Use precise scrolling values

Since SDL 2.0.18, the amount scrolled horizontally or vertically is
exposed as a float (between 0 and 1). Forward a precise value to the
Android device when possible.

Refs <https://wiki.libsdl.org/SDL_MouseWheelEvent>
Fixes #3363 <https://github.com/Genymobile/scrcpy/issues/3363>
PR #3369 <https://github.com/Genymobile/scrcpy/pull/3369>

Signed-off-by: Romain Vimont <rom@rom1v.com>

app/src/adb/adb.c

@@ -401,6 +401,7 @@ sc_adb_list_devices(struct sc_intr *intr, unsigned flags,
 #define BUFSIZE 65536
     char *buf = malloc(BUFSIZE);
     if (!buf) {
+        LOG_OOM();
         return false;
     }
 
@@ -434,7 +435,6 @@ sc_adb_list_devices(struct sc_intr *intr, unsigned flags,
              "Please report an issue.");
         return false;
     }
-#undef BUFSIZE
 
     // It is parsed as a NUL-terminated string
     buf[r] = '\0';
@@ -713,95 +713,3 @@ sc_adb_get_device_ip(struct sc_intr *intr, const char *serial, unsigned flags) {
 
     return sc_adb_parse_device_ip(buf);
 }
-
-char *
-sc_adb_get_installed_apk_path(struct sc_intr *intr, const char *serial,
-                              unsigned flags) {
-    assert(serial);
-    const char *const argv[] =
-        SC_ADB_COMMAND("-s", serial, "shell", "pm", "list", "package", "-f",
-                       SC_ANDROID_PACKAGE);
-
-    sc_pipe pout;
-    sc_pid pid = sc_adb_execute_p(argv, flags, &pout);
-    if (pid == SC_PROCESS_NONE) {
-        LOGD("Could not execute \"pm list packages\"");
-        return NULL;
-    }
-
-    // "pm list packages -f <package>" output should contain only one line, so
-    // the output should be short
-    char buf[1024];
-    ssize_t r = sc_pipe_read_all_intr(intr, pid, pout, buf, sizeof(buf) - 1);
-    sc_pipe_close(pout);
-
-    bool ok = process_check_success_intr(intr, pid, "pm list packages", flags);
-    if (!ok) {
-        return NULL;
-    }
-
-    if (r == -1) {
-        return NULL;
-    }
-
-    assert((size_t) r < sizeof(buf));
-    if (r == sizeof(buf) - 1)  {
-        // The implementation assumes that the output of "pm list packages"
-        // fits in the buffer in a single pass
-        LOGW("Result of \"pm list package\" does not fit in 1Kb. "
-             "Please report an issue.");
-        return NULL;
-    }
-
-    // It is parsed as a NUL-terminated string
-    buf[r] = '\0';
-
-    return sc_adb_parse_installed_apk_path(buf);
-}
-
-char *
-sc_adb_get_installed_apk_version(struct sc_intr *intr, const char *serial,
-                                 unsigned flags) {
-    assert(serial);
-    const char *const argv[] =
-        SC_ADB_COMMAND("-s", serial, "shell", "dumpsys", "package",
-                       SC_ANDROID_PACKAGE);
-
-    sc_pipe pout;
-    sc_pid pid = sc_adb_execute_p(argv, flags, &pout);
-    if (pid == SC_PROCESS_NONE) {
-        LOGD("Could not execute \"dumpsys package\"");
-        return NULL;
-    }
-
-    // "dumpsys package" output can be huge (e.g. 16k), but versionName is at
-    // the beginning, typically in the first 1024 bytes (64k should be enough
-    // for the whole output anyway)
-#define BUFSIZE 65536
-    char *buf = malloc(BUFSIZE);
-    if (!buf) {
-        return false;
-    }
-    ssize_t r = sc_pipe_read_all_intr(intr, pid, pout, buf, BUFSIZE - 1);
-    sc_pipe_close(pout);
-
-    bool ok = process_check_success_intr(intr, pid, "dumpsys package", flags);
-    if (!ok) {
-        return NULL;
-    }
-
-    if (r == -1) {
-        return NULL;
-    }
-
-    assert((size_t) r < BUFSIZE);
-#undef BUFSIZE
-    // if r == sizeof(buf), then the output is truncated, but we don't care,
-    // versionName is at the beginning in practice, and is unlikely to be
-    // truncated at 64k
-
-    // It is parsed as a NUL-terminated string
-    buf[r] = '\0';
-
-    return sc_adb_parse_installed_apk_version(buf);
-}

app/src/adb/adb.h

@@ -15,8 +15,6 @@
 
 #define SC_ADB_SILENT (SC_ADB_NO_STDOUT | SC_ADB_NO_STDERR | SC_ADB_NO_LOGERR)
 
-#define SC_ANDROID_PACKAGE "com.genymobile.scrcpy"
-
 const char *
 sc_adb_get_executable(void);
 
@@ -116,18 +114,4 @@ sc_adb_getprop(struct sc_intr *intr, const char *serial, const char *prop,
 char *
 sc_adb_get_device_ip(struct sc_intr *intr, const char *serial, unsigned flags);
 
-/**
- * Return the path of the installed APK for com.genymobile.scrcpy (if any)
- */
-char *
-sc_adb_get_installed_apk_path(struct sc_intr *intr, const char *serial,
-                              unsigned flags);
-
-/**
- * Return the version of the installed APK for com.genymobile.scrcpy (if any)
- */
-char *
-sc_adb_get_installed_apk_version(struct sc_intr *intr, const char *serial,
-                                 unsigned flags);
-
 #endif

app/src/adb/adb_parser.c

@@ -225,62 +225,3 @@ sc_adb_parse_device_ip(char *str) {
 
     return NULL;
 }
-
-char *
-sc_adb_parse_installed_apk_path(char *str) {
-    // str is expected to look like:
-    // "package:/data/app/.../base.apk=com.genymobile.scrcpy"
-    //          ^^^^^^^^^^^^^^^^^^^^^^
-    // We want to extract the path (which may contain '=', even in practice)
-
-    if (strncmp(str, "package:", 8)) {
-        // Does not start with "package:"
-        return NULL;
-    }
-
-    char *s = str + 8;
-    size_t len = strcspn(s, " \r\n");
-    s[len] = '\0';
-
-    char *p = strrchr(s, '=');
-    if (!p) {
-        // No '=' found
-        return NULL;
-    }
-
-    // Truncate at the last '='
-    *p = '\0';
-
-    return strdup(s);
-}
-
-char *
-sc_adb_parse_installed_apk_version(const char *str) {
-    // str is the (beginning of the) output of `dumpsys package`
-    // We want to extract the version string from a line starting with 4 spaces
-    // then `versionName=` then the version string.
-
-#define VERSION_NAME_PREFIX "\n    versionName="
-    char *s = strstr(str, VERSION_NAME_PREFIX);
-    if (!s) {
-        // Not found
-        return NULL;
-    }
-
-    s+= sizeof(VERSION_NAME_PREFIX) - 1;
-
-    size_t len = strspn(s, "0123456789.");
-    if (!len) {
-        LOGW("Unexpected version name with no value");
-        return NULL;
-    }
-
-    char *version = malloc(len + 1);
-    if (!version) {
-        return NULL;
-    }
-
-    memcpy(version, s, len);
-    version[len] = '\0';
-    return version;
-}

app/src/adb/adb_parser.h

@@ -27,24 +27,4 @@ sc_adb_parse_devices(char *str, struct sc_vec_adb_devices *out_vec);
 char *
 sc_adb_parse_device_ip(char *str);
 
-/**
- * Parse the package path from the output of
- * `adb shell pm list packages -f <package>`
- *
- * The parameter must be a NUL-terminated string.
- *
- * Warning: this function modifies the buffer for optimization purposes.
- */
-char *
-sc_adb_parse_installed_apk_path(char *str);
-
-/**
- * Parse the package version from the output of
- * `adb shell dumpsys package <package>`
- *
- * The parameter must be a NUL-terminated string.
- */
-char *
-sc_adb_parse_installed_apk_version(const char *str);
-
 #endif

app/src/control_msg.c

@@ -115,12 +115,15 @@ sc_control_msg_serialize(const struct sc_control_msg *msg, unsigned char *buf) {
             return 28;
         case SC_CONTROL_MSG_TYPE_INJECT_SCROLL_EVENT:
             write_position(&buf[1], &msg->inject_scroll_event.position);
-            sc_write32be(&buf[13],
+            // map [-1, 1] to [0, 1], then to uint16
-                             (uint32_t) msg->inject_scroll_event.hscroll);
+            uint16_t hscroll =
-            sc_write32be(&buf[17],
+                to_fixed_point_16((msg->inject_scroll_event.hscroll + 1) / 2);
-                             (uint32_t) msg->inject_scroll_event.vscroll);
+            uint16_t vscroll =
-            sc_write32be(&buf[21], msg->inject_scroll_event.buttons);
+                to_fixed_point_16((msg->inject_scroll_event.vscroll + 1) / 2);
-            return 25;
+            sc_write16be(&buf[13], hscroll);
+            sc_write16be(&buf[15], vscroll);
+            sc_write32be(&buf[17], msg->inject_scroll_event.buttons);
+            return 21;
         case SC_CONTROL_MSG_TYPE_BACK_OR_SCREEN_ON:
             buf[1] = msg->inject_keycode.action;
             return 2;
@@ -191,8 +194,8 @@ sc_control_msg_log(const struct sc_control_msg *msg) {
             break;
         }
         case SC_CONTROL_MSG_TYPE_INJECT_SCROLL_EVENT:
-            LOG_CMSG("scroll position=%" PRIi32 ",%" PRIi32 " hscroll=%" PRIi32
+            LOG_CMSG("scroll position=%" PRIi32 ",%" PRIi32 " hscroll=%g"
-                         " vscroll=%" PRIi32 " buttons=%06lx",
+                         " vscroll=%g buttons=%06lx",
                      msg->inject_scroll_event.position.point.x,
                      msg->inject_scroll_event.position.point.y,
                      msg->inject_scroll_event.hscroll,

app/src/control_msg.h

@@ -68,8 +68,8 @@ struct sc_control_msg {
         } inject_touch_event;
         struct {
             struct sc_position position;
-            int32_t hscroll;
+            float hscroll;
-            int32_t vscroll;
+            float vscroll;
             enum android_motionevent_buttons buttons;
         } inject_scroll_event;
         struct {

app/src/demuxer.c

@@ -37,8 +37,8 @@ sc_demuxer_recv_packet(struct sc_demuxer *demuxer, AVPacket *packet) {
     // CK...... ........ ........ ........ ........ ........ ........ ........
     // ^^<------------------------------------------------------------------->
     // ||                                PTS
-    // | `- config packet
+    // | `- key frame
-    //  `-- key frame
+    //  `-- config packet
 
     uint8_t header[SC_PACKET_HEADER_SIZE];
     ssize_t r = net_recv_all(demuxer->socket, header, SC_PACKET_HEADER_SIZE);

app/src/input_events.h

@@ -358,8 +358,8 @@ struct sc_mouse_click_event {
 
 struct sc_mouse_scroll_event {
     struct sc_position position;
-    int32_t hscroll;
+    float hscroll;
-    int32_t vscroll;
+    float vscroll;
     uint8_t buttons_state; // bitwise-OR of sc_mouse_button values
 };
 

app/src/input_manager.c

@@ -747,8 +747,13 @@ sc_input_manager_process_mouse_wheel(struct sc_input_manager *im,
             .point = sc_screen_convert_window_to_frame_coords(im->screen,
                                                               mouse_x, mouse_y),
         },
-        .hscroll = event->x,
+#if SDL_VERSION_ATLEAST(2, 0, 18)
-        .vscroll = event->y,
+        .hscroll = CLAMP(event->preciseX, -1.0f, 1.0f),
+        .vscroll = CLAMP(event->preciseY, -1.0f, 1.0f),
+#else
+        .hscroll = CLAMP(event->x, -1, 1),
+        .vscroll = CLAMP(event->y, -1, 1),
+#endif
         .buttons_state =
             sc_mouse_buttons_state_from_sdl(buttons, im->forward_all_clicks),
     };

app/src/server.c

@@ -160,8 +160,6 @@ execute_server(struct sc_server *server,
     const char *serial = server->serial;
     assert(serial);
 
-    fprintf(stderr, "=== [%s]\n", sc_adb_get_installed_apk_version(&server->intr, serial, 0));
-
     const char *cmd[128];
     unsigned count = 0;
     cmd[count++] = sc_adb_get_executable();

app/src/usb/usb.c

@@ -23,6 +23,11 @@ read_string(libusb_device_handle *handle, uint8_t desc_index) {
 
     // When non-negative, 'result' contains the number of bytes written
     char *s = malloc(result + 1);
+    if (!s) {
+        LOG_OOM();
+        return NULL;
+    }
+
     memcpy(s, buffer, result);
     s[result] = '\0';
     return s;

app/tests/test_adb_parser.c

@@ -241,54 +241,6 @@ static void test_get_ip_truncated(void) {
     assert(!ip);
 }
 
-static void test_apk_path(void) {
-    char str[] = "package:/data/app/~~71mguyc6p-kNjQdNaNkToA==/com.genymobile."
-                 "scrcpy-l6fiqqUSU7Ok7QLg-rIyJA==/base.apk=com.genymobile."
-                 "scrcpy\n";
-
-    const char *expected = "/data/app/~~71mguyc6p-kNjQdNaNkToA==/com.genymobile"
-                           ".scrcpy-l6fiqqUSU7Ok7QLg-rIyJA==/base.apk";
-    char *path = sc_adb_parse_installed_apk_path(str);
-    assert(!strcmp(path, expected));
-    free(path);
-}
-
-static void test_apk_path_invalid(void) {
-    // Does not start with "package:"
-    char str[] = "garbage:/data/app/~~71mguyc6p-kNjQdNaNkToA==/com.genymobile."
-                 "scrcpy-l6fiqqUSU7Ok7QLg-rIyJA==/base.apk=com.genymobile."
-                 "scrcpy\n";
-
-    char *path = sc_adb_parse_installed_apk_path(str);
-    assert(!path);
-}
-
-static void test_apk_version(void) {
-    char str[] =
-        "Key Set Manager:\n"
-        "  [com.genymobile.scrcpy]\n"
-        "      Signing KeySets: 128\n"
-        "\n"
-        "Packages:\n"
-        "  Package [com.genymobile.scrcpy] (89abcdef):\n"
-        "    userId=12345\n"
-        "    pkg=Package{012345 com.genymobile.scrcpy}\n"
-        "    codePath=/data/app/~~abcdef==/com.genymobile.scrcpy-012345==\n"
-        "    resourcePath=/data/app/~~abcdef==/com.genymobile.scrcpy-013245==\n"
-        "    primaryCpuAbi=null\n"
-        "    secondaryCpuAbi=null\n"
-        "    versionCode=12400 minSdk=21 targetSdk=31\n"
-        "    versionName=1.24\n"
-        "    splits=[base]\n"
-        "    apkSigningVersion=2\n"
-        "    applicationInfo=ApplicationInfo{012345 com.genymobile.scrcpy}\n";
-
-    const char *expected = "1.24";
-    char *version = sc_adb_parse_installed_apk_version(str);
-    assert(!strcmp(version, expected));
-    free(version);
-}
-
 int main(int argc, char *argv[]) {
     (void) argc;
     (void) argv;
@@ -311,9 +263,5 @@ int main(int argc, char *argv[]) {
     test_get_ip_no_wlan_without_eol();
     test_get_ip_truncated();
 
-    test_apk_path();
-    test_apk_path_invalid();
-    test_apk_version();
-
     return 0;
 }

server/build.gradle

@@ -19,7 +19,6 @@ android {
 }
 
 dependencies {
-    implementation fileTree(dir: 'libs', include: ['*.jar'])
     testImplementation 'junit:junit:4.13.1'
 }
 

server/src/main/java/com/genymobile/scrcpy/ControlMessage.java

@@ -33,8 +33,8 @@ public final class ControlMessage {
     private long pointerId;
     private float pressure;
     private Position position;
-    private int hScroll;
+    private float hScroll;
-    private int vScroll;
+    private float vScroll;
     private int copyKey;
     private boolean paste;
     private int repeat;
@@ -71,7 +71,7 @@ public final class ControlMessage {
         return msg;
     }
 
-    public static ControlMessage createInjectScrollEvent(Position position, int hScroll, int vScroll, int buttons) {
+    public static ControlMessage createInjectScrollEvent(Position position, float hScroll, float vScroll, int buttons) {
         ControlMessage msg = new ControlMessage();
         msg.type = TYPE_INJECT_SCROLL_EVENT;
         msg.position = position;
@@ -156,11 +156,11 @@ public final class ControlMessage {
         return position;
     }
 
-    public int getHScroll() {
+    public float getHScroll() {
         return hScroll;
     }
 
-    public int getVScroll() {
+    public float getVScroll() {
         return vScroll;
     }
 

server/src/main/java/com/genymobile/scrcpy/ControlMessageReader.java

@@ -10,7 +10,7 @@ public class ControlMessageReader {
 
     static final int INJECT_KEYCODE_PAYLOAD_LENGTH = 13;
     static final int INJECT_TOUCH_EVENT_PAYLOAD_LENGTH = 27;
-    static final int INJECT_SCROLL_EVENT_PAYLOAD_LENGTH = 24;
+    static final int INJECT_SCROLL_EVENT_PAYLOAD_LENGTH = 20;
     static final int BACK_OR_SCREEN_ON_LENGTH = 1;
     static final int SET_SCREEN_POWER_MODE_PAYLOAD_LENGTH = 1;
     static final int GET_CLIPBOARD_LENGTH = 1;
@@ -139,10 +139,7 @@ public class ControlMessageReader {
         int action = toUnsigned(buffer.get());
         long pointerId = buffer.getLong();
         Position position = readPosition(buffer);
-        // 16 bits fixed-point
+        float pressure = fixedPointToFloat(buffer.getShort());
-        int pressureInt = toUnsigned(buffer.getShort());
-        // convert it to a float between 0 and 1 (0x1p16f is 2^16 as float)
-        float pressure = pressureInt == 0xffff ? 1f : (pressureInt / 0x1p16f);
         int buttons = buffer.getInt();
         return ControlMessage.createInjectTouchEvent(action, pointerId, position, pressure, buttons);
     }
@@ -152,8 +149,9 @@ public class ControlMessageReader {
             return null;
         }
         Position position = readPosition(buffer);
-        int hScroll = buffer.getInt();
+        // map from [0; 1] to [-1; 1]
-        int vScroll = buffer.getInt();
+        float hScroll = fixedPointToFloat(buffer.getShort());
+        float vScroll = fixedPointToFloat(buffer.getShort());
         int buttons = buffer.getInt();
         return ControlMessage.createInjectScrollEvent(position, hScroll, vScroll, buttons);
     }
@@ -210,4 +208,10 @@ public class ControlMessageReader {
     private static int toUnsigned(byte value) {
         return value & 0xff;
     }
+
+    private static float fixedPointToFloat(short value) {
+        int unsignedShort = toUnsigned(value);
+        // convert 16 bits fixed-point to a float between 0 and 1 (0x1p16f is 2^16 as float)
+        return unsignedShort == 0xffff ? 1f : (unsignedShort / 0x1p16f);
+    }
 }

server/src/main/java/com/genymobile/scrcpy/Controller.java

@@ -223,7 +223,7 @@ public class Controller {
         return device.injectEvent(event, Device.INJECT_MODE_ASYNC);
     }
 
-    private boolean injectScroll(Position position, int hScroll, int vScroll, int buttons) {
+    private boolean injectScroll(Position position, float hScroll, float vScroll, int buttons) {
         long now = SystemClock.uptimeMillis();
         Point point = device.getPhysicalPoint(position);
         if (point == null) {

server/src/test/java/com/genymobile/scrcpy/ControlMessageReaderTest.java

@@ -126,8 +126,8 @@ public class ControlMessageReaderTest {
         dos.writeInt(1026);
         dos.writeShort(1080);
         dos.writeShort(1920);
-        dos.writeInt(1);
+        dos.writeShort(0x8000);
-        dos.writeInt(-1);
+        dos.writeShort(0);
         dos.writeInt(1);
 
         byte[] packet = bos.toByteArray();
@@ -143,8 +143,8 @@ public class ControlMessageReaderTest {
         Assert.assertEquals(1026, event.getPosition().getPoint().getY());
         Assert.assertEquals(1080, event.getPosition().getScreenSize().getWidth());
         Assert.assertEquals(1920, event.getPosition().getScreenSize().getHeight());
-        Assert.assertEquals(1, event.getHScroll());
+        Assert.assertEquals(0f, event.getHScroll(), 0f);
-        Assert.assertEquals(-1, event.getVScroll());
+        Assert.assertEquals(-1f, event.getVScroll(), 0f);
         Assert.assertEquals(1, event.getButtons());
     }