These frame parameters control the use of fonts and colors.
font-backendA list of symbols, specifying the font backends to use for
drawing characters on the frame, in order of priority. In Emacs built
without Cairo drawing on X, there are currently three potentially
available font backends: x (the X core font driver), xft
(the Xft font driver), and xfthb (the Xft font driver with
HarfBuzz text shaping). If built with Cairo drawing, there are also
three potentially available font backends on X: x, ftcr
(the FreeType font driver on Cairo), and ftcrhb (the FreeType
font driver on Cairo with HarfBuzz text shaping). When Emacs is built
with HarfBuzz, the default font driver is ftcrhb, although use
of the ftcr driver is still possible, but not recommended. On
MS-Windows, there are currently three available font backends:
gdi (the core MS-Windows font driver), uniscribe (font
driver for OTF and TTF fonts with text shaping by the Uniscribe
engine), and harfbuzz (font driver for OTF and TTF fonts with
HarfBuzz text shaping) (see Windows Fonts in The GNU Emacs
Manual). The harfbuzz driver is similarly recommended. On
Haiku, there can be several font drivers (see Haiku Fonts in The GNU Emacs Manual).
On other systems, there is only one available font backend, so it does not make sense to modify this frame parameter.
background-modeThis 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.
Some window systems do not support the alpha parameter for child
frames (see Child Frames).
alpha-background ¶Sets the background transparency of the frame. Unlike the alpha
frame parameter, this only controls the transparency of the background
while keeping foreground elements such as text fully opaque. It
should be an integer between 0 and 100, where 0 means
completely transparent and 100 means completely opaque (default).
The following frame parameters are semi-obsolete in that they are automatically equivalent to particular face attributes of particular faces (see Standard Faces in The Emacs Manual):
fontThe 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 (see Fontsets). It is equivalent to the font
attribute of the default face.
foreground-colorThe color to use for characters. It is equivalent to
the :foreground attribute of the default face.
background-colorThe color to use for the background of characters. It is equivalent to
the :background attribute of the default face.
mouse-colorThe color for the mouse pointer. It is equivalent to the :background
attribute of the mouse face.
cursor-colorThe color for the cursor that shows point. It is equivalent to the
:background attribute of the cursor face.
border-colorThe color for the border of the frame. It is equivalent to the
:background attribute of the border face.
scroll-bar-foregroundIf non-nil, the color for the foreground of scroll bars. It is
equivalent to the :foreground attribute of the
scroll-bar face.
scroll-bar-backgroundIf non-nil, the color for the background of scroll bars. It is
equivalent to the :background attribute of the
scroll-bar face.