FbTerm(1)
NAME
FbTerm - a fast Frame Buffer based TERMinal emulator for linux
SYNOPSIS
fbterm [options] [--] [command [arguments]]
DESCRIPTION
- FbTerm is a fast terminal emulator for linux with frame buffer device
or VESA video card. Features include:
- * mostly as fast as terminal of linux kernel while accelerated
- scrolling is enabled
- * select font with fontconfig and draw text with freetype2, same as
- Qt/Gtk+ based GUI apps
- * dynamically create/destroy up to 10 windows initially running
- default shell
- * record scroll-back history for every window
* auto-detect current locale and convert text encoding, support dou - ble width scripts like Chinese, Japanese etc
- * switch between configurable additional text encodings with hot keys
- on the fly
- * copy/past selected text between windows with mouse when gpm server
- is running
- * change the orientation of screen display, a.k.a. screen rotation
* lightweight input method framework with client-server architecture * background image for eye candy
OPTIONS
command [arguments] may be given to override the built-in choice of
shell program. Normally FbTerm checks the SHELL variable. If that is
not set, it tries to use the user's login shell program specified in
the password file. If that is not set, /bin/sh will be used. You should
use the -- argument to separate FbTerm's options from the arguments
supplied to the command.
FbTerm first uses option value specified in command line arguments,
then in the configure file $HOME/.fbtermrc. If that file doesn't
exist, FbTerm will create it with default options on startup.
- -h, --help
- display the help and exit
- -V, --version
- display FbTerm version and exit
- -v, --verbose
- display extra FbTerm's information
- -n, --font-names=text
- specify font family names
- -s, --font-size=num
- specify font pixel size
- --font-width=num
- force font width
- --font-height=num
- force font height
- -f, --color-foreground=num
- specify foreground color
- -b, --color-background=num
- specify background color
- -e, --text-encodings=text
- specify additional text encodings
- -r, --screen-rotate=num
- specify the orientation of screen display
- -i, --input-method=text
- specify input method program
- --cursor-shape=num
- specify default cursor shape
- --cursor-interval=num
- specify cursor flash interval
- --vesa-mode=num
- specify VESA video mode
- --vesa-mode=list
- display available VESA video modes
- see comments in $HOME/.fbtermrc for details of these options.
SHORTCUT SUMMARY
- keyboard:
- CTRL_ALT_E: exit from FbTerm
CTRL_ALT_C: create a new window
CTRL_ALT_D: destroy current window
CTRL_ALT_1: switch to window 1
CTRL_ALT_2: switch to window 2
CTRL_ALT_3: switch to window 3
CTRL_ALT_4: switch to window 4
CTRL_ALT_5: switch to window 5
CTRL_ALT_6: switch to window 6
CTRL_ALT_7: switch to window 7
CTRL_ALT_8: switch to window 8
CTRL_ALT_9: switch to window 9
CTRL_ALT_0: switch to window 10
SHIFT_LEFT: switch to previous window
SHIFT_RIGHT: switch to next window
SHIFT_PAGEUP: history scroll up
SHIFT_PAGEDOWN: history scroll down
CTRL_ALT_F1: switch to encoding of current locale
CTRL_ALT_F2 to CTRL_ALT_F6: switch to additional encodings
CTRL_SPACE: toggle input method - mouse:
- move when left button down: select text
double click with left button: auto select text
click with right button: paste selected text - Sometimes above actions will not work, please try to redo them with shift key holding down.
FRAME BUFFER DEVICE
Before executing FbTerm, make sure there is a frame buffer device in your system, and you have read/write access right with it. Normally FbTerm tries to open /dev/fb0 and /dev/fb/0, environment variable "FRAMEBUFFER" may be used to override this built-in behavior.
VESA VIDEO DEVICE
From version 1.6, FbTerm adds VESA video card support. By default,
FbTerm tries frame buffer device first, if failure, then tries to use
VESA device with highest resolution and color depth. option "vesa-mode"
may be given to force only open VESA device with the specified video
mode. To see available video modes for your VESA card, execute "fbterm
--vesa-mode=list".
Attention: 1) VESA support requires root privilege to work; 2) do not
force to use VESA device on the system with frame buffer device
enabled, they maybe conflict with each other.
FONT
FbTerm invokes fontconfig to get a font list, if the first font doesn't
contain the glyph for the rendering character, it will try second font,
then the third, ... and so on, user can see this ordered font list with
"fbterm -v".
If you don't like the fonts selected by FbTerm, execute "fc-list" to
get available fonts, choose favorites as the value of option "fontnames". You may also modify the configure file of fontconfig, which
will change the behavior of all programs based on fontconfig!
TEXT ENCODING
By using iconv, FbTerm converts other encodings to internal encoding
UTF-8. On startup, FbTerm checks variable LC_CTYPE to determine the
default text encoding, which is binded to shortcut CTRL_ALT_F1. User
can specify up to 5 additional encodings with option "text-encodings",
for example, as a Chinese user, you set "text-encodings=gbk,big5",
shortcut CTRL_ALT_F2 will bind to gbk, and CTRL_ALT_F3 bind to big5.
BACKGROUND IMAGE
- FbTerm doesn't load and parse any image file with various formats directly, instead it takes a screen shot of frame buffer device on startup if variable FBTERM_BACKGROUND_IMAGE is defined, then uses this screen shot as the background for text rendering. In order to enable background image support, user should first put a image to frame buffer device with a image viewer. A wrapper script using fbv is listed below:
- #!/bin/bash
- # fbterm-bi: a wrapper script to enable background image with
- fbterm
- # usage: fbterm-bi /path/to/image fbterm-options
- echo -ne "\e[?25l" # hide cursor
- fbv -ciuker "$1" << EOF
q
EOF - shift
export FBTERM_BACKGROUND_IMAGE=1 exec fbterm "$@" - Attention: 1) do not enable background image on frame buffer device with 8bpp depth, because FbTerm changes color map table for correct text rendering; 2) if the screen shot is different from the original image, try to use a fast scrolling disabled frame buffer device.
INPUT METHOD
Instead of adding input method directly in FbTerm, a client-server
based input method framework is designed to do this work. FbTerm acts
as a client, standalone IM program as a server, and they run in separated processes.
As a normal IM user, you should have a IM program written for FbTerm,
and specify it as the value of option "input-method". CTRL_SPACE is
the shortcut to activate/deactivate input method.
SECURITY NOTES
FbTerm tries to change linux kernel key map table to setup shortcuts,
which requires SYS_TTY_CONFIG capability from kernel version 2.6.15. It
means FbTerm should be a setuid 0 program to allow non-root users to
use shortcuts. FbTerm only switches to root privilege temporarily when
changing key map table, we believe it's pretty much free from security
problems.
If you really don't like this and not use VESA support, and have a linux kernel with file system capabilities enabled, which allow user to give binaries a subset of root's powers without using setuid 0 (official kernel 2.6.27 includes it), you can run command "sudo setcap 'cap_sys_tty_config+ep' /path/to/fbterm".
PERFORMANCE
- According test result, FbTerm spends more than 95% time on painting
screen. Speedup painting will significantly increase performance. Here
are some suggestions for frame buffer device:
- * Enable fast scrolling on frame buffer device. The visible screen
- will be just a window of the video memory, when scrolling, FbTerm only change the start of window, no need to repaint the whole screen.
* On Intel P6 family processors the Memory Type Range Registers- (MTRRs) may be used to control processor access to memory ranges. If you have video card on a PCI or AGP bus, enabling write-combining allows bus write transfers to be combined into a larger transfer before bursting over the PCI/AGP bus. This can increase performance of FbTerm's paint operations.
- Maybe you need to enable them manually for your video card. For example, by default fast scrolling and write-combining are all disabled on general VESA frame buffer device, GRUB/LILO configure file should be modified to enable them. A GRUB example is showed below:
- title Ubuntu
- root (hd0,0)
kernel /boot/vmlinuz ro root=LABEL=UBUNTU splash vga=0x317 - video=vesafb:ywrap,mtrr:3
- initrd /boot/initrd.img
- You may check fast scrolling status with "fbterm -v", a message with "scrolling: redraw" means fast scrolling is disabled, otherwise enabled.
AUTHOR
Written by dragchan.
REPORTING BUGS
Please submit bug reports to <http://code.google.com/p/fbterm/issues>.
COPYRIGHT
- Copyright (C) 2008-2009 dragchan. License GPLv2: GNU GPL version 2 or
later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.