19.17 Customization of Display

This section describes variables (see section Variables) that you can change to customize how Emacs displays. Beginning users can skip it.

If the variable inverse-video is non-nil, Emacs attempts to invert all the lines of the display from what they normally are.

If the variable visible-bell is non-nil, Emacs attempts to make the whole screen blink when it would normally make an audible bell sound. This variable has no effect if your terminal does not have a way to make the screen blink.

The variable echo-keystrokes controls the echoing of multi-character keys; its value is the number of seconds of pause required to cause echoing to start, or zero, meaning don't echo at all. The value takes effect when there is someting to echo. See section The Echo Area.

The variable baud-rate holds the output speed of the terminal, as far as Emacs knows. Setting this variable does not change the speed of actual data transmission, but the value is used for calculations. On text-only terminals, it affects padding, and decisions about whether to scroll part of the screen or redraw it instead. It also affects the behavior of incremental search.

On graphical displays, baud-rate is only used to determine how frequently to look for pending input during display updating. A higher value of baud-rate means that check for pending input will be done less frequently.

On graphical display, Emacs can optionally display the mouse pointer in a special shape to say that Emacs is busy. To turn this feature on or off, customize the group cursor. You can also control the amount of time Emacs must remain busy before the busy indicator is displayed, by setting the variable hourglass-delay.

On graphical display, this variables specifies the vertical position of an overline above the text, including the height of the overline itself (1 pixel). The default value is 2 pixels.

On graphical display, Emacs normally draws an underline at the baseline level of the font. If x-underline-at-descent-line is non-nil, Emacs draws the underline at the same height as the font's descent line.

On some text-only terminals, bold face and inverse video together result in text that is hard to read. Call the function tty-suppress-bold-inverse-default-colors with a non-nil argument to suppress the effect of bold-face in this case.

On a text-only terminal, when you reenter Emacs after suspending, Emacs normally clears the screen and redraws the entire display. On some terminals with more than one page of memory, it is possible to arrange the termcap entry so that the ‘ti’ and ‘te’ strings (output to the terminal when Emacs is entered and exited, respectively) switch between pages of memory so as to use one page for Emacs and another page for other output. On such terminals, you might want to set the variable no-redraw-on-reenter non-nil; this tells Emacs to assume, when resumed, that the screen page it is using still contains what Emacs last wrote there.