feat: add output listing capability (#317)

* feat: add output listing capability

* Add help command and man entry for --list-output

* fix typo

* Extract print available outputs code into function for reusability

* fix typo in manpage

Author: nabiko02

README.md

@@ -92,6 +92,7 @@ The man page can be read with `man ./manpage/wf-recorder.1`.
 In its simplest form, run `wf-recorder` to start recording and use Ctrl+C to stop. This will create a file called `recording.mp4` in the current working directory using the default codec.
 
 Use `-f <filename>` to specify the output file. In case of multiple outputs, you'll first be prompted to select the output you want to record. If you know the output name beforehand, you can use the `-o <output name>` option.
+To view all available output options, use the list flag `-L` or `--list-output`
 
 To select a specific part of the screen you can either use `-g <geometry>`, or use [slurp](https://github.com/emersion/slurp) for interactive selection of the screen area that will be recorded:
 

manpage/wf-recorder.1

@@ -21,6 +21,7 @@
 .Op Fl h, -help
 .Op Fl l, -log
 .Op Fl m, -muxer Ar muxer
+.Op Fl L, -list-output
 .Op Fl o, -output Ar output
 .Op Fl p, -codec-param Op Ar option_param=option_value
 .Op Fl v, -version
@@ -133,6 +134,9 @@ Generates a log on the current terminal. For debug purposes.
 .It Fl m , -muxer Ar muxer
 Set the output format to a specific muxer instead of detecting it from the filename.
 .Pp
+.It Fl L , -list-output
+List the available outputs.
+.Pp
 .It Fl o , -output
 Specify the output where the video is to be recorded.
 .Pp

src/main.cpp

@@ -805,16 +805,23 @@ static void load_output_info()
     sync_wayland();
 }
 
-static wf_recorder_output* choose_interactive()
+static void print_available_outputs()
 {
-    fprintf(stdout, "Please select an output from the list to capture (enter output no.):\n");
-
     int i = 1;
     for (auto& wo : available_outputs)
     {
         printf("%d. Name: %s Description: %s\n", i++, wo.name.c_str(),
             wo.description.c_str());
     }
+}
+
+
+
+static wf_recorder_output* choose_interactive()
+{
+    fprintf(stdout, "Please select an output from the list to capture (enter output no.):\n");
+
+    print_available_outputs();
 
     printf("Enter output no.:");
     fflush(stdout);
@@ -942,6 +949,8 @@ Use Ctrl+C to stop.)");
 
   -l, --log                 Generates a log on the current terminal. Debug purposes.
 
+  -L, --list-output          List the available outputs.
+  
   -o, --output              Specify the output where the video is to be recorded.
 
   -p, --codec-param         Change the codec parameters.
@@ -1050,6 +1059,29 @@ static void parse_codec_opts(std::map<std::string, std::string>& options, const
     }
 }
 
+static void init_wayland_client()
+{
+    display = wl_display_connect(NULL);
+    if (display == NULL)
+    {
+        fprintf(stderr, "failed to create display: %m\n");
+        exit(EXIT_FAILURE);
+    }
+    struct wl_registry *registry = wl_display_get_registry(display);
+    wl_registry_add_listener(registry, &registry_listener, NULL);
+    sync_wayland();
+}
+
+static void list_available_outputs()
+{
+    init_wayland_client();
+    load_output_info();
+    print_available_outputs();
+
+    exit(EXIT_SUCCESS);
+}
+
+
 int main(int argc, char *argv[])
 {
     FrameWriterParams params = FrameWriterParams(exit_main_loop);
@@ -1092,11 +1124,12 @@ int main(int argc, char *argv[])
         { "version",           no_argument,       NULL, 'v' },
         { "no-damage",         no_argument,       NULL, 'D' },
         { "overwrite",         no_argument,       NULL, 'y' },
+        { "list-output",       no_argument,       NULL, 'L' },
         { 0,                   0,                 NULL,  0  }
     };
 
     int c, i;
-    while((c = getopt_long(argc, argv, "o:f:m:g:c:p:r:x:C:P:R:X:d:b:B:la::hvDF:y", opts, &i)) != -1)
+    while((c = getopt_long(argc, argv, "o:f:m:g:c:p:r:x:C:P:R:X:d:b:B:la::hvDF:y:L", opts, &i)) != -1)
     {
         switch(c)
         {
@@ -1197,6 +1230,10 @@ int main(int argc, char *argv[])
             case 'y':
                 force_overwrite = true;
                 break;
+
+            case 'L':
+                list_available_outputs();
+                break;
 #ifdef HAVE_AUDIO
             case '*':
                 audioParams.audio_backend = optarg;
@@ -1212,16 +1249,7 @@ int main(int argc, char *argv[])
         return EXIT_FAILURE;
     }
 
-    display = wl_display_connect(NULL);
-    if (display == NULL)
-    {
-        fprintf(stderr, "failed to create display: %m\n");
-        return EXIT_FAILURE;
-    }
-
-    struct wl_registry *registry = wl_display_get_registry(display);
-    wl_registry_add_listener(registry, &registry_listener, NULL);
-    sync_wayland();
+    init_wayland_client();
 
     if (params.codec.find("vaapi") != std::string::npos)
     {