Add scrcpy window without video playback

Add the possibility to only control the device with any keyboard and
mouse mode without screen mirroring:

    scrcpy -KM --no-video --no-audio

This is different from OTG mode, which does not require USB debugging at
all. Here, the standard mode is used but with the possibility to disable
video playback.

By default, always open a window (even without video playback), and add
an option --no-window.

Fixes #4727 <https://github.com/Genymobile/scrcpy/issues/4727>
Fixes #4793 <https://github.com/Genymobile/scrcpy/issues/4793>
PR #4868 <https://github.com/Genymobile/scrcpy/pull/4868>

app/scrcpy.1

@@ -316,6 +316,10 @@ Disable video forwarding.
 .B \-\-no\-video\-playback
 Disable video playback on the computer.
 
+.TP
+.B \-\-no\-window
+Disable scrcpy window. Implies --no-video-playback and --no-control.
+
 .TP
 .BI "\-\-orientation " value
 Same as --display-orientation=value --record-orientation=value.

app/src/cli.c

@@ -97,6 +97,7 @@ enum {
     OPT_MOUSE,
     OPT_HID_KEYBOARD_DEPRECATED,
     OPT_HID_MOUSE_DEPRECATED,
+    OPT_NO_WINDOW,
 };
 
 struct sc_option {
@@ -566,6 +567,12 @@ static const struct sc_option options[] = {
         .longopt = "no-video-playback",
         .text = "Disable video playback on the computer.",
     },
+    {
+        .longopt_id = OPT_NO_WINDOW,
+        .longopt = "no-window",
+        .text = "Disable scrcpy window. Implies --no-video-playback and "
+                "--no-control.",
+    },
     {
         .longopt_id = OPT_ORIENTATION,
         .longopt = "orientation",
@@ -2486,6 +2493,9 @@ parse_args_with_getopt(struct scrcpy_cli_args *args, int argc, char *argv[],
             case OPT_CAMERA_HIGH_SPEED:
                 opts->camera_high_speed = true;
                 break;
+            case OPT_NO_WINDOW:
+                opts->window = false;
+                break;
             default:
                 // getopt prints the error message on stderr
                 return false;
@@ -2523,6 +2533,12 @@ parse_args_with_getopt(struct scrcpy_cli_args *args, int argc, char *argv[],
     v4l2 = !!opts->v4l2_device;
 #endif
 
+    if (!opts->window) {
+        // Without window, there cannot be any video playback or control
+        opts->video_playback = false;
+        opts->control = false;
+    }
+
     if (!opts->video) {
         opts->video_playback = false;
         // Do not power on the device on start if video capture is disabled
@@ -2544,8 +2560,8 @@ parse_args_with_getopt(struct scrcpy_cli_args *args, int argc, char *argv[],
         opts->audio = false;
     }
 
-    if (!opts->video && !opts->audio && !otg) {
-        LOGE("No video, no audio, no OTG: nothing to do");
+    if (!opts->video && !opts->audio && !opts->control && !otg) {
+        LOGE("No video, no audio, no control, no OTG: nothing to do");
         return false;
     }
 
@@ -2588,13 +2604,26 @@ parse_args_with_getopt(struct scrcpy_cli_args *args, int argc, char *argv[],
     }
 #endif
 
-    if (opts->keyboard_input_mode == SC_KEYBOARD_INPUT_MODE_AUTO) {
-        opts->keyboard_input_mode = otg ? SC_KEYBOARD_INPUT_MODE_AOA
-                                        : SC_KEYBOARD_INPUT_MODE_SDK;
-    }
-    if (opts->mouse_input_mode == SC_MOUSE_INPUT_MODE_AUTO) {
-        opts->mouse_input_mode = otg ? SC_MOUSE_INPUT_MODE_AOA
-                                     : SC_MOUSE_INPUT_MODE_SDK;
+    if (opts->control) {
+        if (opts->keyboard_input_mode == SC_KEYBOARD_INPUT_MODE_AUTO) {
+            opts->keyboard_input_mode = otg ? SC_KEYBOARD_INPUT_MODE_AOA
+                                            : SC_KEYBOARD_INPUT_MODE_SDK;
+        }
+        if (opts->mouse_input_mode == SC_MOUSE_INPUT_MODE_AUTO) {
+            if (otg) {
+                opts->mouse_input_mode = SC_MOUSE_INPUT_MODE_AOA;
+            } else if (!opts->video_playback) {
+                LOGI("No video mirroring, SDK mouse disabled (you might want "
+                     "--mouse=uhid)");
+                opts->mouse_input_mode = SC_MOUSE_INPUT_MODE_DISABLED;
+            } else {
+                opts->mouse_input_mode = SC_MOUSE_INPUT_MODE_SDK;
+            }
+        } else if (opts->mouse_input_mode == SC_MOUSE_INPUT_MODE_SDK
+                    && !opts->video_playback) {
+            LOGE("SDK mouse mode requires video playback. Try --mouse=uhid.");
+            return false;
+        }
     }
 
     if (otg) {

app/src/display.c

@@ -5,8 +5,36 @@
 
 #include "util/log.h"
 
+static bool
+sc_display_init_novideo_icon(struct sc_display *display,
+                             SDL_Surface *icon_novideo) {
+    assert(icon_novideo);
+
+    if (SDL_RenderSetLogicalSize(display->renderer,
+                                 icon_novideo->w, icon_novideo->h)) {
+        LOGW("Could not set renderer logical size: %s", SDL_GetError());
+        // don't fail
+    }
+
+    display->texture = SDL_CreateTextureFromSurface(display->renderer,
+                                                    icon_novideo);
+    if (!display->texture) {
+        LOGE("Could not create texture: %s", SDL_GetError());
+        return false;
+    }
+
+    SDL_RenderClear(display->renderer);
+    if (display->texture) {
+        SDL_RenderCopy(display->renderer, display->texture, NULL, NULL);
+    }
+    SDL_RenderPresent(display->renderer);
+
+    return true;
+}
+
 bool
-sc_display_init(struct sc_display *display, SDL_Window *window, bool mipmaps) {
+sc_display_init(struct sc_display *display, SDL_Window *window,
+                SDL_Surface *icon_novideo, bool mipmaps) {
     display->renderer =
         SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
     if (!display->renderer) {
@@ -68,6 +96,18 @@ sc_display_init(struct sc_display *display, SDL_Window *window, bool mipmaps) {
     display->pending.frame = NULL;
     display->has_frame = false;
 
+    if (icon_novideo) {
+        // Without video, set a static scrcpy icon as window content
+        bool ok = sc_display_init_novideo_icon(display, icon_novideo);
+        if (!ok) {
+#ifdef SC_DISPLAY_FORCE_OPENGL_CORE_PROFILE
+            SDL_GL_DeleteContext(display->gl_context);
+#endif
+            SDL_DestroyRenderer(display->renderer);
+            return false;
+        }
+    }
+
     return true;
 }
 

app/src/display.h

@@ -44,7 +44,8 @@ enum sc_display_result {
 };
 
 bool
-sc_display_init(struct sc_display *display, SDL_Window *window, bool mipmaps);
+sc_display_init(struct sc_display *display, SDL_Window *window,
+                SDL_Surface *icon_novideo, bool mipmaps);
 
 void
 sc_display_destroy(struct sc_display *display);

app/src/input_manager.c

@@ -403,6 +403,7 @@ sc_input_manager_process_key(struct sc_input_manager *im,
     // controller is NULL if --no-control is requested
     bool control = im->controller;
     bool paused = im->screen->paused;
+    bool video = im->screen->video;
 
     SDL_Keycode keycode = event->keysym.sym;
     uint16_t mod = event->keysym.mod;
@@ -462,13 +463,13 @@ sc_input_manager_process_key(struct sc_input_manager *im,
                 }
                 return;
             case SDLK_z:
-                if (down && !repeat) {
+                if (video && down && !repeat) {
                     sc_screen_set_paused(im->screen, !shift);
                 }
                 return;
             case SDLK_DOWN:
                 if (shift) {
-                    if (!repeat && down) {
+                    if (video && !repeat && down) {
                         apply_orientation_transform(im,
                                                     SC_ORIENTATION_FLIP_180);
                     }
@@ -479,7 +480,7 @@ sc_input_manager_process_key(struct sc_input_manager *im,
                 return;
             case SDLK_UP:
                 if (shift) {
-                    if (!repeat && down) {
+                    if (video && !repeat && down) {
                         apply_orientation_transform(im,
                                                     SC_ORIENTATION_FLIP_180);
                     }
@@ -489,7 +490,7 @@ sc_input_manager_process_key(struct sc_input_manager *im,
                 }
                 return;
             case SDLK_LEFT:
-                if (!repeat && down) {
+                if (video && !repeat && down) {
                     if (shift) {
                         apply_orientation_transform(im,
                                                     SC_ORIENTATION_FLIP_0);
@@ -500,7 +501,7 @@ sc_input_manager_process_key(struct sc_input_manager *im,
                 }
                 return;
             case SDLK_RIGHT:
-                if (!repeat && down) {
+                if (video && !repeat && down) {
                     if (shift) {
                         apply_orientation_transform(im,
                                                     SC_ORIENTATION_FLIP_0);
@@ -533,22 +534,22 @@ sc_input_manager_process_key(struct sc_input_manager *im,
                 }
                 return;
             case SDLK_f:
-                if (!shift && !repeat && down) {
+                if (video && !shift && !repeat && down) {
                     sc_screen_switch_fullscreen(im->screen);
                 }
                 return;
             case SDLK_w:
-                if (!shift && !repeat && down) {
+                if (video && !shift && !repeat && down) {
                     sc_screen_resize_to_fit(im->screen);
                 }
                 return;
             case SDLK_g:
-                if (!shift && !repeat && down) {
+                if (video && !shift && !repeat && down) {
                     sc_screen_resize_to_pixel_perfect(im->screen);
                 }
                 return;
             case SDLK_i:
-                if (!shift && !repeat && down) {
+                if (video && !shift && !repeat && down) {
                     switch_fps_counter_state(im);
                 }
                 return;

app/src/options.c

@@ -89,6 +89,7 @@ const struct scrcpy_options scrcpy_options_default = {
     .kill_adb_on_close = false,
     .camera_high_speed = false,
     .list = 0,
+    .window = true,
 };
 
 enum sc_orientation

app/src/options.h

@@ -279,6 +279,7 @@ struct scrcpy_options {
 #define SC_OPTION_LIST_CAMERAS 0x4
 #define SC_OPTION_LIST_CAMERA_SIZES 0x8
     uint8_t list;
+    bool window;
 };
 
 extern const struct scrcpy_options scrcpy_options_default;

app/src/scrcpy.c

@@ -430,7 +430,7 @@ scrcpy(struct scrcpy_options *options) {
     assert(!options->video_playback || options->video);
     assert(!options->audio_playback || options->audio);
 
-    if (options->video_playback ||
+    if (options->window ||
             (options->control && options->clipboard_autosync)) {
         // Initialize the video subsystem even if --no-video or
         // --no-video-playback is passed so that clipboard synchronization
@@ -684,11 +684,12 @@ scrcpy(struct scrcpy_options *options) {
     // There is a controller if and only if control is enabled
     assert(options->control == !!controller);
 
-    if (options->video_playback) {
+    if (options->window) {
         const char *window_title =
             options->window_title ? options->window_title : info->device_name;
 
         struct sc_screen_params screen_params = {
+            .video = options->video_playback,
             .controller = controller,
             .fp = fp,
             .kp = kp,
@@ -710,12 +711,15 @@ scrcpy(struct scrcpy_options *options) {
             .start_fps_counter = options->start_fps_counter,
         };
 
-        struct sc_frame_source *src = &s->video_decoder.frame_source;
-        if (options->display_buffer) {
-            sc_delay_buffer_init(&s->display_buffer, options->display_buffer,
-                                 true);
-            sc_frame_source_add_sink(src, &s->display_buffer.frame_sink);
-            src = &s->display_buffer.frame_source;
+        struct sc_frame_source *src;
+        if (options->video_playback) {
+            src = &s->video_decoder.frame_source;
+            if (options->display_buffer) {
+                sc_delay_buffer_init(&s->display_buffer,
+                                     options->display_buffer, true);
+                sc_frame_source_add_sink(src, &s->display_buffer.frame_sink);
+                src = &s->display_buffer.frame_source;
+            }
         }
 
         if (!sc_screen_init(&s->screen, &screen_params)) {
@@ -723,7 +727,9 @@ scrcpy(struct scrcpy_options *options) {
         }
         screen_initialized = true;
 
-        sc_frame_source_add_sink(src, &s->screen.frame_sink);
+        if (options->video_playback) {
+            sc_frame_source_add_sink(src, &s->screen.frame_sink);
+        }
     }
 
     if (options->audio_playback) {

app/src/screen.c

@@ -205,6 +205,8 @@ sc_screen_toggle_mouse_capture(struct sc_screen *screen) {
 
 static void
 sc_screen_update_content_rect(struct sc_screen *screen) {
+    assert(screen->video);
+
     int dw;
     int dh;
     SDL_GL_GetDrawableSize(screen->window, &dw, &dh);
@@ -246,6 +248,8 @@ sc_screen_update_content_rect(struct sc_screen *screen) {
 // changed, so that the content rectangle is recomputed
 static void
 sc_screen_render(struct sc_screen *screen, bool update_content_rect) {
+    assert(screen->video);
+
     if (update_content_rect) {
         sc_screen_update_content_rect(screen);
     }
@@ -326,6 +330,7 @@ sc_screen_frame_sink_close(struct sc_frame_sink *sink) {
 static bool
 sc_screen_frame_sink_push(struct sc_frame_sink *sink, const AVFrame *frame) {
     struct sc_screen *screen = DOWNCAST(sink);
+    assert(screen->video);
 
     bool previous_skipped;
     bool ok = sc_frame_buffer_push(&screen->fb, frame, &previous_skipped);
@@ -365,6 +370,8 @@ sc_screen_init(struct sc_screen *screen,
     screen->paused = false;
     screen->resume_frame = NULL;
 
+    screen->video = params->video;
+
     screen->req.x = params->window_x;
     screen->req.y = params->window_y;
     screen->req.width = params->window_width;
@@ -387,9 +394,7 @@ sc_screen_init(struct sc_screen *screen,
              sc_orientation_get_name(screen->orientation));
     }
 
-    uint32_t window_flags = SDL_WINDOW_HIDDEN
-                          | SDL_WINDOW_RESIZABLE
-                          | SDL_WINDOW_ALLOW_HIGHDPI;
+    uint32_t window_flags = SDL_WINDOW_ALLOW_HIGHDPI;
     if (params->always_on_top) {
         window_flags |= SDL_WINDOW_ALWAYS_ON_TOP;
     }
@@ -397,25 +402,58 @@ sc_screen_init(struct sc_screen *screen,
         window_flags |= SDL_WINDOW_BORDERLESS;
     }
 
+    const char *title = params->window_title;
+    assert(title);
+
+    int x = SDL_WINDOWPOS_UNDEFINED;
+    int y = SDL_WINDOWPOS_UNDEFINED;
+    int width = 256;
+    int height = 256;
+    if (params->video) {
+        // The window will be shown on first frame
+        window_flags |= SDL_WINDOW_HIDDEN
+                      | SDL_WINDOW_RESIZABLE;
+        if (params->window_x != SC_WINDOW_POSITION_UNDEFINED) {
+            x = params->window_x;
+        }
+        if (params->window_y != SC_WINDOW_POSITION_UNDEFINED) {
+            y = params->window_y;
+        }
+        if (params->window_width) {
+            width = params->window_width;
+        }
+        if (params->window_height) {
+            height = params->window_height;
+        }
+    }
+
     // The window will be positioned and sized on first video frame
-    screen->window =
-        SDL_CreateWindow(params->window_title, 0, 0, 0, 0, window_flags);
+    screen->window = SDL_CreateWindow(title, x, y, width, height, window_flags);
     if (!screen->window) {
         LOGE("Could not create window: %s", SDL_GetError());
         goto error_destroy_fps_counter;
     }
 
-    ok = sc_display_init(&screen->display, screen->window, params->mipmaps);
-    if (!ok) {
-        goto error_destroy_window;
-    }
-
     SDL_Surface *icon = scrcpy_icon_load();
     if (icon) {
         SDL_SetWindowIcon(screen->window, icon);
-        scrcpy_icon_destroy(icon);
-    } else {
+    } else if (params->video) {
+        // just a warning
         LOGW("Could not load icon");
+    } else {
+        // without video, the icon is used as window content, it must be present
+        LOGE("Could not load icon");
+        goto error_destroy_fps_counter;
+    }
+
+    SDL_Surface *icon_novideo = params->video ? NULL : icon;
+    ok = sc_display_init(&screen->display, screen->window, icon_novideo,
+                         params->mipmaps);
+    if (icon) {
+        scrcpy_icon_destroy(icon);
+    }
+    if (!ok) {
+        goto error_destroy_window;
     }
 
     screen->frame = av_frame_alloc();
@@ -454,6 +492,11 @@ sc_screen_init(struct sc_screen *screen,
     screen->open = false;
 #endif
 
+    if (!screen->video && sc_screen_is_relative_mode(screen)) {
+        // Capture mouse immediately if video mirroring is disabled
+        sc_screen_set_mouse_capture(screen, true);
+    }
+
     return true;
 
 error_destroy_display:
@@ -524,6 +567,8 @@ sc_screen_destroy(struct sc_screen *screen) {
 static void
 resize_for_content(struct sc_screen *screen, struct sc_size old_content_size,
                    struct sc_size new_content_size) {
+    assert(screen->video);
+
     struct sc_size window_size = get_window_size(screen);
     struct sc_size target_size = {
         .width = (uint32_t) window_size.width * new_content_size.width
@@ -537,6 +582,8 @@ resize_for_content(struct sc_screen *screen, struct sc_size old_content_size,
 
 static void
 set_content_size(struct sc_screen *screen, struct sc_size new_content_size) {
+    assert(screen->video);
+
     if (!screen->fullscreen && !screen->maximized && !screen->minimized) {
         resize_for_content(screen, screen->content_size, new_content_size);
     } else if (!screen->resize_pending) {
@@ -551,6 +598,8 @@ set_content_size(struct sc_screen *screen, struct sc_size new_content_size) {
 
 static void
 apply_pending_resize(struct sc_screen *screen) {
+    assert(screen->video);
+
     assert(!screen->fullscreen);
     assert(!screen->maximized);
     assert(!screen->minimized);
@@ -564,6 +613,8 @@ apply_pending_resize(struct sc_screen *screen) {
 void
 sc_screen_set_orientation(struct sc_screen *screen,
                           enum sc_orientation orientation) {
+    assert(screen->video);
+
     if (orientation == screen->orientation) {
         return;
     }
@@ -598,6 +649,8 @@ sc_screen_init_size(struct sc_screen *screen) {
 // recreate the texture and resize the window if the frame size has changed
 static enum sc_display_result
 prepare_for_frame(struct sc_screen *screen, struct sc_size new_frame_size) {
+    assert(screen->video);
+
     if (screen->frame_size.width == new_frame_size.width
             && screen->frame_size.height == new_frame_size.height) {
         return SC_DISPLAY_RESULT_OK;
@@ -617,6 +670,8 @@ prepare_for_frame(struct sc_screen *screen, struct sc_size new_frame_size) {
 
 static bool
 sc_screen_apply_frame(struct sc_screen *screen) {
+    assert(screen->video);
+
     sc_fps_counter_add_rendered_frame(&screen->fps_counter);
 
     AVFrame *frame = screen->frame;
@@ -656,6 +711,8 @@ sc_screen_apply_frame(struct sc_screen *screen) {
 
 static bool
 sc_screen_update_frame(struct sc_screen *screen) {
+    assert(screen->video);
+
     if (screen->paused) {
         if (!screen->resume_frame) {
             screen->resume_frame = av_frame_alloc();
@@ -677,6 +734,8 @@ sc_screen_update_frame(struct sc_screen *screen) {
 
 void
 sc_screen_set_paused(struct sc_screen *screen, bool paused) {
+    assert(screen->video);
+
     if (!paused && !screen->paused) {
         // nothing to do
         return;
@@ -704,6 +763,8 @@ sc_screen_set_paused(struct sc_screen *screen, bool paused) {
 
 void
 sc_screen_switch_fullscreen(struct sc_screen *screen) {
+    assert(screen->video);
+
     uint32_t new_mode = screen->fullscreen ? 0 : SDL_WINDOW_FULLSCREEN_DESKTOP;
     if (SDL_SetWindowFullscreen(screen->window, new_mode)) {
         LOGW("Could not switch fullscreen mode: %s", SDL_GetError());
@@ -721,6 +782,8 @@ sc_screen_switch_fullscreen(struct sc_screen *screen) {
 
 void
 sc_screen_resize_to_fit(struct sc_screen *screen) {
+    assert(screen->video);
+
     if (screen->fullscreen || screen->maximized || screen->minimized) {
         return;
     }
@@ -745,6 +808,8 @@ sc_screen_resize_to_fit(struct sc_screen *screen) {
 
 void
 sc_screen_resize_to_pixel_perfect(struct sc_screen *screen) {
+    assert(screen->video);
+
     if (screen->fullscreen || screen->minimized) {
         return;
     }
@@ -788,6 +853,8 @@ sc_screen_handle_event(struct sc_screen *screen, const SDL_Event *event) {
             return true;
         }
         case SDL_WINDOWEVENT:
+            // !video implies !has_frame
+            assert(screen->video || !screen->has_frame);
             if (!screen->has_frame) {
                 // Do nothing
                 return true;

app/src/screen.h

@@ -26,6 +26,8 @@ struct sc_screen {
     bool open; // track the open/close state to assert correct behavior
 #endif
 
+    bool video;
+
     struct sc_display display;
     struct sc_input_manager im;
     struct sc_frame_buffer fb;
@@ -70,6 +72,8 @@ struct sc_screen {
 };
 
 struct sc_screen_params {
+    bool video;
+
     struct sc_controller *controller;
     struct sc_file_pusher *fp;
     struct sc_key_processor *kp;