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/clock.c

@@ -98,7 +98,7 @@ sc_clock_update(struct sc_clock *clock, sc_tick system, sc_tick stream) {
         sc_clock_estimate(clock, &clock->slope, &clock->offset);
 
 #ifndef SC_CLOCK_NDEBUG
-        LOGD("Clock estimation: %f * pts + %" PRItick,
+        LOGD("Clock estimation: %g * pts + %" PRItick,
              clock->slope, clock->offset);
 #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],
-                             (uint32_t) msg->inject_scroll_event.hscroll);
-            sc_write32be(&buf[17],
-                             (uint32_t) msg->inject_scroll_event.vscroll);
-            sc_write32be(&buf[21], msg->inject_scroll_event.buttons);
-            return 25;
+            // map [-1, 1] to [0, 1], then to uint16
+            uint16_t hscroll =
+                to_fixed_point_16((msg->inject_scroll_event.hscroll + 1) / 2);
+            uint16_t vscroll =
+                to_fixed_point_16((msg->inject_scroll_event.vscroll + 1) / 2);
+            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;
@@ -170,7 +173,7 @@ sc_control_msg_log(const struct sc_control_msg *msg) {
             if (id == POINTER_ID_MOUSE || id == POINTER_ID_VIRTUAL_FINGER) {
                 // string pointer id
                 LOG_CMSG("touch [id=%s] %-4s position=%" PRIi32 ",%" PRIi32
-                             " pressure=%f buttons=%06lx",
+                             " pressure=%g buttons=%06lx",
                          id == POINTER_ID_MOUSE ? "mouse" : "vfinger",
                          MOTIONEVENT_ACTION_LABEL(action),
                          msg->inject_touch_event.position.point.x,
@@ -180,7 +183,7 @@ sc_control_msg_log(const struct sc_control_msg *msg) {
             } else {
                 // numeric pointer id
                 LOG_CMSG("touch [id=%" PRIu64_ "] %-4s position=%" PRIi32 ",%"
-                             PRIi32 " pressure=%f buttons=%06lx",
+                             PRIi32 " pressure=%g buttons=%06lx",
                          id,
                          MOTIONEVENT_ACTION_LABEL(action),
                          msg->inject_touch_event.position.point.x,
@@ -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
-                         " vscroll=%" PRIi32 " buttons=%06lx",
+            LOG_CMSG("scroll position=%" PRIi32 ",%" PRIi32 " hscroll=%g"
+                         " 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;
-            int32_t vscroll;
+            float hscroll;
+            float vscroll;
             enum android_motionevent_buttons buttons;
         } inject_scroll_event;
         struct {

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;
-    int32_t vscroll;
+    float hscroll;
+    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,
-        .vscroll = event->y,
+#if SDL_VERSION_ATLEAST(2, 0, 18)
+        .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/util/net.c

@@ -3,10 +3,11 @@
 #include <assert.h>
 #include <errno.h>
 #include <stdio.h>
+#include <SDL2/SDL_platform.h>
 
 #include "log.h"
 
-#ifdef _WIN32
+#ifdef __WINDOWS__
 # include <ws2tcpip.h>
   typedef int socklen_t;
   typedef SOCKET sc_raw_socket;
@@ -28,7 +29,7 @@
 
 bool
 net_init(void) {
-#ifdef _WIN32
+#ifdef __WINDOWS__
     WSADATA wsa;
     int res = WSAStartup(MAKEWORD(2, 2), &wsa) < 0;
     if (res < 0) {
@@ -41,14 +42,14 @@ net_init(void) {
 
 void
 net_cleanup(void) {
-#ifdef _WIN32
+#ifdef __WINDOWS__
     WSACleanup();
 #endif
 }
 
 static inline sc_socket
 wrap(sc_raw_socket sock) {
-#ifdef _WIN32
+#ifdef __WINDOWS__
     if (sock == INVALID_SOCKET) {
         return SC_SOCKET_NONE;
     }
@@ -71,7 +72,7 @@ wrap(sc_raw_socket sock) {
 
 static inline sc_raw_socket
 unwrap(sc_socket socket) {
-#ifdef _WIN32
+#ifdef __WINDOWS__
     if (socket == SC_SOCKET_NONE) {
         return INVALID_SOCKET;
     }
@@ -159,8 +160,8 @@ net_connect(sc_socket socket, uint32_t addr, uint16_t port) {
 }
 
 bool
-net_listen(sc_socket server_socket, uint32_t addr, uint16_t port, int backlog) {
-    sc_raw_socket raw_sock = unwrap(server_socket);
+net_listen(sc_socket socket, uint32_t addr, uint16_t port, int backlog) {
+    sc_raw_socket raw_sock = unwrap(socket);
 
     int reuse = 1;
     if (setsockopt(raw_sock, SOL_SOCKET, SO_REUSEADDR, (const void *) &reuse,
@@ -247,7 +248,7 @@ net_interrupt(sc_socket socket) {
 
     sc_raw_socket raw_sock = unwrap(socket);
 
-#ifdef _WIN32
+#ifdef __WINDOWS__
     if (!atomic_flag_test_and_set(&socket->closed)) {
         return !closesocket(raw_sock);
     }
@@ -261,7 +262,7 @@ bool
 net_close(sc_socket socket) {
     sc_raw_socket raw_sock = unwrap(socket);
 
-#ifdef _WIN32
+#ifdef __WINDOWS__
     bool ret = true;
     if (!atomic_flag_test_and_set(&socket->closed)) {
         ret = !closesocket(raw_sock);

app/src/util/net.h

@@ -5,8 +5,9 @@
 
 #include <stdbool.h>
 #include <stdint.h>
+#include <SDL2/SDL_platform.h>
 
-#ifdef _WIN32
+#ifdef __WINDOWS__
 
 # include <winsock2.h>
 # include <stdatomic.h>
@@ -16,7 +17,7 @@
       atomic_flag closed;
   } *sc_socket;
 
-#else // not _WIN32
+#else // not __WINDOWS__
 
 # include <sys/socket.h>
 # define SC_SOCKET_NONE -1
@@ -39,7 +40,7 @@ bool
 net_connect(sc_socket socket, uint32_t addr, uint16_t port);
 
 bool
-net_listen(sc_socket server_socket, uint32_t addr, uint16_t port, int backlog);
+net_listen(sc_socket socket, uint32_t addr, uint16_t port, int backlog);
 
 sc_socket
 net_accept(sc_socket server_socket);

app/src/util/net_intr.c

@@ -15,14 +15,14 @@ net_connect_intr(struct sc_intr *intr, sc_socket socket, uint32_t addr,
 }
 
 bool
-net_listen_intr(struct sc_intr *intr, sc_socket server_socket, uint32_t addr,
+net_listen_intr(struct sc_intr *intr, sc_socket socket, uint32_t addr,
                 uint16_t port, int backlog) {
-    if (!sc_intr_set_socket(intr, server_socket)) {
+    if (!sc_intr_set_socket(intr, socket)) {
         // Already interrupted
         return false;
     }
 
-    bool ret = net_listen(server_socket, addr, port, backlog);
+    bool ret = net_listen(socket, addr, port, backlog);
 
     sc_intr_set_socket(intr, SC_SOCKET_NONE);
     return ret;

app/src/util/net_intr.h

@@ -11,7 +11,7 @@ net_connect_intr(struct sc_intr *intr, sc_socket socket, uint32_t addr,
                  uint16_t port);
 
 bool
-net_listen_intr(struct sc_intr *intr, sc_socket server_socket, uint32_t addr,
+net_listen_intr(struct sc_intr *intr, sc_socket socket, uint32_t addr,
                 uint16_t port, int backlog);
 
 sc_socket

server/meson.build

@@ -13,8 +13,8 @@ if prebuilt_server == ''
                   install_dir: 'share/scrcpy')
 else
     if not prebuilt_server.startswith('/')
-        # prebuilt server path is relative to the root scrcpy directory
-        prebuilt_server = '../' + prebuilt_server
+        # relative path needs some trick
+        prebuilt_server = meson.source_root() + '/' + prebuilt_server
     endif
     custom_target('scrcpy-server-prebuilt',
                   input: prebuilt_server,

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 int vScroll;
+    private float hScroll;
+    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
-        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);
+        float pressure = fixedPointToFloat(buffer.getShort());
         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();
-        int vScroll = buffer.getInt();
+        // map from [0; 1] to [-1; 1]
+        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/main/java/com/genymobile/scrcpy/wrappers/DisplayManager.java

@@ -3,10 +3,12 @@ package com.genymobile.scrcpy.wrappers;
 import com.genymobile.scrcpy.DisplayInfo;
 import com.genymobile.scrcpy.Size;
 
-public final class DisplayManager {
-    private final Object manager; // instance of hidden class android.hardware.display.DisplayManagerGlobal
+import android.os.IInterface;
 
-    public DisplayManager(Object manager) {
+public final class DisplayManager {
+    private final IInterface manager;
+
+    public DisplayManager(IInterface manager) {
         this.manager = manager;
     }
 

server/src/main/java/com/genymobile/scrcpy/wrappers/ServiceManager.java

@@ -50,14 +50,7 @@ public final class ServiceManager {
 
     public DisplayManager getDisplayManager() {
         if (displayManager == null) {
-            try {
-                Class<?> clazz = Class.forName("android.hardware.display.DisplayManagerGlobal");
-                Method getInstanceMethod = clazz.getDeclaredMethod("getInstance");
-                Object dmg = getInstanceMethod.invoke(null);
-                displayManager = new DisplayManager(dmg);
-            } catch (ClassNotFoundException | NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
-                throw new AssertionError(e);
-            }
+            displayManager = new DisplayManager(getService("display", "android.hardware.display.IDisplayManager"));
         }
         return displayManager;
     }

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.writeInt(-1);
+        dos.writeShort(0x8000);
+        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(-1, event.getVScroll());
+        Assert.assertEquals(0f, event.getHScroll(), 0f);
+        Assert.assertEquals(-1f, event.getVScroll(), 0f);
         Assert.assertEquals(1, event.getButtons());
     }