Add --list-displays

Add an option to list the device displays properly.

README.md

@@ -718,7 +718,7 @@ scrcpy --display=1
 The list of display ids can be retrieved by:
 
 ```bash
-adb shell dumpsys display   # search "mDisplayId=" in the output
+scrcpy --list-displays
 ```
 
 The secondary display may only be controlled if the device runs at least Android

app/data/bash-completion/scrcpy

@@ -19,6 +19,7 @@ _scrcpy() {
         -K --hid-keyboard
         -h --help
         --legacy-paste
+        --list-displays
         --list-encoders
         --lock-video-orientation
         --lock-video-orientation=

app/data/zsh-completion/_scrcpy

@@ -26,6 +26,7 @@ arguments=(
     {-K,--hid-keyboard}'[Simulate a physical keyboard by using HID over AOAv2]'
     {-h,--help}'[Print the help]'
     '--legacy-paste[Inject computer clipboard text as a sequence of key events on Ctrl+v]'
+    '--list-displays[List displays available on the device]'
     '--list-encoders[List video and audio encoders available on the device]'
     '--lock-video-orientation=[Lock video orientation]:orientation:(unlocked initial 0 1 2 3)'
     '--max-fps=[Limit the frame rate of screen capture]'

app/scrcpy.1

@@ -73,10 +73,9 @@ Disable screensaver while scrcpy is running.
 
 .TP
 .BI "\-\-display " id
-Specify the display id to mirror.
+Specify the device display id to mirror.
 
-The list of possible display ids can be listed by "adb shell dumpsys display"
+The available display ids can be listed by \-\-list\-displays.
-(search "mDisplayId=" in the output).
 
 Default is 0.
 
@@ -134,6 +133,10 @@ This is a workaround for some devices not behaving as expected when setting the
 .B \-\-list\-encoders
 List video and audio encoders available on the device.
 
+.TP
+.B \-\-list\-displays
+List displays available on the device.
+
 .TP
 \fB\-\-lock\-video\-orientation\fR[=\fIvalue\fR]
 Lock video orientation to \fIvalue\fR. Possible values are "unlocked", "initial" (locked to the initial orientation), 0, 1, 2 and 3. Natural device orientation is 0, and each increment adds a 90 degrees rotation counterclockwise.

app/src/cli.c

@@ -69,6 +69,7 @@ enum {
     OPT_AUDIO_CODEC_OPTIONS,
     OPT_AUDIO_ENCODER,
     OPT_LIST_ENCODERS,
+    OPT_LIST_DISPLAYS,
 };
 
 struct sc_option {
@@ -198,10 +199,9 @@ static const struct sc_option options[] = {
         .longopt_id = OPT_DISPLAY_ID,
         .longopt = "display",
         .argdesc = "id",
-        .text = "Specify the display id to mirror.\n"
+        .text = "Specify the device display id to mirror.\n"
-                "The list of possible display ids can be listed by:\n"
+                "The available display ids can be listed by:\n"
-                "    adb shell dumpsys display\n"
+                "    scrcpy --list-displays\n"
-                "(search \"mDisplayId=\" in the output)\n"
                 "Default is 0.",
     },
     {
@@ -272,6 +272,11 @@ static const struct sc_option options[] = {
                 "This is a workaround for some devices not behaving as "
                 "expected when setting the device clipboard programmatically.",
     },
+    {
+        .longopt_id = OPT_LIST_DISPLAYS,
+        .longopt = "list-displays",
+        .text = "List device displays.",
+    },
     {
         .longopt_id = OPT_LIST_ENCODERS,
         .longopt = "list-encoders",
@@ -1803,6 +1808,9 @@ parse_args_with_getopt(struct scrcpy_cli_args *args, int argc, char *argv[],
             case OPT_LIST_ENCODERS:
                 opts->list_encoders = true;
                 break;
+            case OPT_LIST_DISPLAYS:
+                opts->list_displays = true;
+                break;
             default:
                 // getopt prints the error message on stderr
                 return false;

app/src/options.c

@@ -73,4 +73,5 @@ const struct scrcpy_options scrcpy_options_default = {
     .power_on = true,
     .audio = true,
     .list_encoders = false,
+    .list_displays = false,
 };

app/src/options.h

@@ -155,6 +155,7 @@ struct scrcpy_options {
     bool power_on;
     bool audio;
     bool list_encoders;
+    bool list_displays;
 };
 
 extern const struct scrcpy_options scrcpy_options_default;

app/src/scrcpy.c

@@ -353,6 +353,7 @@ scrcpy(struct scrcpy_options *options) {
         .cleanup = options->cleanup,
         .power_on = options->power_on,
         .list_encoders = options->list_encoders,
+        .list_displays = options->list_displays,
     };
 
     static const struct sc_server_callbacks cbs = {
@@ -370,7 +371,7 @@ scrcpy(struct scrcpy_options *options) {
 
     server_started = true;
 
-    if (options->list_encoders) {
+    if (options->list_encoders || options->list_displays) {
         bool ok = await_for_server(NULL);
         ret = ok ? SCRCPY_EXIT_SUCCESS : SCRCPY_EXIT_FAILURE;
         goto end;

app/src/server.c

@@ -303,6 +303,9 @@ execute_server(struct sc_server *server,
     if (params->list_encoders) {
         ADD_PARAM("list_encoders=true");
     }
+    if (params->list_displays) {
+        ADD_PARAM("list_displays=true");
+    }
 
 #undef ADD_PARAM
 
@@ -856,9 +859,9 @@ run_server(void *data) {
         goto error_connection_failed;
     }
 
-    // If --list-encoders is passed, then the server just prints the encoders
+    // If --list-* is passed, then the server just prints the requested data
     // then exits.
-    if (params->list_encoders) {
+    if (params->list_encoders || params->list_displays) {
         sc_pid pid = execute_server(server, params);
         if (pid == SC_PROCESS_NONE) {
             goto error_connection_failed;

app/src/server.h

@@ -56,6 +56,7 @@ struct sc_server_params {
     bool cleanup;
     bool power_on;
     bool list_encoders;
+    bool list_displays;
 };
 
 struct sc_server {

server/src/main/java/com/genymobile/scrcpy/Device.java

@@ -65,7 +65,7 @@ public final class Device {
         displayId = options.getDisplayId();
         DisplayInfo displayInfo = ServiceManager.getDisplayManager().getDisplayInfo(displayId);
         if (displayInfo == null) {
-            Ln.e(buildUnknownDisplayIdMessage(displayId));
+            Ln.e("Display " + displayId + " not found\n" + LogUtils.buildDisplayListMessage());
             throw new ConfigurationException("Unknown display id: " + displayId);
         }
 
@@ -130,18 +130,6 @@ public final class Device {
         }
     }
 
-    private static String buildUnknownDisplayIdMessage(int displayId) {
-        StringBuilder msg = new StringBuilder("Display ").append(displayId).append(" not found");
-        int[] displayIds = ServiceManager.getDisplayManager().getDisplayIds();
-        if (displayIds != null && displayIds.length > 0) {
-            msg.append("\nTry to use one of the available display ids:");
-            for (int id : displayIds) {
-                msg.append("\n    scrcpy --display=").append(id);
-            }
-        }
-        return msg.toString();
-    }
-
     public synchronized void setMaxSize(int newMaxSize) {
         maxSize = newMaxSize;
         screenInfo = ScreenInfo.computeScreenInfo(screenInfo.getReverseVideoRotation(), deviceSize, crop, newMaxSize, lockVideoOrientation);

server/src/main/java/com/genymobile/scrcpy/LogUtils.java

@@ -1,5 +1,7 @@
 package com.genymobile.scrcpy;
 
+import com.genymobile.scrcpy.wrappers.ServiceManager;
+
 import java.util.List;
 
 public final class LogUtils {
@@ -35,4 +37,17 @@ public final class LogUtils {
         }
         return builder.toString();
     }
+
+    public static String buildDisplayListMessage() {
+        StringBuilder builder = new StringBuilder("List of displays:");
+        int[] displayIds = ServiceManager.getDisplayManager().getDisplayIds();
+        if (displayIds == null || displayIds.length == 0) {
+            builder.append("\n    (none)");
+        } else {
+            for (int id : displayIds) {
+                builder.append("\n    --display=").append(id);
+            }
+        }
+        return builder.toString();
+    }
 }

server/src/main/java/com/genymobile/scrcpy/Options.java

@@ -34,6 +34,7 @@ public class Options {
     private boolean powerOn = true;
 
     private boolean listEncoders;
+    private boolean listDisplays;
 
     // Options not used by the scrcpy client, but useful to use scrcpy-server directly
     private boolean sendDeviceMeta = true; // send device name and size
@@ -249,6 +250,14 @@ public class Options {
         this.listEncoders = listEncoders;
     }
 
+    public boolean getListDisplays() {
+        return listDisplays;
+    }
+
+    public void setListDisplays(boolean listDisplays) {
+        this.listDisplays = listDisplays;
+    }
+
     public boolean getSendDeviceMeta() {
         return sendDeviceMeta;
     }

server/src/main/java/com/genymobile/scrcpy/Server.java

@@ -295,6 +295,10 @@ public final class Server {
                     boolean listEncoders = Boolean.parseBoolean(value);
                     options.setListEncoders(listEncoders);
                     break;
+                case "list_displays":
+                    boolean listDisplays = Boolean.parseBoolean(value);
+                    options.setListDisplays(listDisplays);
+                    break;
                 case "send_device_meta":
                     boolean sendDeviceMeta = Boolean.parseBoolean(value);
                     options.setSendDeviceMeta(sendDeviceMeta);
@@ -354,14 +358,19 @@ public final class Server {
 
         Ln.initLogLevel(options.getLogLevel());
 
-        if (options.getListEncoders()) {
+        if (options.getListEncoders() || options.getListDisplays()) {
             if (options.getCleanup()) {
                 CleanUp.unlinkSelf();
             }
 
+            if (options.getListEncoders()) {
                 Ln.i(LogUtils.buildVideoEncoderListMessage());
                 Ln.i(LogUtils.buildAudioEncoderListMessage());
-            // Just print the available encoders, do not mirror
+            }
+            if (options.getListDisplays()) {
+                Ln.i(LogUtils.buildDisplayListMessage());
+            }
+            // Just print the requested data, do not mirror
             return;
         }