[ViewVC] Contents of: cvs/CV/README

NAME
    cv - a fast gtk+ image viewer loosely modeled after XV

SYNOPSIS
       cv [file...]

FEATURES
    CV is supposed to work similar to the venerable XV image viewer, just
    faster. Why faster?

    * optimized directory scanning algorithm
        The directory scanning in CV uses some tricks that - on most modern
        filesystems - makes it possible to detect filetypes faster than
        stat()'ing every file. This makes CV suitable for directories with
        lots of files (10000+).

        This algorithm is quite unprecise - it doesn't make a difference
        between files, device nodes, symlinks and the like, and filetype
        detection is done using the file extension only.

        On the positive side, it is usually many orders of magnitude faster
        than traditional scanning techniques (good for directories with
        10000 or 100000+ files).

    * queuing for all time-consuming background tasks
        All tasks, such as unlinking files or generating thumbnails, that
        can be done in the background will be done so - no waiting required,
        even when changing directories.

    * use of asynchronous I/O
        CV tries to use asynchronous I/O whereever it makes sense, for
        example while scanning directories, waiting for stat data, unlinking
        files or generating thumbnails. This usually decreases scanning
        times for large directories a bit (especially on RAID devices and
        over NFS) and makes CV much more interactive.

    * fast image loading
        The time span between the user issuing a command and displaying the
        new image should be as small as possible. CV uses optimized
        (especially for JPEG) loading functions and sacrifices some quality
        (e.g no gamma correction, although this might change) to achieve
        this speed.

    * fast thumbnail creation
        Thumbnail creation uses both CPU and Disk-I/O. CV interleaves both,
        so on modern CPUs, thumbnailing is usually limited by I/O speed.
        Thumbnail creation for JPEGs has been specially optimized and can
        even take advantage of multiple CPUs.

    * minimum optical clutter
        CV has no menus or other user interface elements that take up a lot
        of screen space (or are useful for beginning users). The schnauzer
        windows can also be somewhat crowded.

        The point of an image viewer is viewing images, not a nice GUI. This
        is similar to XV's behaviour.

    * efficient (and hard to learn) user interface
        CV uses key combinations. A lot. If you are an experienced XV user,
        you will find most of these keys familiar. If not, CV might be hard
        to use at first, but will be an efficient tool later.

    * multi-window GUI
        CV doesn't force you to use a specific layout, instead it relies on
        your window manager, thus enabling you to chose whatever layout that
        suits you most.

    * i18n'ed filename handling throughout
        As long as glib can recognize your filename encoding (either UTF-8
        or locale-specific, depending on the setting of G_BROKEN_FILENAMES)
        and you have the relevant fonts, CV will display your filenames
        correctly.

    * extensible through plug-ins
        I have weird plug-ins that access remote databases to find a
        directory. This is not likely to be of any use to other people.
        Likewise, others might have weird requirements I cannot dream of.

    * filename clustering
        Among the standard plug-ins is a filename clustering plug-in, that
        (in case of tens of thousands images in one directory) might be able
        to cluster similar names together.

DESCRIPTION
  THE IMAGE WINDOW
    You can use the following keys in the image window:

     q            quit the program
     <            half the image size
     >            double the image size
     ,            shrink the image by 10%
     .            enlarge the image by 10%
     n            reset to normal size
     m            maximize to screensize
     M            maximize to screensize, respecting image aspect
     ctrl-m       toggle maxpect-always mode
     ctrl-sift-m  toggle using current image size as max image size
     u            uncrop
     r            set scaling mode to 'nearest' (fastest)
     s            set scaling mode to 'bilinear' (default)
     shift-s      set scaling mode to 'hyper' (slowest)
     t            rotate clockwise 90°
     T            rotate counterclockwise°
     a            apply all rotations loslessly to a jpeg file (using exiftran)
     ctrl-v       open a new visual schnauzer window for the current dir
     ctrl-c       clone the current image window
     ctrl-e       run an editor ($CV_EDITOR or "gimp") on the current image
     ctrl-p       fire up the print dialog
     escape       cancel a crop action

    And when playing movies, these additional keys are active:

     left         rewind by 10 seconds
     right        forward by 10 seconds
     down         rewind by 60 seconds
     up           forward by 60 seconds
     pg_up        rewind by 600 seconds
     pg_down      forward by 600 seconds
     o            toggle on-screen display
     p            pause/unpause
     escape       stop playing
     9            turn volume down
     0            turn volume up

    Any other keys will be sent to the default schnauzer window, which can
    be toggled on and off by right-clicking into the image window.

    Left-clicking into the image window will let you crop the image (usually
    to zoom into large images that CV scales down).

  THE VISUAL SCHNAUZER
    Any image-loading action in a schnauzer window acts on the
    "last-recently-activated" imagewindow, which currently is simply the
    last image window that received a keypress.

    You can use the following keys in the schnauzer window:

     ctrl-space,
     space        move to and display next image
     ctrl-backspace,
     backspace    move to and display previous image
     ctrl-return,
     return       display selected picture, or enter directory

     cursor keys  move selection
     page-up      move one page up
     page-down    move one page down
     home         move to first file
     end          move to last file

     ctrl-a       select all files
     ctrl-shift-a select all files currently displayed in the schnauzer window
     ctrl-d       delete selected files WITHOUT ASKING AGAIN
     ctrl-g       force generation of thumbnais for the selected files
     ctrl-s       rescan current direcory or files updates/deletes etc.
     ctrl-u       update selected (or all) icons if neccessary
     ctrl-l       don't use, will become a plug-in eventually

     ^            go to parent directory (caret).

     0-9,
     a-z          find the first filename beginning with this letter

    Right-clicking into the schnauzer window displays a pop-up menu with
    additional actions.

   SELECTION
    You can select entries in the Schnauzer in a variety of ways:

    Keyboard
        Moving the cursor with the keyboard will first deselect all files
        and then select the file you moved to.

    Clicking
        Clicking on an entry will select the one you clicked and deselect
        all others.

    Shift-Clicking
        Shift-clicking will toggle the selection on the entry under the
        mouse.

    Dragging
        Dragging will select all entries between the one selected when
        pushing the button and the one selected when releasing the button.
        If you move above or below the schnauzer area while drag-selecting,
        the schnauzer will move up/down one row twice per second. In
        addition, horizontal mouse movement acts as a kind of invisible
        horizontal scrollbar.

    Hint: double-click works while click-selecting
        You can double-click any image while click-selecting to display it
        without stopping the selection process. This will act as if you
        normally double-clicked the image to display it, and will toggle the
        selection twice, resulting in no change.

FILES
    When starting, CV runs the .cvrc file in your $HOME directory as if it
    were a perl script. in that, you will mostly load plug-ins.

    Example:

       system "fping -q -t 10 ether"
         or require "/fs/cv/cvplugin.pl";

    This will load a plug-in, but only if the machine *ether* is reachable
    (supposedly the plug-in is networked in some way :).

ENVIRONMENT
    CV_EDITOR
        The program that gets executed when the user presses "CTRL-e" in the
        Schnauzer or image window. The default is "gimp".

    CV_AUDIO_PLAYER
        Program used to play all sorts of audio (wav, aif, mp3, ogg...),
        default "play". Will be called like "$CV_AUDIO_PLAYER -- <path>".

    CV_PRINT_DESTINATION
        The default (perl-style) destination to use in the print dialog.

    CV_TRASHCAN
        When set, must point to a directory where all files that are deleted
        are moved to. If unset, files that are deleted are really being
        deleted.

SECURITY CONSIDERATIONS
    CV uses Pixbuf to load non-JPEG images. Pixbuf is not considered safe
    for this purpose, though (from the gtk-2.2 release notes):

    "While efforts have been made to make gdk-pixbuf robust against invalid
    images, using gdk-pixbuf to load untrusted data is not recommended, due
    to the likelyhood that there are additional problems where an invalid
    image could cause gdk-pixbuf to crash or worse."

BUGS/TODO
     Lots of functionality is missing.

     Pixbuf doesn't always honor G_BROKEN_FILENAMES, so accessing files with
     names incompatible with utf-8 might fail.

     rotate on disk
     lots of ui issues
     save(?)
     preferences

AUTHOR
    Marc Lehmann <cv@plan9.de>.

Revision:	1.6
Committed:	Sun Nov 25 14:16:35 2007 UTC (16 years, 5 months ago) by root
Branch:	MAIN
CVS Tags:	rel-1_5
Changes since 1.5:	+4 -0 lines
Log Message:	* empty log message *
#	Content
1	NAME
2	cv - a fast gtk+ image viewer loosely modeled after XV
3
4	SYNOPSIS
5	cv [file...]
6
7	FEATURES
8	CV is supposed to work similar to the venerable XV image viewer, just
9	faster. Why faster?
10
11	* optimized directory scanning algorithm
12	The directory scanning in CV uses some tricks that - on most modern
13	filesystems - makes it possible to detect filetypes faster than
14	stat()'ing every file. This makes CV suitable for directories with
15	lots of files (10000+).
16
17	This algorithm is quite unprecise - it doesn't make a difference
18	between files, device nodes, symlinks and the like, and filetype
19	detection is done using the file extension only.
20
21	On the positive side, it is usually many orders of magnitude faster
22	than traditional scanning techniques (good for directories with
23	10000 or 100000+ files).
24
25	* queuing for all time-consuming background tasks
26	All tasks, such as unlinking files or generating thumbnails, that
27	can be done in the background will be done so - no waiting required,
28	even when changing directories.
29
30	* use of asynchronous I/O
31	CV tries to use asynchronous I/O whereever it makes sense, for
32	example while scanning directories, waiting for stat data, unlinking
33	files or generating thumbnails. This usually decreases scanning
34	times for large directories a bit (especially on RAID devices and
35	over NFS) and makes CV much more interactive.
36
37	* fast image loading
38	The time span between the user issuing a command and displaying the
39	new image should be as small as possible. CV uses optimized
40	(especially for JPEG) loading functions and sacrifices some quality
41	(e.g no gamma correction, although this might change) to achieve
42	this speed.
43
44	* fast thumbnail creation
45	Thumbnail creation uses both CPU and Disk-I/O. CV interleaves both,
46	so on modern CPUs, thumbnailing is usually limited by I/O speed.
47	Thumbnail creation for JPEGs has been specially optimized and can
48	even take advantage of multiple CPUs.
49
50	* minimum optical clutter
51	CV has no menus or other user interface elements that take up a lot
52	of screen space (or are useful for beginning users). The schnauzer
53	windows can also be somewhat crowded.
54
55	The point of an image viewer is viewing images, not a nice GUI. This
56	is similar to XV's behaviour.
57
58	* efficient (and hard to learn) user interface
59	CV uses key combinations. A lot. If you are an experienced XV user,
60	you will find most of these keys familiar. If not, CV might be hard
61	to use at first, but will be an efficient tool later.
62
63	* multi-window GUI
64	CV doesn't force you to use a specific layout, instead it relies on
65	your window manager, thus enabling you to chose whatever layout that
66	suits you most.
67
68	* i18n'ed filename handling throughout
69	As long as glib can recognize your filename encoding (either UTF-8
70	or locale-specific, depending on the setting of G_BROKEN_FILENAMES)
71	and you have the relevant fonts, CV will display your filenames
72	correctly.
73
74	* extensible through plug-ins
75	I have weird plug-ins that access remote databases to find a
76	directory. This is not likely to be of any use to other people.
77	Likewise, others might have weird requirements I cannot dream of.
78
79	* filename clustering
80	Among the standard plug-ins is a filename clustering plug-in, that
81	(in case of tens of thousands images in one directory) might be able
82	to cluster similar names together.
83
84	DESCRIPTION
85	THE IMAGE WINDOW
86	You can use the following keys in the image window:
87
88	q quit the program
89	< half the image size
90	> double the image size
91	, shrink the image by 10%
92	. enlarge the image by 10%
93	n reset to normal size
94	m maximize to screensize
95	M maximize to screensize, respecting image aspect
96	ctrl-m toggle maxpect-always mode
97	ctrl-sift-m toggle using current image size as max image size
98	u uncrop
99	r set scaling mode to 'nearest' (fastest)
100	s set scaling mode to 'bilinear' (default)
101	shift-s set scaling mode to 'hyper' (slowest)
102	t rotate clockwise 90°
103	T rotate counterclockwise°
104	a apply all rotations loslessly to a jpeg file (using exiftran)
105	ctrl-v open a new visual schnauzer window for the current dir
106	ctrl-c clone the current image window
107	ctrl-e run an editor ($CV_EDITOR or "gimp") on the current image
108	ctrl-p fire up the print dialog
109	escape cancel a crop action
110
111	And when playing movies, these additional keys are active:
112
113	left rewind by 10 seconds
114	right forward by 10 seconds
115	down rewind by 60 seconds
116	up forward by 60 seconds
117	pg_up rewind by 600 seconds
118	pg_down forward by 600 seconds
119	o toggle on-screen display
120	p pause/unpause
121	escape stop playing
122	9 turn volume down
123	0 turn volume up
124
125	Any other keys will be sent to the default schnauzer window, which can
126	be toggled on and off by right-clicking into the image window.
127
128	Left-clicking into the image window will let you crop the image (usually
129	to zoom into large images that CV scales down).
130
131	THE VISUAL SCHNAUZER
132	Any image-loading action in a schnauzer window acts on the
133	"last-recently-activated" imagewindow, which currently is simply the
134	last image window that received a keypress.
135
136	You can use the following keys in the schnauzer window:
137
138	ctrl-space,
139	space move to and display next image
140	ctrl-backspace,
141	backspace move to and display previous image
142	ctrl-return,
143	return display selected picture, or enter directory
144
145	cursor keys move selection
146	page-up move one page up
147	page-down move one page down
148	home move to first file
149	end move to last file
150
151	ctrl-a select all files
152	ctrl-shift-a select all files currently displayed in the schnauzer window
153	ctrl-d delete selected files WITHOUT ASKING AGAIN
154	ctrl-g force generation of thumbnais for the selected files
155	ctrl-s rescan current direcory or files updates/deletes etc.
156	ctrl-u update selected (or all) icons if neccessary
157	ctrl-l don't use, will become a plug-in eventually
158
159	^ go to parent directory (caret).
160
161	0-9,
162	a-z find the first filename beginning with this letter
163
164	Right-clicking into the schnauzer window displays a pop-up menu with
165	additional actions.
166
167	SELECTION
168	You can select entries in the Schnauzer in a variety of ways:
169
170	Keyboard
171	Moving the cursor with the keyboard will first deselect all files
172	and then select the file you moved to.
173
174	Clicking
175	Clicking on an entry will select the one you clicked and deselect
176	all others.
177
178	Shift-Clicking
179	Shift-clicking will toggle the selection on the entry under the
180	mouse.
181
182	Dragging
183	Dragging will select all entries between the one selected when
184	pushing the button and the one selected when releasing the button.
185	If you move above or below the schnauzer area while drag-selecting,
186	the schnauzer will move up/down one row twice per second. In
187	addition, horizontal mouse movement acts as a kind of invisible
188	horizontal scrollbar.
189
190	Hint: double-click works while click-selecting
191	You can double-click any image while click-selecting to display it
192	without stopping the selection process. This will act as if you
193	normally double-clicked the image to display it, and will toggle the
194	selection twice, resulting in no change.
195
196	FILES
197	When starting, CV runs the .cvrc file in your $HOME directory as if it
198	were a perl script. in that, you will mostly load plug-ins.
199
200	Example:
201
202	system "fping -q -t 10 ether"
203	or require "/fs/cv/cvplugin.pl";
204
205	This will load a plug-in, but only if the machine ether is reachable
206	(supposedly the plug-in is networked in some way :).
207
208	ENVIRONMENT
209	CV_EDITOR
210	The program that gets executed when the user presses "CTRL-e" in the
211	Schnauzer or image window. The default is "gimp".
212
213	CV_AUDIO_PLAYER
214	Program used to play all sorts of audio (wav, aif, mp3, ogg...),
215	default "play". Will be called like "$CV_AUDIO_PLAYER -- <path>".
216
217	CV_PRINT_DESTINATION
218	The default (perl-style) destination to use in the print dialog.
219
220	CV_TRASHCAN
221	When set, must point to a directory where all files that are deleted
222	are moved to. If unset, files that are deleted are really being
223	deleted.
224
225	SECURITY CONSIDERATIONS
226	CV uses Pixbuf to load non-JPEG images. Pixbuf is not considered safe
227	for this purpose, though (from the gtk-2.2 release notes):
228
229	"While efforts have been made to make gdk-pixbuf robust against invalid
230	images, using gdk-pixbuf to load untrusted data is not recommended, due
231	to the likelyhood that there are additional problems where an invalid
232	image could cause gdk-pixbuf to crash or worse."
233
234	BUGS/TODO
235	Lots of functionality is missing.
236
237	Pixbuf doesn't always honor G_BROKEN_FILENAMES, so accessing files with
238	names incompatible with utf-8 might fail.
239
240	rotate on disk
241	lots of ui issues
242	save(?)
243	preferences
244
245	AUTHOR
246	Marc Lehmann <cv@plan9.de>.
247