-color’
The color to use for the background of characters. It is
equivalent to the ‘:background’ attribute of the ‘default’ face.
‘mouse-color’
The color for the mouse pointer. It is equivalent to the
‘:background’ attribute of the ‘mouse’ face.
‘cursor-color’
The color for the cursor that shows point. It is equivalent to the
‘:background’ attribute of the ‘cursor’ face.
‘border-color’
The color for the border of the frame. It is equivalent to the
‘:background’ attribute of the ‘border’ face.
‘scroll-bar-foreground’
If non-‘nil’, the color for the foreground of scroll bars. It is
equivalent to the ‘:foreground’ attribute of the ‘scroll-bar’ face.
‘scroll-bar-background’
If non-‘nil’, the color for the background of scroll bars. It is
equivalent to the ‘:background’ attribute of the ‘scroll-bar’ face.
Info Catalog
elisp: Cursor Parameters
elisp: Window Frame Parameters