zgv.texi

一个利用SDL语言来实现svgalib函数的示例程序

@kindex Home (Selector)
@item Home
@kindex ^A (Selector)
@itemx ^A
Move the cursor to the start of the list.

@kindex End (Selector)
@item End
@kindex ^E (Selector)
@itemx ^E
Move the cursor to the end of the list.

@kindex g (Selector)
@item g
@kindex ' (Selector)
@itemx '
Move the cursor to the first filename starting with the next key
pressed, which would generally be a letter or number. Case is
significant; @kbd{a} and @kbd{A} are different.

If no files start with the specified character, it moves to the first
file which starts with a later char (in asciibetical order). If there
are none for which this is the case, it moves to the last file ---
unless there are no files (just directories), in which case it has no
effect.

@end table


@node  Viewing a File, Dialog Boxes, Moving Around The List, The File Selector
@comment  node-name,  next,  previous,  up
@section Viewing a File

@cindex viewing a file
@cindex file selector, viewing a file from the
@cindex picture, viewing a

There are two ways to view files from the file selector. The usual way
is to press @kbd{Enter} when you've moved the cursor to the file to
view. However, you can also view tagged files as a `slideshow', which is
described later (@pxref{Tagging}).

@table @kbd
@kindex Enter (Selector)
@item Enter
View a picture file, or if the cursor is on a subdirectory, make that
the current directory. A progress indicator is shown when reading in a
file --- while this is onscreen, you can use @kbd{Esc} to abort.
@end table


@node  Dialog Boxes, Tagging, Viewing a File, The File Selector
@comment  node-name,  next,  previous,  up
@section Dialog Boxes

@cindex dialog boxes
@cindex messages
@cindex errors
@cindex directory dialog

If zgv has a serious problem reading a file, it will give an error.
Errors are shown in boxes which appear in the middle of the screen ---
they stay there until you press @kbd{Enter} or @kbd{Esc} (if using a
mouse, clicking @samp{OK} has the same effect).

zgv also uses similar dialog boxes for other things:

@itemize @minus
@item
Getting a yes or no answer. @kbd{Enter} or @kbd{y} picks `yes';
@kbd{Esc} or @kbd{n} picks no. (Again, you can click on the relevant
button with the mouse to do the same.)

@item
Reading a directory name. Here you should type the directory name then
@kbd{Enter}, or press @kbd{Esc} to abort. In fact, this line-input
dialog allows a certain amount of editing, and so supports these
additional keys:

@table @kbd
@kindex Cursor Left (Dir dialog)
@item Cursor Left
@kindex ^B (Dir dialog)
@itemx ^B
Move the cursor left. (An underline character shows the cursor
position.)

@kindex Cursor Right (Dir dialog)
@item Cursor Right
@kindex ^F (Dir dialog)
@itemx ^F
Move the cursor right.

@kindex Home (Dir dialog)
@item Home
@kindex ^A (Dir dialog)
@itemx ^A
Move the cursor to the start of the line.

@kindex End (Dir dialog)
@item End
@kindex ^E (Dir dialog)
@itemx ^E
Move the cursor to the end of the line.

@kindex Insert (Dir dialog)
@item Insert
@kindex ^I (Dir dialog)
@itemx ^I
Toggle insert/overwrite mode. (Insert mode is the default.) In insert
mode, characters you type are inserted at the cursor position. In
overwrite mode, they replace the existing chars.

@kindex Backspace (Dir dialog)
@item Backspace
@kindex ^H (Dir dialog)
@itemx ^H
Delete char to the left of the cursor. (This assumes @kbd{Backspace}
really generates a @kbd{DEL}, which is the usual setup on Linux. Note
that @kbd{Backspace} is (usually) the key above the main @kbd{Enter}
key; it is often labelled simply as an arrow.)

@kindex Delete (Dir dialog)
@item Delete
@kindex ^D (Dir dialog)
@itemx ^D
Delete the char the cursor is on.
@end table
@end itemize


@node  Tagging, Renaming a File, Dialog Boxes, The File Selector
@comment  node-name,  next,  previous,  up
@section Tagging

@cindex tagging
@cindex marking files
@cindex selecting multiple files

The file selector is not restricted to working on one file at a time.
You can `tag' as many (or as few) files as you wish, and certain
commands described in this section will act on them.

Initially, all files are untagged, and the filenames appear in black.
Tagged files appear in red. (@xref{Configuring zgv}, if you'd prefer zgv
to use different colours.)

@menu
* Tag and Untag Commands::      Selecting multiple files.
* Slideshows::                  How to view them all in turn.
* Copying/Moving/Deleting Files::  Or, do simple file management.
@end menu

@node  Tag and Untag Commands, Slideshows, Tagging, Tagging
@comment  node-name,  next,  previous,  up
@subsection Tag and Untag Commands

@cindex tag and untag commands
@cindex tagging, how to use

There are several ways to tag or untag files. The ones which work on
individual files also move the cursor forward one place afterwards, to
make tagging or untagging multiple files easier.

As elsewhere in zgv, the case of the keys is significant --- the @kbd{t}
(unshifted @kbd{t}) command has quite a different effect to that of
@kbd{T} (shifted @kbd{t}).

There is also a command available in the viewer to tag the
currently-viewed file. @xref{Changing Picture}, for details.

@table @kbd
@kindex t (Selector)
@item t
Tag file.

@kindex n (Selector)
@item n
Untag file. Note that this is @kbd{n} (for `no tag', er, or something
like that); @kbd{u} would be more logical, but that is used for updating
thumbnails.

@kindex T (Selector)
@item T
Tag all files.

@kindex N (Selector)
@item N
Untag all files. This is on @kbd{N} rather than @kbd{U} for consistency.

@kindex Space (Selector)
@item Space
Toggle the tag status of the file --- if it's tagged, untag it; if it's
untagged, tag it.
@end table

To see how many files are tagged, use @kbd{Alt-f} (@pxref{Other File Sel
Commands}).


@node  Slideshows, Copying/Moving/Deleting Files, Tag and Untag Commands, Tagging
@comment  node-name,  next,  previous,  up
@subsection Slideshows

@cindex slideshows
@cindex pictures, slideshow of
@cindex files, slideshow of
@cindex viewing multiple files

A `slideshow' lets you view all the tagged files in the current
directory one after the other, or in a randomised order if `shuffling'
is enabled (@pxref{File Selector Toggles}):

@table @kbd
@kindex Tab (Selector)
@item Tab
View the tagged files as a slideshow. (@kbd{Tab} is usually the key
above @kbd{Caps Lock}, which is often labelled with two arrows.)
@end table

Each file is shown for a certain amount of time, normally 4 seconds.
(@xref{Invoking zgv}, if you find this too short or long.) After the
time runs out, the next file is shown. You can cut this delay short by
hand using one of the viewer's change-picture commands such as
@kbd{Space} (@pxref{Changing Picture}), or abort the slideshow
prematurely by pressing @kbd{Esc}. You can also pause a slideshow so
that you remain on the current file until you unpause it (@pxref{Pausing
Slideshows}).

Normally, once each file has been shown the slideshow ends, and you are
returned to the file selector. But if looping is enabled, the slideshow
repeats until you press @kbd{Esc} (@pxref{File Selector Toggles}).


@node  Copying/Moving/Deleting Files,  , Slideshows, Tagging
@comment  node-name,  next,  previous,  up
@subsection Copying/Moving/Deleting Files

@cindex copying files
@cindex moving files
@cindex files, copying
@cindex files, moving
@cindex pictures, copying
@c one for us Rush fans...
@cindex pictures, moving
@c :-)
@cindex deleting files
@cindex tagged files, deleting
@cindex marked files, deleting

You can copy or move tagged files to a directory you specify, or
delete all tagged files. If no files are tagged, zgv
copies/moves/deletes the file the cursor is currently on --- unless
the cursor is on a subdirectory, in which case it gives an error.

Note that the commands given here are uppercase --- lowercase @kbd{c},
@kbd{m}, and @kbd{d} do not do the same thing.

@table @kbd
@kindex C (Selector)
@item C
Copy tagged files (or the current file) to a given directory. zgv asks
for the destination directory using a dialog (@pxref{Dialog Boxes}) and
copies the files there. If it comes to copy a file but there is an
existing file in the dir with the same name, the file is not copied and
nor are any of the remaining files.

@kindex M (Selector)
@item M
Move tagged files (or the current file) similarly.

@kindex D (Selector)
@item D
Delete tagged files (or the current file) similarly. In this case,
there's obviously no need to specify any directory :-) but you're
prompted before deletion starts (unless this is disabled,
@pxref{Configuring zgv}). It also deletes thumbnails, for those files
which have them.
@end table


@node  Renaming a File, Changing Directory, Tagging, The File Selector
@comment  node-name,  next,  previous,  up
@section Renaming a File

@cindex renaming a file
@cindex file, renaming a
@cindex changing a file's name

As well as copying/moving files, you can rename them:

@table @kbd
@kindex R (Selector)
@item R
@kindex Alt-r (Selector)
@itemx Alt-r
Rename the current file or directory --- zgv will refuse to overwrite
any existing files/directories. The new name must remain in the
current directory. (@xref{Copying/Moving/Deleting Files}, for how to
move a file to a different directory (albeit keeping the same name).)
@end table

It's better to use @kbd{R} than @kbd{Alt-r}; the latter never made much
sense, and is likely to be removed before long.


@node  Changing Directory, Changing the Sorting Order, Renaming a File, The File Selector
@comment  node-name,  next,  previous,  up
@section Changing Directory

@cindex changing directory
@cindex directory, changing
@cindex selecting directory
@cindex current directory
@cindex moving directory
@cindex jumping to a directory

The easiest way to change the current directory in zgv is usually to
select a directory entry in the file list and press @kbd{Enter}.
(Selecting @code{(..)} moves to the parent directory of the current
one.)

There is an alternative though:

(Note that this command is shift-@kbd{g}, not @kbd{g}.)

@table @kbd
@kindex G (Selector)
@item G
Go to a specified directory. zgv asks for the destination directory
using a dialog box which you should type the dir's name into
(@pxref{Dialog Boxes}), and moves to that directory if it exists.

If the directory turns out to be unreadable --- i.e. you do not have
permission to read it --- zgv resorts to going to your home directory.
(This is actually a general mechanism in zgv, but this command is the
most likely trigger of it.) If that in turn is unreadable, zgv gives up
in disgust and exits. :-)
@end table


@node  Changing the Sorting Order, File Selector Toggles, Changing Directory, The File Selector
@comment  node-name,  next,  previous,  up
@section Changing the Sorting Order

@cindex file selector, sorting order of the
@cindex changing the file selector sorting order
@cindex sorting order, changing the file selector's
@cindex size, showing files in order of
@cindex extension, showing files in order of
@cindex date order, showing files in

Normally, the files are listed in asciibetical order by name. However,
you can instead have the file list sorted by size, last-modified
date/time, or by `extension' (the file type).

(Only the order of files can be altered; directories are always listed
first, and always in name order.)

@table @kbd
@kindex Alt-n (Selector)
@item Alt-n
Sort by name. This is the default.

@kindex Alt-s (Selector)
@item Alt-s
Sort by size. The biggest files are listed last.

@kindex Alt-d (Selector)
@item Alt-d