Add an option to enable "show touches"

Add -t/--show-touches option to show physical touches while scrcpy is
running.

See <https://github.com/Genymobile/scrcpy/issues/96>.

README.md

@@ -247,6 +247,12 @@ If several devices are listed in `adb devices`, you must specify the _serial_:
 scrcpy -s 0123456789abcdef
 ```
 
+To show physical touches while scrcpy is running:
+
+```bash
+scrcpy -t
+```
+
 To run without installing:
 
 ```bash

app/src/command.c

@@ -4,10 +4,9 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "common.h"
 #include "log.h"
 
-#define ARRAY_LEN(a) (sizeof(a) / sizeof(a[0]))
-
 static const char *adb_command;
 
 static inline const char *get_adb_command() {

app/src/common.h

@@ -3,6 +3,7 @@
 
 #include <SDL2/SDL_stdinc.h>
 
+#define ARRAY_LEN(a) (sizeof(a) / sizeof(a[0]))
 #define MIN(X,Y) (X) < (Y) ? (X) : (Y)
 #define MAX(X,Y) (X) > (Y) ? (X) : (Y)
 

app/src/main.c

@@ -12,6 +12,7 @@ struct args {
     const char *serial;
     SDL_bool help;
     SDL_bool version;
+    SDL_bool show_touches;
     Uint16 port;
     Uint16 max_size;
     Uint32 bit_rate;
@@ -45,6 +46,10 @@ static void usage(const char *arg0) {
         "        The device serial number. Mandatory only if several devices\n"
         "        are connected to adb.\n"
         "\n"
+        "    -t, --show-touches\n"
+        "        Enable \"show touches\" on start, disable on quit.\n"
+        "        It only shows physical touches (not clicks from scrcpy).\n"
+        "\n"
         "    -v, --version\n"
         "        Print the version of scrcpy.\n"
         "\n"
@@ -188,11 +193,12 @@ static SDL_bool parse_args(struct args *args, int argc, char *argv[]) {
         {"max-size",     required_argument, NULL, 'm'},
         {"port",         required_argument, NULL, 'p'},
         {"serial",       required_argument, NULL, 's'},
+        {"show-touches", no_argument,       NULL, 't'},
         {"version",      no_argument,       NULL, 'v'},
         {NULL,           0,                 NULL, 0  },
     };
     int c;
-    while ((c = getopt_long(argc, argv, "b:hm:p:s:v", long_options, NULL)) != -1) {
+    while ((c = getopt_long(argc, argv, "b:hm:p:s:tv", long_options, NULL)) != -1) {
         switch (c) {
             case 'b':
                 if (!parse_bit_rate(optarg, &args->bit_rate)) {
@@ -215,6 +221,9 @@ static SDL_bool parse_args(struct args *args, int argc, char *argv[]) {
             case 's':
                 args->serial = optarg;
                 break;
+            case 't':
+                args->show_touches = SDL_TRUE;
+                break;
             case 'v':
                 args->version = SDL_TRUE;
                 break;
@@ -243,6 +252,7 @@ int main(int argc, char *argv[]) {
         .serial = NULL,
         .help = SDL_FALSE,
         .version = SDL_FALSE,
+        .show_touches = SDL_FALSE,
         .port = DEFAULT_LOCAL_PORT,
         .max_size = DEFAULT_MAX_SIZE,
         .bit_rate = DEFAULT_BIT_RATE,
@@ -276,6 +286,7 @@ int main(int argc, char *argv[]) {
         .port = args.port,
         .max_size = args.max_size,
         .bit_rate = args.bit_rate,
+        .show_touches = args.show_touches,
     };
     int res = scrcpy(&options) ? 0 : 1;
 

app/src/scrcpy.c

@@ -106,6 +106,15 @@ static void event_loop(void) {
     }
 }
 
+static SDL_bool set_show_touches_enabled(const char *serial, SDL_bool enabled) {
+    const char *value = enabled ? "1" : "0";
+    const char *const adb_cmd[] = {
+        "shell", "settings", "put", "system", "show_touches", value
+    };
+    process_t proc = adb_execute(serial, adb_cmd, ARRAY_LEN(adb_cmd));
+    return process_check_success(proc, "show_touches");
+}
+
 SDL_bool scrcpy(const struct scrcpy_options *options) {
     if (!server_start(&server, options->serial, options->port,
                       options->max_size, options->bit_rate)) {
@@ -173,9 +182,19 @@ SDL_bool scrcpy(const struct scrcpy_options *options) {
         goto finally_stop_and_join_controller;
     }
 
-    event_loop();
+    if (options->show_touches) {
+        LOGI("Enable show_touches");
+        set_show_touches_enabled(options->serial, SDL_TRUE);
+    }
 
+    event_loop();
     LOGD("quit...");
+
+    if (options->show_touches) {
+        LOGI("Disable show_touches");
+        set_show_touches_enabled(options->serial, SDL_FALSE);
+    }
+
     screen_destroy(&screen);
 finally_stop_and_join_controller:
     controller_stop(&controller);

app/src/scrcpy.h

@@ -8,6 +8,7 @@ struct scrcpy_options {
     Uint16 port;
     Uint16 max_size;
     Uint32 bit_rate;
+    SDL_bool show_touches;
 };
 
 SDL_bool scrcpy(const struct scrcpy_options *options);