various: define builtin options and key bindings for images

This makes mpv a good image viewer out of the box, as it is currently
hard to setup.

It adds a builtin image conditional profile that users can extend in
mpv.conf. It is written to not restore and reapply the options on each
image change, because that is slow for certain options (e.g.
--d3d11-flip=no restarts the VO), and causes visible flicker when
options like gamma are unapplied before changing image and reapplied on
the next image. But it still restores the previous options after
switching to a video or audio file.

etc/image-input.conf defines default key bindings for image, and
~/.config/mpv/image-input.conf can override them. sxiv is the main
inspiration for the default key bindings.

Files called image-input.conf are added to an input section called
image, and builtin.conf enables it for images and disables it for
non-images. Because enable-section and disable-section are only called
in builtin.conf, they can be replaced with a different mechanism when
deprecated input sections are removed without a breaking change.

DOCS/man/input.rst

@@ -25,6 +25,12 @@ defined here::
 
     https://github.com/mpv-player/mpv/blob/master/etc/input.conf
 
+Additionally, ``image-input.conf`` can be placed in mpv's configuration
+directory to enable key bindings exclusively for images. The default image
+bindings are defined here::
+
+    https://github.com/mpv-player/mpv/blob/master/etc/image-input.conf
+
 A list of special keys can be obtained with
 
     ``mpv --input-keylist``

DOCS/man/mpv.rst

@@ -371,6 +371,79 @@ To use this feature, you need to fill the ``menu-data`` property with menu
 definition data, and add a keybinding to run the ``context-menu`` command,
 which can be done with a user script.
 
+Image Bindings
+--------------
+
+Several key bindings are changed when viewing images:
+
+LEFT, RIGHT, UP, DOWN, h, j, k, l
+    Pan the image when it is larger than the window.
+
+Ctrl+LEFT, Ctrl+RIGHT, Ctrl+UP, Ctrl+DOWN, Ctrl+h, Ctrl+j, Ctrl+k, Ctrl+l
+    Align the image to one of the boundaries of the window when it is larger
+    than the window.
+
+= and -
+    Change the zoom.
+
++ and _
+    Change the zoom slowly.
+
+0
+    Reset the zoom.
+
+u
+    Toggle between showing the image unscaled in its original dimensions and
+    fitting it to the window.
+
+o
+    Fill the window with the image.
+
+s
+    Toggle between showing images for 5 seconds in a slideshow and keeping them
+    open forever.
+
+n
+    Go to the next playlist entry.
+
+p
+    Go to the previous playlist entry.
+
+N
+    Go to the next sub-playlist (e.g. directory or achive).
+
+P
+    Go to the previous sub-playlist.
+
+g-g
+    Go to the first playlist entry.
+
+G
+    Go to the last playlist entry.
+
+]
+    Skip 10 playlist entries forwards.
+
+[
+    Skip 10 playlist entries backwards.
+
+r and R
+    Rotate counterclockwise.
+
+t
+    Rotate clockwise.
+
+v
+    Rotate by 180 degrees.
+
+Right click
+    Pan while holding the button keeping the clicked part of the image under the
+    cursor.
+
+Wheel up/down
+    Change the zoom while keeping the part of the image hovered by the cursor
+    under it.
+
 USAGE
 =====
 
@@ -1008,6 +1081,40 @@ example, ``math`` is defined and gives access to the Lua standard math library.
     This feature is subject to change indefinitely. You might be forced to
     adjust your profiles on mpv updates.
 
+Image profile
+-------------------
+
+mpv has a builtin conditional profile that is automatically applied to images
+and restored when switching to a video or audio file. Its options are:
+
+.. admonition:: Builtin profile definition
+
+    ::
+
+        [image]
+        osc=no
+        prefetch-playlist
+        input-preprocess-wheel=no
+
+It can be extended in mpv.conf without overwriting it completely:
+
+.. admonition:: Example to enable the screensaver with images
+
+    ::
+
+        [image]
+        stop-screensaver=no
+
+This profile uses ``--input-commands`` to enable image specific key bindings.
+This can be disabled with ``input-commands-clr``. Extra commands should be
+specified with ``input-commands-append`` to keep enabling the image key
+bindings.
+
+To reset zoom and rotation between images, it is recommended to place
+``reset-on-next-file=video-rotate,video-zoom,panscan,video-unscaled`` in the top
+level of mpv.conf, as enabling it a conditional profile makes it take effect
+only from the second file.
+
 Legacy auto profiles
 --------------------
 
@@ -1653,6 +1760,9 @@ All configuration files should be encoded in UTF-8.
 ``~/.config/mpv/input.conf``
     key bindings (see `INPUT.CONF`_ section)
 
+``~/.config/mpv/image-input.conf``
+    key bindings for images (see `INPUT.CONF`_ section)
+
 ``~/.config/mpv/fonts.conf``
     Fontconfig fonts.conf that is customized for mpv. You should include system
     fonts.conf in this file or mpv would not know about fonts that you already

etc/builtin.conf

@@ -97,3 +97,15 @@ sub-shadow-offset=4
 [box]
 profile=osd-box
 profile=sub-box
+
+[image]
+profile-cond=(get('current-tracks/video', {}).image and not get('current-tracks/video', {}).albumart) or (not get('current-tracks/video') and get('user-data/mpv/image'))
+profile-restore=copy
+input-commands=no-osd set user-data/mpv/image 1; enable-section image allow-hide-cursor+allow-vo-dragging
+osc=no
+prefetch-playlist
+input-preprocess-wheel=no
+
+[non-image]
+profile-cond=get('user-data/mpv/image') and (not get('current-tracks/video', {}).image or get('current-tracks/video', {}).albumart)
+input-commands=no-osd del user-data/mpv/image; disable-section image

etc/image-input.conf

@@ -0,0 +1,86 @@
+# Image key bindings
+#
+# Location of user-defined bindings: ~/.config/mpv/image-input.conf
+#
+# Lines starting with # are comments. Use SHARP to assign the # key.
+# Copy this file and uncomment and edit the bindings you want to change.
+#
+# List of commands and further details: DOCS/man/input.rst
+# List of special keys: --input-keylist
+# Keybindings testing mode: mpv --input-test --force-window --idle
+#
+# Use 'ignore' to unbind a key fully (e.g. 'ctrl+a ignore').
+#
+# Strings need to be quoted and escaped:
+#   KEY show-text "This is a single backslash: \\ and a quote: \" !"
+#
+# You can use modifier-key combinations like Shift+Left or Ctrl+Alt+x with
+# the modifiers Shift, Ctrl, Alt and Meta (may not work on the terminal).
+#
+# The default keybindings are hardcoded into the mpv binary.
+# You can disable them completely with: --no-input-default-bindings
+
+#LEFT        script-binding/positioning pan-x -0.2 # pan left
+#DOWN        script-binding/positioning pan-y  0.2 # pan down
+#UP          script-binding/positioning pan-y -0.2 # pan up
+#RIGHT       script-binding/positioning pan-x  0.2 # pan right
+#h           script-binding/positioning pan-x -0.2 # pan left
+#j           script-binding/positioning pan-y  0.2 # pan down
+#k           script-binding/positioning pan-y -0.2 # pan up
+#l           script-binding/positioning pan-x  0.2 # pan right
+#Shift+LEFT  script-binding/positioning pan-x -0.02 # pan left slowly
+#Shift+DOWN  script-binding/positioning pan-y  0.02 # pan down slowly
+#Shift+UP    script-binding/positioning pan-y -0.02 # pan up slowly
+#Shift+RIGHT script-binding/positioning pan-x  0.02 # pan right slowly
+#H           script-binding/positioning pan-x -0.02 # pan left slowly
+#J           script-binding/positioning pan-y  0.02 # pan down slowly
+#K           script-binding/positioning pan-y -0.02 # pan up slowly
+#L           script-binding/positioning pan-x  0.02 # pan right slowly
+
+# Recommened on a touchpad:
+# WHEEL_UP    script-binding/positioning pan-y -0.2 # pan up
+# WHEEL_DOWN  script-binding/positioning pan-y  0.2 # pan down
+# WHEEL_LEFT  script-binding/positioning pan-x -0.2 # pan left
+# WHEEL_RIGHT script-binding/positioning pan-x  0.2 # pan right
+
+#Ctrl+LEFT   no-osd set video-align-x -1 # align to the left
+#Ctrl+DOWN   no-osd set video-align-y  1 # align to the bottom
+#Ctrl+UP     no-osd set video-align-y -1 # align to the top
+#Ctrl+RIGHT  no-osd set video-align-x  1 # align to the right
+#Ctrl+h      no-osd set video-align-x -1 # align to the left
+#Ctrl+j      no-osd set video-align-y  1 # align to the bottom
+#Ctrl+k      no-osd set video-align-y -1 # align to the top
+#Ctrl+l      no-osd set video-align-x  1 # align to the right
+
+= add video-zoom  0.25 # zoom in
+- add video-zoom -0.25 # zoom out
++ add video-zoom  0.05 # zoom in slowly
+_ add video-zoom -0.05 # zoom out slowly
+0 no-osd set video-zoom 0; no-osd set panscan 0 # reset zoom
+
+#u no-osd cycle-values video-unscaled yes no; no-osd set video-zoom 0; no-osd set panscan 0 # toggle scaling the image to the window.
+
+#o no-osd set panscan 1; no-osd set video-unscaled no; no-osd set video-zoom 0 # fill black bars
+
+#MBTN_RIGHT script-binding positioning/drag-to-pan # pan around the clicked point
+
+#WHEEL_UP   script-message cursor-centric-zoom  0.1 # zoom in towards the cursor
+#WHEEL_DOWN script-message cursor-centric-zoom -0.1 # zoom out towards the cursor
+
+#s cycle-values image-display-duration 5 inf; no-osd set video-zoom 0; no-osd set panscan 0; no-osd set video-unscaled no # toggle slideshow
+
+#n repeatable playlist-next # go to the next file
+#p repeatable playlist-prev # go to the previous file
+#N playlist-next-playlist   # go to the next sub-playlist
+#P playlist-prev-playlist   # go to the previous sub-playlist
+
+#g-g no-osd set playlist-pos 0                 # go to the first playlist entry
+#G no-osd set playlist-pos-1 ${playlist-count} # go to the last playlist entry
+
+] no-osd add playlist-pos 10  # go 10 playlist entries forwards
+[ no-osd add playlist-pos -10 # go 10 playlist entries backwards
+
+#r cycle-values video-rotate 270 180 90 0 # rotate counterclockwise
+#R cycle-values video-rotate 270 180 90 0 # rotate counterclockwise
+#t cycle-values video-rotate 90 180 270 0 # rotate clockwise
+#v cycle-values video-rotate 0 180        # rotate by 180 degrees

etc/meson.build

@@ -9,7 +9,7 @@ foreach size: icons
     sources += icon
 endforeach
 
-etc_files = ['input.conf', 'builtin.conf']
+etc_files = ['input.conf', 'builtin.conf', 'image-input.conf']
 foreach file: etc_files
     etc_file = custom_target(file,
         input: file,

input/input.c

@@ -249,6 +249,10 @@ static const char builtin_input_conf[] =
 #include "etc/input.conf.inc"
 ;
 
+static const char builtin_image_input_conf[] =
+#include "etc/image-input.conf.inc"
+;
+
 static bool test_rect(struct mp_rect *rc, int x, int y)
 {
     return x >= rc->x0 && y >= rc->y0 && x < rc->x1 && y < rc->y1;
@@ -1477,9 +1481,13 @@ static bool parse_config_file(struct input_ctx *ictx, char *file)
     bstr data = stream_read_file2(file, tmp, STREAM_ORIGIN_DIRECT | STREAM_READ,
                                   ictx->global, 1000000);
     if (data.start) {
+        bstr section = (bstr){0};
+        if (!strcmp(mp_basename(file), "image-input.conf"))
+            section = bstr0("image");
+
         MP_VERBOSE(ictx, "Parsing input config file %s\n", file);
         bstr_eatstart0(&data, "\xEF\xBB\xBF"); // skip BOM
-        int num = parse_config(ictx, false, data, file, (bstr){0});
+        int num = parse_config(ictx, false, data, file, section);
         MP_VERBOSE(ictx, "Input config file %s parsed: %d binds\n", file, num);
         r = true;
     } else {
@@ -1560,13 +1568,24 @@ void mp_input_load_config(struct input_ctx *ictx)
             parse_config(ictx, true, line, "<builtin>", (bstr){0});
     }
 
+    builtin = bstr0(builtin_image_input_conf);
+    while (ictx->opts->builtin_bindings && builtin.len) {
+        bstr line = bstr_getline(builtin, &builtin);
+        bstr_eatstart0(&line, "#");
+        if (!bstr_startswith0(line, " "))
+            parse_config(ictx, true, line, "<builtin-image>", bstr0("image"));
+    }
+
     bool config_ok = false;
     if (ictx->opts->config_file && ictx->opts->config_file[0])
         config_ok = parse_config_file(ictx, ictx->opts->config_file);
     if (!config_ok) {
         // Try global conf dir
         void *tmp = talloc_new(NULL);
         char **files = mp_find_all_config_files(tmp, ictx->global, "input.conf");
+        for (int n = 0; files && files[n]; n++)
+            parse_config_file(ictx, files[n]);
+        files = mp_find_all_config_files(tmp, ictx->global, "image-input.conf");
         for (int n = 0; files && files[n]; n++)
             parse_config_file(ictx, files[n]);
         talloc_free(tmp);

meson.build

@@ -1787,7 +1787,7 @@ if get_option('cplayer')
     datadir = get_option('datadir')
     confdir = get_option('sysconfdir')
 
-    conf_files = ['etc/mpv.conf', 'etc/input.conf',
+    conf_files = ['etc/mpv.conf', 'etc/input.conf', 'etc/image-input.conf',
                   'etc/mplayer-input.conf', 'etc/restore-old-bindings.conf',
                   'etc/restore-osc-bindings.conf']
     install_data(conf_files, install_dir: join_paths(datadir, 'doc', 'mpv'))