Add crop feature

Add an option to crop the screen on the server. This allows to mirror
only part of the device screen.

app/src/main.c

@@ -10,6 +10,7 @@
 
 struct args {
     const char *serial;
+    const char *crop;
     SDL_bool help;
     SDL_bool version;
     SDL_bool show_touches;
@@ -29,6 +30,12 @@ static void usage(const char *arg0) {
         "        Unit suffixes are supported: 'K' (x1000) and 'M' (x1000000).\n"
         "        Default is %d.\n"
         "\n"
+        "    -c, --crop width:height:x:y\n"
+        "        Crop the device screen on the server.\n"
+        "        The values are expressed in the device natural orientation\n"
+        "        (typically, portrait for a phone, landscape for a tablet).\n"
+        "        Any --max-size value is computed on the cropped size.\n"
+        "\n"
         "    -h, --help\n"
         "        Print this help.\n"
         "\n"
@@ -192,6 +199,7 @@ static SDL_bool parse_port(char *optarg, Uint16 *port) {
 static SDL_bool parse_args(struct args *args, int argc, char *argv[]) {
     static const struct option long_options[] = {
         {"bit-rate",     required_argument, NULL, 'b'},
+        {"crop",         required_argument, NULL, 'c'},
         {"help",         no_argument,       NULL, 'h'},
         {"max-size",     required_argument, NULL, 'm'},
         {"port",         required_argument, NULL, 'p'},
@@ -201,13 +209,16 @@ static SDL_bool parse_args(struct args *args, int argc, char *argv[]) {
         {NULL,           0,                 NULL, 0  },
     };
     int c;
-    while ((c = getopt_long(argc, argv, "b:hm:p:s:tv", long_options, NULL)) != -1) {
+    while ((c = getopt_long(argc, argv, "b:c:hm:p:s:tv", long_options, NULL)) != -1) {
         switch (c) {
             case 'b':
                 if (!parse_bit_rate(optarg, &args->bit_rate)) {
                     return SDL_FALSE;
                 }
                 break;
+            case 'c':
+                args->crop = optarg;
+                break;
             case 'h':
                 args->help = SDL_TRUE;
                 break;
@@ -253,6 +264,7 @@ int main(int argc, char *argv[]) {
 #endif
     struct args args = {
         .serial = NULL,
+        .crop = NULL,
         .help = SDL_FALSE,
         .version = SDL_FALSE,
         .show_touches = SDL_FALSE,
@@ -288,6 +300,7 @@ int main(int argc, char *argv[]) {
 
     struct scrcpy_options options = {
         .serial = args.serial,
+        .crop = args.crop,
         .port = args.port,
         .max_size = args.max_size,
         .bit_rate = args.bit_rate,

app/src/scrcpy.c

@@ -126,7 +126,7 @@ static void wait_show_touches(process_t process) {
 
 SDL_bool scrcpy(const struct scrcpy_options *options) {
     if (!server_start(&server, options->serial, options->port,
-                      options->max_size, options->bit_rate)) {
+                      options->max_size, options->bit_rate, options->crop)) {
         return SDL_FALSE;
     }
 

app/src/scrcpy.h

@@ -5,6 +5,7 @@
 
 struct scrcpy_options {
     const char *serial;
+    const char *crop;
     Uint16 port;
     Uint16 max_size;
     Uint32 bit_rate;

app/src/server.c

@@ -77,7 +77,8 @@ static SDL_bool disable_tunnel(struct server *server) {
 }
 
 static process_t execute_server(const char *serial,
-                                Uint16 max_size, Uint32 bit_rate, SDL_bool tunnel_forward) {
+                                Uint16 max_size, Uint32 bit_rate,
+                                const char *crop, SDL_bool tunnel_forward) {
     char max_size_string[6];
     char bit_rate_string[11];
     sprintf(max_size_string, "%"PRIu16, max_size);
@@ -91,6 +92,7 @@ static process_t execute_server(const char *serial,
         max_size_string,
         bit_rate_string,
         tunnel_forward ? "true" : "false",
+        crop ? crop : "",
     };
     return adb_execute(serial, cmd, sizeof(cmd) / sizeof(cmd[0]));
 }
@@ -147,7 +149,7 @@ void server_init(struct server *server) {
 }
 
 SDL_bool server_start(struct server *server, const char *serial, Uint16 local_port,
-                      Uint16 max_size, Uint32 bit_rate) {
+                      Uint16 max_size, Uint32 bit_rate, const char *crop) {
     server->local_port = local_port;
 
     if (serial) {
@@ -188,7 +190,8 @@ SDL_bool server_start(struct server *server, const char *serial, Uint16 local_po
     }
 
     // server will connect to our server socket
-    server->process = execute_server(serial, max_size, bit_rate, server->tunnel_forward);
+    server->process = execute_server(serial, max_size, bit_rate, crop,
+                                     server->tunnel_forward);
     if (server->process == PROCESS_NONE) {
         if (!server->tunnel_forward) {
             close_socket(&server->server_socket);

app/src/server.h

@@ -31,7 +31,7 @@ void server_init(struct server *server);
 
 // push, enable tunnel et start the server
 SDL_bool server_start(struct server *server, const char *serial, Uint16 local_port,
-                      Uint16 max_size, Uint32 bit_rate);
+                      Uint16 max_size, Uint32 bit_rate, const char *crop);
 
 // block until the communication with the server is established
 socket_t server_connect_to(struct server *server);