Add --rotation command-line option

In addition to Ctrl+Left and Ctrl+Right shortcuts, add a command-line
parameter to set the initial rotation.

README.md

@@ -340,6 +340,33 @@ scrcpy -f  # short version
 
 Fullscreen can then be toggled dynamically with `Ctrl`+`f`.
 
+#### Rotation
+
+The window may be rotated:
+
+```bash
+scrcpy --rotation 1
+```
+
+Possibles values are:
+ - `0`: no rotation
+ - `1`: 90 degrees counterclockwise
+ - `2`: 180 degrees
+ - `3`: 90 degrees clockwise
+
+The rotation can also be changed dynamically with `Ctrl`+`←` _(left)_ and
+`Ctrl`+`→` _(right)_.
+
+Note that _scrcpy_ manages 3 different rotations:
+ - `Ctrl`+`r` requests the device to switch between portrait and landscape (the
+   current running app may refuse, if it does support the requested
+   orientation).
+ - `--lock-video-orientation` changes the mirroring orientation (the orientation
+   of the video sent from the device to the computer. This affects the
+   recording.
+ - `--rotation` (or `Ctrl`+`←`/`Ctrl`+`→`) rotates only the window content. This
+   affects only the display, not the recording.
+
 
 ### Other mirroring options
 

app/scrcpy.1

@@ -110,6 +110,10 @@ Force recording format (either mp4 or mkv).
 .B \-\-render\-expired\-frames
 By default, to minimize latency, scrcpy always renders the last available decoded frame, and drops any previous ones. This flag forces to render all frames, at a cost of a possible increased latency.
 
+.TP
+.BI "\-\-rotation " value
+Set the initial display rotation. Possibles values are 0, 1, 2 and 3. Each increment adds a 90 degrees rotation counterclockwise.
+
 .TP
 .BI "\-s, \-\-serial " number
 The device serial number. Mandatory only if several devices are connected to adb.

app/src/cli.c

@@ -104,6 +104,11 @@ scrcpy_print_usage(const char *arg0) {
         "        This flag forces to render all frames, at a cost of a\n"
         "        possible increased latency.\n"
         "\n"
+        "    --rotation value\n"
+        "        Set the initial display rotation.\n"
+        "        Possibles values are 0, 1, 2 and 3. Each increment adds a 90\n"
+        "        degrees rotation counterclockwise.\n"
+        "\n"
         "    -s, --serial serial\n"
         "        The device serial number. Mandatory only if several devices\n"
         "        are connected to adb.\n"
@@ -316,6 +321,18 @@ parse_lock_video_orientation(const char *s, int8_t *lock_video_orientation) {
     return true;
 }
 
+static bool
+parse_rotation(const char *s, uint8_t *rotation) {
+    long value;
+    bool ok = parse_integer_arg(s, &value, false, 0, 3, "rotation");
+    if (!ok) {
+        return false;
+    }
+
+    *rotation = (uint8_t) value;
+    return true;
+}
+
 static bool
 parse_window_position(const char *s, int16_t *position) {
     // special value for "auto"
@@ -435,6 +452,7 @@ guess_record_format(const char *filename) {
 #define OPT_MAX_FPS                1012
 #define OPT_LOCK_VIDEO_ORIENTATION 1013
 #define OPT_DISPLAY_ID             1014
+#define OPT_ROTATION               1015
 
 bool
 scrcpy_parse_args(struct scrcpy_cli_args *args, int argc, char *argv[]) {
@@ -455,6 +473,7 @@ scrcpy_parse_args(struct scrcpy_cli_args *args, int argc, char *argv[]) {
         {"push-target",            required_argument, NULL, OPT_PUSH_TARGET},
         {"record",                 required_argument, NULL, 'r'},
         {"record-format",          required_argument, NULL, OPT_RECORD_FORMAT},
+        {"rotation",               required_argument, NULL, OPT_ROTATION},
         {"render-expired-frames",  no_argument,       NULL,
                                                   OPT_RENDER_EXPIRED_FRAMES},
         {"serial",                 required_argument, NULL, 's'},
@@ -592,6 +611,11 @@ scrcpy_parse_args(struct scrcpy_cli_args *args, int argc, char *argv[]) {
             case OPT_PREFER_TEXT:
                 opts->prefer_text = true;
                 break;
+            case OPT_ROTATION:
+                if (!parse_rotation(optarg, &opts->rotation)) {
+                    return false;
+                }
+                break;
             default:
                 // getopt prints the error message on stderr
                 return false;

app/src/scrcpy.c

@@ -396,7 +396,8 @@ scrcpy(const struct scrcpy_options *options) {
                                    options->always_on_top, options->window_x,
                                    options->window_y, options->window_width,
                                    options->window_height,
-                                   options->window_borderless)) {
+                                   options->window_borderless,
+                                   options->rotation)) {
             goto end;
         }
 

app/src/scrcpy.h

@@ -21,6 +21,7 @@ struct scrcpy_options {
     uint32_t bit_rate;
     uint16_t max_fps;
     int8_t lock_video_orientation;
+    uint8_t rotation;
     int16_t window_x; // WINDOW_POSITION_UNDEFINED for "auto"
     int16_t window_y; // WINDOW_POSITION_UNDEFINED for "auto"
     uint16_t window_width;
@@ -52,6 +53,7 @@ struct scrcpy_options {
     .bit_rate = DEFAULT_BIT_RATE, \
     .max_fps = 0, \
     .lock_video_orientation = DEFAULT_LOCK_VIDEO_ORIENTATION, \
+    .rotation = 0, \
     .window_x = WINDOW_POSITION_UNDEFINED, \
     .window_y = WINDOW_POSITION_UNDEFINED, \
     .window_width = 0, \

app/src/screen.c

@@ -178,8 +178,13 @@ bool
 screen_init_rendering(struct screen *screen, const char *window_title,
                       struct size frame_size, bool always_on_top,
                       int16_t window_x, int16_t window_y, uint16_t window_width,
-                      uint16_t window_height, bool window_borderless) {
+                      uint16_t window_height, bool window_borderless,
+                      uint8_t rotation) {
     screen->frame_size = frame_size;
+    screen->rotation = rotation;
+    if (rotation) {
+        LOGI("Initial display rotation set to %u", rotation);
+    }
     struct size content_size =
         get_rotated_size(frame_size, screen->rotation);
 

app/src/screen.h

@@ -63,7 +63,8 @@ bool
 screen_init_rendering(struct screen *screen, const char *window_title,
                       struct size frame_size, bool always_on_top,
                       int16_t window_x, int16_t window_y, uint16_t window_width,
-                      uint16_t window_height, bool window_borderless);
+                      uint16_t window_height, bool window_borderless,
+                      uint8_t rotation);
 
 // show the window
 void