qe-doc.texi

\input texinfo @c -*- texinfo -*-

@settitle QEmacs Documentation
@titlepage
@sp 7
@center @titlefont{QEmacs Documentation}
@sp 3
@end titlepage


@chapter Introduction
QEmacs (for Quick Emacs) is a very small but powerful
UNIX editor. It has features that even big editors lack :
@itemize

@item Full screen editor with an Emacs look and feel with all Emacs common
  features: multi-buffer, multi-window, command mode, universal
  argument, keyboard macros, config file with C like syntax, minibuffer
  with completion and history.

@item Can edit files of hundreds of Megabytes without being slow by using
  a highly optimized internal representation and by mmaping the file.

@item Full @emph{Unicode} support, including multi charset handling 
  (8859-x, UTF8, SJIS, EUC-JP, ...) and bidirectional editing respecting
  the Unicode bidi algorithm. Arabic and Indic scripts handling (in
  progress).

@item WYSIWYG @emph{HTML/XML/CSS2} mode graphical editing. Also supports lynx like
rendering on VT100 terminals.

@item WYSIWYG @emph{DocBook} mode based on XML/CSS2 renderer.

@item C mode: coloring with immediate update. Emacs like auto-indent.

@item Shell mode: colorized VT100 emulation so that your shell work
  exactly as you expect. Compile mode with next/prev error. 

@item Input methods for most languages, including Chinese (input methods
  come from the Yudit editor). 

@item @emph{Hexadecimal editing} mode with insertion and block commands. Unicode
  hexa editing is also supported.

@item Works on any VT100 terminals without termcap. UTF8 VT100 support
  included with double width glyphs.

@item X11 support. Support multiple proportionnal fonts at the same time
  (as XEmacs). X Input methods supported. Xft extension supported for
  anti aliased font display.

@item 
  Small! Full version (including HTML/XML/CSS2/DocBook rendering and all
  charsets): 200KB big. Basic version (without bidir/unicode
  scripts/input/X11/C/Shell/HTML/dired): 49KB.

@end itemize

@chapter Invocation

@example
usage: qe [-h] [-nw] [-display display] [-geometry WxH] 
          [-fs ptsize] [filename...]
@end example

@table @samp

@item -h
show help

@item -nw
force tty terminal usage

@item -display display
set X11 display to 'display'

@item -geometry WxH
set X11 display size

@item -fs ptsize
set default font size

@end table

When invoked as
@example
usage: ffplay 
@end example

QEmacs goes to @code{dired} mode automatically so that you can browse your
files easily (same as @kbd{C-x C-d} key).

@chapter Common editing commands

@section Concepts

QEmacs store file content in @dfn{buffers}. Buffers can be seen as big
arrays of bytes.

An @dfn{editing mode} tells how to display the content of a buffer and
how to interact with the user to modify its content.

Multiple @dfn{Windows} can be shown on the screen at the same time. Each
windows show the content of a buffer with an editing mode. It means that
you can open several windows which show the same buffer in different
modes (for example, both text and hexadecimal).

Each key binding activates a @dfn{command}. You can directly execute a
command by typing @kbd{M-x command RET}.

Commands can take arguments. The key binding @kbd{C-u N} where N is an
optional number is used to give a numeric argument to the commands which
can handle them. If the command cannot handle a numerical argument, it
is simply repeated @code{N} times.

@section Help

You can press @kbd{C-h b} to have the list of all the currently active
bindings, including the ones of the current editing mode.

@example
C-h C-h, F1             : help-for-help
C-h b                   : describe-bindings
C-h c                   : describe-key-briefly
@end example

@section Simple commands

@example
default                 : self-insert-command
C-p, up                 : previous-line
C-n, down               : next-line
C-b, left               : backward-char
C-f, right              : forward-char
M-b, C-left             : backward-word
M-f, C-right            : forward-word
M-v, prior              : scroll-down
C-v, next               : scroll-up
home, C-a               : beginning-of-line
end, C-e                : end-of-line
insert                  : overwrite-mode
C-d, delete             : delete-char
backspace               : backward-delete-char
M-<, C-home             : beginning-of-buffer
M->, C-end              : end-of-buffer
C-i                     : tabulate
C-q                     : quoted-insert
RET                     : newline
M-{                     : backward-paragraph
M-}                     : forward-paragraph
@end example

@section Region handling

@example
C-k                     : kill-line
C-space                 : set-mark-command
C-w                     : kill-region
M-w                     : copy-region
C-y                     : yank
M-y                     : yank-pop
C-x C-x                 : exchange-point-and-mark
@end example

@section Buffer and file handling

@example
C-x C-s                 : save-buffer
C-x C-w                 : write-file
C-x C-c                 : suspend-emacs
C-x C-f                 : find-file
C-x C-v                 : find-alternate-file
C-x b                   : switch-to-buffer
C-x k                   : kill-buffer
C-x i                   : insert-file
C-x C-q                 : vc-toggle-read-only
C-x C-b                 : list-buffers
@end example

@section Search and replace

@example
C-s                     : isearch-backward
C-r                     : isearch-forward
M-%                     : query-replace
@end example

@section Command handling

@example
M-x                     : execute-extended-command
C-u                     : universal-argument
C-g                     : abort
C-x u, C-_              : undo
C-x (                   : start-kbd-macro
C-x )                   : end-kbd-macro
C-x e                   : call-last-kbd-macro
@end example

@section Window handling

@example
C-x o                   : other-window
C-x 0                   : delete-window
C-x 1                   : delete-other-windows
C-x 2                   : split-window-vertically
C-x 3                   : split-window-horizontally
C-x f                   : toggle-full-screen
@end example

@section International

@example
C-x RET f               : set-buffer-file-coding-system
C-x RET b               : toggle-bidir
C-x RET C-\             : set-input-method
C-\                     : switch-input-method
@end example

@section Miscellaneous

@example
C-l                     : refresh
M-g                     : goto-line
M-q                     : fill-paragraph
C-x RET l               : toggle-line-numbers
C-x RET t               : truncate-lines
C-x RET w               : word-wrap
C-x C-e                 : compile
C-x C-p                 : previous-error
C-x C-n                 : next-error
C-x C-d                 : dired
@end example

@chapter Configuration file and resources

@section Resource path

All resources and configuration files are looked in the following paths:
@file{/usr/share/qe:/usr/local/share/qe:/usr/lib/qe:/usr/local/lib/qe:~/.qe}

@section Configuration file

QEmacs tries to load a configuration file in @file{~/.qe/config}. Each
line of the configuration file is a QEmacs command with a C like syntax
('-' in command name can be replaced by '_'). 

Read the example file @file{config.eg} to have some examples.

The following commands are useful:

@table @code
@item global_set_key(key, command)
Set a global key binding to a command.

@item set_display_size(width, height)
(X11) Set the window size, in character cells.

@item set_system_font(family, system_fonts)

(X11) Maps a system font to a QEmacs font family. Multiple fonts can be
given as fallback (@xref{fonts}).

@item set_style(stylename, css_property, css_value)
Set a colorization style (see @file{qestyle.h} and @file{config.eg} for
common style names)

@end table

@section Plugins

Any @file{.so} file found in the qemacs resource paths is considered as
a @dfn{plugin}. It is a piece of code containing new features for
qemacs. 

Currently, no plugins are compiled in, but you can look at the
@file{plugin-example/} directory to learn how to make one.

Most QEmacs object files can in fact be compiled either as a plugin or
be statically linked in qemacs. The plugin system is strongly inspirated
from the Linux Kernel 2.4 module system.

@chapter Internationalization

@section Charsets

QEmacs supports many common charsets including UTF8, shift JIS and EUC-JP. A
charset can be selected for each buffer with @kbd{C-x RET f}
(@code{set-buffer-file-coding-system}).

Currently, QEmacs automatically detects the UTF8 encoding. 

Note that unlike in other editors, changing the charset of a buffer
does not modify its content: buffers always contain bytes, and the charset
is only used when the buffer content may be converted to characters, for
example to display it on screen.  

You can use the UniHex editing mode (@kbd{M-x unihex-mode}) to see the
Unicode values of each character in your file with the associated byte
offset.

The command @code{convert-buffer-file-coding-system} can be used to
convert the buffer @emph{content} to another charset.

@section Input methods

The current input method can be changed with @kbd{C-x RET \}
(@code{set-input-method}). You can switch between this input method and
the default one with 'C-\'. 

The input methods are currently stored in the resource file @file{kmaps}.
They are extracted from the @emph{Yudit} editor keyboard maps.

@section Bidirectional editing

QEmacs fully supports the Unicode bidi algorithm. 

By default, in text editing mode, qemacs is not in bidirectionnal mode (it
may change soon). You can use 'C-x RET b' to toogle between bidi and normal
editing modes.

In HTML editing mode, bidi is always activated and all the CSS2 bidi
properties are supported.

@section Unicode scripts

Currently, QEmacs fully supports Arabic shapping. Devanagari shaping is on
the way. 

The resource file @file{ligatures} contains all the standard Unicode rules
to handle character modifiers such as accents. It means that even if your
font does not support the Unicode character modifiers, QEmacs will do its
best to handle them.

@chapter Editing Modes

@section C mode

This mode is currently activated by @samp{M-x c-mode}. It is
activated automatically when a C file is loaded.

@section Hexadecimal, ascii and unihex modes


Unlike other editors, QEmacs has powerful hexadecimal editing modes: all
common commands are working these modes, including the block commands. 

The hexadecimal mode (@kbd{M-x hex-mode}) shows both the hexa decimal
and ascii (bytes) values. You can toggle between the hexa and ascii columns
with 'TAB'.

The ascii mode (@kbd{M-x ascii-mode}) only shows the ascii column.

The unihex mode (@kbd{M-x unihex-mode}) shows both the unicode and
glyph associated to each @emph{character} of the buffer by using the current
buffer charset.

You can change the line width in these modes with 'C-left' and 'C-right'.

@section shell mode

You can activate it with @kbd{M-x shell}. Unlike other editors, a very
complete colorized VT100 emulation is done [it means you can launch
qemacs in the qemacs shell :-)].

By default, @dfn{interactive mode} is selected. It means that most keys
you type are transmitted to the shell. This way, you can use the shell
completion and editing functions. By pressing @kbd{C-o}, you toggle
between interactive and editing mode. In editing mode, you can editing
the shell buffer as any other buffer.

@section Dired mode

You can activate it with @kbd{C-x C-d}. You can open the selected
directory with @kbd{RET} or @kbd{right}. @kbd{left} is used to go to the
parent directory. The current selected is opened in the right window.

@section Bufed mode

You can activate it with @kbd{C-x C-b}. You can select with @kbd{RET} or
@kbd{right} the current buffer.

@section XML mode

This mode is currently activated by @kbd{M-x xml-mode}. It is activated
automatically when an XML file is loaded.

Currently, only specific XML colorization is done in this
mode. Javascript (in SCRIPT tags) is colored as in C mode. CSS Style
sheets (in STYLE tags) are colorized with a specific color.

@section Graphical HTML2/CSS mode

@subsection Usage

This mode is currently activated by @kbd{M-x html-mode}. It is
activated automatically when an HTML file is loaded.

@subsection Features

The XML/HTML/CSS2 renderer has the following features:
@itemize
@item The parse errors are written in buffer '*xml-error*'.
@item Strict XML parser or relaxed mode for HTML pages.
@item Letter case can be ignored or strictly respected.
@item Integrated HTML to CSS2 converter so that the renderer do not
     depend on HTML quirks.
@item Quite complete CSS2 support (including generated content and
     counters).
@item Full Bidirectionnal Unicode support.
@item Table support with both 'fixed' and 'auto' layout algorithms.
@item 'tty' and 'screen' CSS2 medias are supported.
@end itemize

@subsection Known limitations

@itemize
@item Cannot load external resources (e.g. style sheets) from other files.
@item No image handling (only a rectangle with 'ALT' name is drawn).
@item No javascript.
@item No frames.
@end itemize

@subsection CSS property support

The following properties are partially (see comments) or totally supported:

@itemize
@item display: The value 'inline-block' is a QEmacs extension.
@item color

@item background-color

@item white-space: The value 'prewrap' is a QEmacs extension.
@item direction

@item float

@item font-family

@item font-style

@item font-weight

@item font-size

@item text-decoration

@item text-align

@item width

@item height

@item unicode-bidi

@item border-width

@item border-left-width

@item border-top-width

@item border-right-width

@item border-bottom-width

@item border-color

@item border-left-color

@item border-top-color

@item border-right-color

@item border-bottom-color

@item border-style

@item border-left-style

@item border-top-style

@item border-right-style

@item border-bottom-style

@item border

@item border-left

@item border-top

@item border-right

@item border-bottom

@item padding

@item padding-left

@item padding-top

@item padding-right

@item padding-bottom

@item margin

@item margin-left

@item margin-top

@item margin-right

@item margin-bottom

@item clear

@item overflow

@item visibility

@item table-layout

@item vertical-align

@item border-collapse

@item border-spacing

@item border-spacing-horizontal

@item border-spacing-vertical

@item line-height

@item content

@item caption-side

@item marker-offset

@item list-style-type

@item column-span: QEmacs extension
@item row-span: QEmacs extension
@item content-alt: QEmacs extension. Same behavior as property 'content' but used for images 

@item list-style-position

@item counter-reset

@item counter-increment

@item bidi-mode: QEmacs extension: use lower/upper case to test bidi algorithm
@item position: @samp{fixed} is not supported. Only 'block' boxes are positionned
@item top

@item bottom

@item left

@item right

@end itemize

The following properties are completely unsupported:

@itemize

@item background

@item background-attachment

@item background-image

@item background-position

@item background-repeat

@item clip

@item cursor

@item empty-cells

@item font

@item font-size-adjust

@item font-stretch

@item font-variant

@item letter-spacing

@item list-style

@item list-style-image

@item max-height

@item max-width

@item min-height

@item min-width

@item outline

@item outline-color

@item outline-style

@item outline-width

@item quotes

@item text-indent

@item text-shadow

@item text-transform

@item word-spacing

@item z-index

@item marks

@item page

@item page-break-after

@item page-break-before

@item page-break-inside

@item size

@item orphans

@item widows

@item azimuth

@item cue

@item cue-after

@item cue-before

@item elevation

@item pause

@item pause-after

@item pause-before

@item pitch

@item pitch-range

@item pitch-during

@item richness

@item speak

@item speak-header

@item speak-punctuation

@item speak-rate

@item stress

@item voice-family

@item volume

@end itemize

@section Graphical DocBook mode

This mode simply uses a different default style sheet from the HTML/CSS2
mode. It is activated by @samp{M-x docbook-mode}.

@section Image mode

When compiling qemacs with FFmpeg support (@url{http://ffmpeg.org}),
images can be viewed. The current implementation handles PNM, PAM, PNG,
JPEG and GIF images (animated GIF images are handled as video
data). @kbd{C-x C-d} can be used to have an interactive file viewer.

Available commands:

@table @kbd
@item t 
(@samp{M-x image-rotate}) Rotate right image by 90 degrees.
@item f
(@samp{M-x toggle-full-screen}) Toggle full screen mode
@item c
(@samp{M-x image-convert}) Change the pixel format of the image (press tab
to have a complete list). The data loss implied by the pixel format
change is displayed.
@item b
(@samp{M-x image-set-background-color}) Set the image background
color. The background is only visible if the image contains transparent
pixels. The @samp{transparent} color displayed a @samp{gimp} like grid.
@end table

Status information: 

@itemize
@item The image resolution is displayed as @samp{NxM}.

@item The FFmpeg pixel format is displayed.

@item @samp{I} is displayed is the image is interleaved.

@item @samp{T} is displayed if the image contains transparent
pixels. @samp{A} is displayed if the image contains semi-transparent
pixels.

@end itemize

@section Audio/Video mode

When compiling qemacs with FFmpeg support (@url{http://ffmpeg.org}),
video and audio files can be viewed. The X11 Xvideo extension is used
if available for faster YUV rendering. @kbd{C-x C-d} can be used to
have an interactive file viewer.

Audio only files are also rendered. The waveform is displayed at the
same time.

No editing commands will be supported in that mode. Saving is
currently not possible.

Available commands:

@table @kbd
@item SPC
@item p
Pause/Resume
@item f
(@samp{M-x toggle-full-screen}) Toggle full screen mode
@item v
(@samp{M-x av-cycle-video}) Cycle through available video channels.
@item a
(@samp{M-x av-cycle-audio}) Cycle through available audio channels.
@end table

@node fonts
@chapter Fonts

@section VT100 display

In order to display Unicode characters, you must have a recent xterm
from XFree version greater than 4.0.1.

As a short test, you can launch xterm with the following options to
select UTF8 charset and a unicode fixed X11 font:
@example
xterm -u8 -fn -misc-fixed-medium-r-normal--18-120-100-100-c-90-iso10646-1
@end example

Then look at the qemacs TestPage in VT100 mode:
@example
qe -nw tests/TestPage.txt
@end example

If you are using latin scripts, you can use any fixed font in any
terminal. Otherwise, if you use ideograms or other non latin scripts,
you must configure your terminal emulator (usually xterm) to accept
'double width' fonts. It means that some characters, such as ideograms,
are meant to occupy two char cells instead of one. QEmacs knows that and
does the text alyout accordingly.

The font @dfn{Unifont} is currently the best font for xterm. It is
usually included in the linux distributions. You can find it at
@url{http://czyborra.com/unifont/}.

@section X11 display

QEmacs knows three basic font families:

@itemize 
@item @samp{sans} for sans serif fonts.
@item @samp{serif} for serif fonts.
@item @samp{fixed} for fixed or monospace fonts.
@end itemize

QEmacs maps these three families to system fonts. The default mapping
is: @samp{helvetica} for sans, @samp{Times} for serif and @samp{fixed}
for fixed.

For each family, you can specify any number of @dfn{fallback fonts} that
QEmacs can use if the requested glyph is not found in the current
font. Currently, the font @samp{unifont} is used as fallback in all
cases.

You can use the command @code{set-system-font(family, fonts)} to change
the default qemacs mapping. @code{family} is @code{sans}, @code{serif}
or @code{fixed}, and @code{fonts} is a comma separated list of system
fonts which are used as principal font and fallback fonts.

@section Internal QEmacs fonts

In the tool @samp{html2png}, QEmacs uses internal fonts which are the
@samp{Times}, @samp{Helvetica} and @samp{Unifont} supplied in X11. They
are highly compressed in the @dfn{FBF} font format.

@chapter Html2png Tool

@section Introduction

Html2png is a standalone HTML/XML/CSS2 renderer based on the QEmacs
internal renderer. It takes an HTML or XHTML file as input and produce a
PNG image file containing the graphical rendering of the page. It is
meant to be a test tool for the renderer. It can also be used as a
XML/HTML validator since all parse errors are logged on the standard
output.

Unlike other HTML renderers, HTML2PNG do not have any dependency on the
operating system or the graphical interface. It uses its own fonts
(which are embedded in the executable), its own widgets and its own
charset tables.

By using the highly compressed FBF font format, the Times, Helvetica and
Unifont fonts are embedded in the executable. It means that HTML2PNG can
view documents in any languages, including Arabic, Hebrew, Japanese and
Hangul.

@section Invocation

@example 
usage: html2png [-h] [-x] [-w width] [-o outfile] [-f charset] infile
@end example

@table @samp
@item -h
display the help
@item -x
use strict XML parser (xhtml type parsing)
@item -w width
set the image width (default=640)
@item -f charset
set the default charset (default='8859-1'). Use -f ? to list supported charsets.
@item -o outfile
set the output filename (default='a.png')
@end table

@chapter Developper's Guide

@section Plugins

You can use the example in @file{plugin-example/} to develop dynamically
linked qemacs plugins (aka modules).

Plugins can add any dynamic resource qemacs supports (modes, key
bindings, ...). A plugin can be either statically linked or
dynamically linked. Most of qemacs features are in fact statically
linked plugins.

@bye