Handle resized video stream

Accept a parameter to limit the video size.

For instance, with "-m 960", the great side of the video will be scaled
down to 960 (if necessary), while the other side will be scaled down so
that the aspect ratio is preserved. Both dimensions must be a multiple
of 8, so black bands might be added, and the mouse positions must be
computed accordingly.

app/src/main.c

@@ -9,15 +9,16 @@
 struct args {
     const char *serial;
     Uint16 port;
+    Uint16 maximum_size;
 };
 
 int parse_args(struct args *args, int argc, char *argv[]) {
     int c;
-    while ((c = getopt(argc, argv, "p:")) != -1) {
+    while ((c = getopt(argc, argv, "p:m:")) != -1) {
         switch (c) {
         case 'p': {
             char *endptr;
-            long int value = strtol(optarg, &endptr, 0);
+            long value = strtol(optarg, &endptr, 0);
             if (*optarg == '\0' || *endptr != '\0') {
                 SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Invalid port: %s\n", optarg);
                 return -1;
@@ -29,6 +30,20 @@ int parse_args(struct args *args, int argc, char *argv[]) {
             args->port = (Uint16) value;
             break;
         }
+        case 'm': {
+            char *endptr;
+            long value = strtol(optarg, &endptr, 0);
+            if (*optarg == '\0' || *endptr != '\0') {
+                SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Invalid maximum size: %s\n", optarg);
+                return -1;
+            }
+            if (value & ~0xffff) {
+                SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Maximum size must be between 0 and 65535: %ld\n", value);
+                return -1;
+            }
+            args->maximum_size = (Uint16) value;
+            break;
+        }
         default:
             // getopt prints the error message on stderr
             return -1;
@@ -65,7 +80,7 @@ int main(int argc, char *argv[]) {
 
     SDL_LogSetAllPriority(SDL_LOG_PRIORITY_DEBUG);
 
-    res = scrcpy(args.serial, args.port) ? 0 : 1;
+    res = scrcpy(args.serial, args.port, args.maximum_size) ? 0 : 1;
 
     avformat_network_deinit(); // ignore failure
 

app/src/scrcpy.c

@@ -382,7 +382,7 @@ void event_loop(void) {
     }
 }
 
-SDL_bool scrcpy(const char *serial, Uint16 local_port) {
+SDL_bool scrcpy(const char *serial, Uint16 local_port, Uint16 maximum_size) {
     SDL_bool ret = 0;
 
     process_t push_proc = push_server(serial);
@@ -402,7 +402,7 @@ SDL_bool scrcpy(const char *serial, Uint16 local_port) {
     }
 
     // server will connect to our socket
-    process_t server = start_server(serial);
+    process_t server = start_server(serial, maximum_size);
     if (server == PROCESS_NONE) {
         ret = SDL_FALSE;
         SDLNet_TCP_Close(server_socket);

app/src/scrcpy.h

@@ -3,6 +3,6 @@
 
 #include <SDL2/SDL_stdinc.h>
 
-SDL_bool scrcpy(const char *serial, Uint16 local_port);
+SDL_bool scrcpy(const char *serial, Uint16 local_port, Uint16 maximum_size);
 
 #endif

app/src/server.c

@@ -21,13 +21,16 @@ process_t disable_tunnel(const char *serial) {
     return adb_reverse_remove(serial, SOCKET_NAME);
 }
 
-process_t start_server(const char *serial) {
+process_t start_server(const char *serial, Uint16 maximum_size) {
+    char maximum_size_string[6];
+    sprintf(maximum_size_string, "%d", maximum_size);
     const char *const cmd[] = {
         "shell",
         "CLASSPATH=/data/local/tmp/scrcpy-server.jar",
         "app_process",
         "/system/bin",
-        "com.genymobile.scrcpy.ScrCpyServer"
+        "com.genymobile.scrcpy.ScrCpyServer",
+        maximum_size_string,
     };
     return adb_execute(serial, cmd, sizeof(cmd) / sizeof(cmd[0]));
 }

app/src/server.h

@@ -4,5 +4,5 @@ process_t push_server(const char *serial);
 process_t enable_tunnel(const char *serial, Uint16 local_port);
 process_t disable_tunnel(const char *serial);
 
-process_t start_server(const char *serial);
+process_t start_server(const char *serial, Uint16 maximum_size);
 void stop_server(process_t server);