buttons 4 & 5

This will allow the mouse processor to handle relative motion easily.

app/meson.build

@@ -14,7 +14,6 @@ src = [
     'src/file_handler.c',
     'src/fps_counter.c',
     'src/frame_buffer.c',
-    'src/input_events.c',
     'src/input_manager.c',
     'src/keyboard_inject.c',
     'src/mouse_inject.c',
@@ -78,6 +77,7 @@ if aoa_hid_support
     src += [
         'src/aoa_hid.c',
         'src/hid_keyboard.c',
+        'src/hid_mouse.c',
     ]
 endif
 

app/src/common.h

@@ -7,6 +7,7 @@
 #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)
+#define CLAMP(V,X,Y) MIN( MAX((V),(X)), (Y) )
 
 #define container_of(ptr, type, member) \
     ((type *) (((char *) (ptr)) - offsetof(type, member)))

app/src/control_msg.c

@@ -119,7 +119,8 @@ control_msg_serialize(const struct control_msg *msg, unsigned char *buf) {
                              (uint32_t) msg->inject_scroll_event.hscroll);
             buffer_write32be(&buf[17],
                              (uint32_t) msg->inject_scroll_event.vscroll);
-            return 21;
+            buffer_write32be(&buf[21], msg->inject_scroll_event.buttons);
+            return 25;
         case CONTROL_MSG_TYPE_BACK_OR_SCREEN_ON:
             buf[1] = msg->inject_keycode.action;
             return 2;
@@ -192,11 +193,12 @@ control_msg_log(const struct control_msg *msg) {
         }
         case CONTROL_MSG_TYPE_INJECT_SCROLL_EVENT:
             LOG_CMSG("scroll position=%" PRIi32 ",%" PRIi32 " hscroll=%" PRIi32
-                         " vscroll=%" PRIi32,
+                         " vscroll=%" PRIi32 " buttons=%06lx",
                      msg->inject_scroll_event.position.point.x,
                      msg->inject_scroll_event.position.point.y,
                      msg->inject_scroll_event.hscroll,
-                     msg->inject_scroll_event.vscroll);
+                     msg->inject_scroll_event.vscroll,
+                     (long) msg->inject_scroll_event.buttons);
             break;
         case CONTROL_MSG_TYPE_BACK_OR_SCREEN_ON:
             LOG_CMSG("back-or-screen-on %s",

app/src/control_msg.h

@@ -70,6 +70,7 @@ struct control_msg {
             struct sc_position position;
             int32_t hscroll;
             int32_t vscroll;
+            enum android_motionevent_buttons buttons;
         } inject_scroll_event;
         struct {
             enum android_keyevent_action action; // action for the BACK key

app/src/hid_keyboard.c

@@ -387,15 +387,6 @@ sc_key_processor_process_key(struct sc_key_processor *kp,
     }
 }
 
-static void
-sc_key_processor_process_text(struct sc_key_processor *kp,
-                              const struct sc_text_event *event) {
-    (void) kp;
-    (void) event;
-
-    // Never forward text input via HID (all the keys are injected separately)
-}
-
 bool
 sc_hid_keyboard_init(struct sc_hid_keyboard *kb, struct sc_aoa *aoa) {
     kb->aoa = aoa;
@@ -415,7 +406,9 @@ sc_hid_keyboard_init(struct sc_hid_keyboard *kb, struct sc_aoa *aoa) {
 
     static const struct sc_key_processor_ops ops = {
         .process_key = sc_key_processor_process_key,
-        .process_text = sc_key_processor_process_text,
+        // Never forward text input via HID (all the keys are injected
+        // separately)
+        .process_text = NULL,
     };
 
     // Clipboard synchronization is requested over the control socket, while HID

app/src/hid_mouse.c

@@ -0,0 +1,265 @@
+#include "hid_mouse.h"
+
+#include <assert.h>
+
+#include "input_events.h"
+#include "util/log.h"
+
+/** Downcast mouse processor to hid_mouse */
+#define DOWNCAST(MP) container_of(MP, struct sc_hid_mouse, mouse_processor)
+
+#define HID_MOUSE_ACCESSORY_ID 2
+
+// 1 byte for buttons + padding, 1 byte for X position, 1 byte for Y position
+#define HID_MOUSE_EVENT_SIZE 4
+
+/**
+ * Mouse descriptor from the specification:
+ * <https://www.usb.org/sites/default/files/hid1_11.pdf>
+ *
+ * Appendix E (p71): §E.10 Report Descriptor (Mouse)
+ *
+ * The usage tags (like Wheel) are listed in "HID Usage Tables":
+ * <https://www.usb.org/sites/default/files/documents/hut1_12v2.pdf>
+ * §4 Generic Desktop Page (0x01) (p26)
+ */
+static const unsigned char mouse_report_desc[]  = {
+    // Usage Page (Generic Desktop)
+    0x05, 0x01,
+    // Usage (Mouse)
+    0x09, 0x02,
+
+    // Collection (Application)
+    0xA1, 0x01,
+
+    // Usage (Pointer)
+    0x09, 0x01,
+
+    // Collection (Physical)
+    0xA1, 0x00,
+
+    // Usage Page (Buttons)
+    0x05, 0x09,
+
+    // Usage Minimum (1)
+    0x19, 0x01,
+     // Usage Maximum (5)
+    0x29, 0x05,
+    // Logical Minimum (0)
+    0x15, 0x00,
+    // Logical Maximum (1)
+    0x25, 0x01,
+    // Report Count (5)
+    0x95, 0x05,
+    // Report Size (1)
+    0x75, 0x01,
+    // Input (Data, Variable, Absolute): 5 buttons bits
+    0x81, 0x02,
+
+    // Report Count (1)
+    0x95, 0x01,
+    // Report Size (3)
+    0x75, 0x03,
+    // Input (Constant): 3 bits padding
+    0x81, 0x01,
+
+    // Usage Page (Generic Desktop)
+    0x05, 0x01,
+    // Usage (X)
+    0x09, 0x30,
+    // Usage (Y)
+    0x09, 0x31,
+    // Usage (Wheel)
+    0x09, 0x38,
+    // Local Minimum (-127)
+    0x15, 0x81,
+    // Local Maximum (127)
+    0x25, 0x7F,
+    // Report Size (8)
+    0x75, 0x08,
+    // Report Count (3)
+    0x95, 0x03,
+    // Input (Data, Variable, Relative): 3 position bytes (X, Y, Wheel)
+    0x81, 0x06,
+
+    // End Collection
+    0xC0,
+
+    // End Collection
+    0xC0,
+};
+
+/**
+ * A mouse HID event is 3 bytes long:
+ *
+ *  - byte 0: buttons state
+ *  - byte 1: relative x motion (signed byte from -127 to 127)
+ *  - byte 2: relative y motion (signed byte from -127 to 127)
+ *
+ *                   7 6 5 4 3 2 1 0
+ *                  +---------------+
+ *         byte 0:  |0 0 0 . . . . .| buttons state
+ *                  +---------------+
+ *                         ^ ^ ^ ^ ^
+ *                         | | | | `- left button
+ *                         | | | `--- right button
+ *                         | | `----- middle button
+ *                         | `------- button 4
+ *                         `--------- button 5
+ *
+ *                  +---------------+
+ *         byte 1:  |. . . . . . . .| relative x motion
+ *                  +---------------+
+ *         byte 2:  |. . . . . . . .| relative y motion
+ *                  +---------------+
+ *         byte 3:  |. . . . . . . .| wheel motion (-1, 0 or 1)
+ *                  +---------------+
+ *
+ * As an example, here is the report for a motion of (x=5, y=-4) with left
+ * button pressed:
+ *
+ *                  +---------------+
+ *                  |0 0 0 0 0 0 0 1| left button pressed
+ *                  +---------------+
+ *                  |0 0 0 0 0 1 0 1| horizontal motion (x = 5)
+ *                  +---------------+
+ *                  |1 1 1 1 1 1 0 0| relative y motion (y = -4)
+ *                  +---------------+
+ *                  |0 0 0 0 0 0 0 0| wheel motion
+ *                  +---------------+
+ */
+
+static bool
+sc_hid_mouse_event_init(struct sc_hid_event *hid_event) {
+    unsigned char *buffer = calloc(1, HID_MOUSE_EVENT_SIZE);
+    if (!buffer) {
+        LOG_OOM();
+        return false;
+    }
+
+    sc_hid_event_init(hid_event, HID_MOUSE_ACCESSORY_ID, buffer,
+                      HID_MOUSE_EVENT_SIZE);
+    return true;
+}
+
+static unsigned char
+buttons_state_to_hid_buttons(uint8_t buttons_state) {
+    unsigned char c = 0;
+    if (buttons_state & SC_MOUSE_BUTTON_LEFT) {
+        c |= 1 << 0;
+    }
+    if (buttons_state & SC_MOUSE_BUTTON_RIGHT) {
+        c |= 1 << 1;
+    }
+    if (buttons_state & SC_MOUSE_BUTTON_MIDDLE) {
+        c |= 1 << 2;
+    }
+    if (buttons_state & SC_MOUSE_BUTTON_X1) {
+        c |= 1 << 3;
+    }
+    if (buttons_state & SC_MOUSE_BUTTON_X2) {
+        c |= 1 << 4;
+    }
+    return c;
+}
+
+static void
+sc_mouse_processor_process_mouse_motion(struct sc_mouse_processor *mp,
+                                    const struct sc_mouse_motion_event *event) {
+    struct sc_hid_mouse *mouse = DOWNCAST(mp);
+
+    struct sc_hid_event hid_event;
+    if (!sc_hid_mouse_event_init(&hid_event)) {
+        return;
+    }
+
+    unsigned char *buffer = hid_event.buffer;
+    buffer[0] = buttons_state_to_hid_buttons(event->buttons_state);
+    buffer[1] = CLAMP(event->xrel, -127, 127);
+    buffer[2] = CLAMP(event->yrel, -127, 127);
+    buffer[3] = 0; // wheel coordinates only used for scrolling
+
+    if (!sc_aoa_push_hid_event(mouse->aoa, &hid_event)) {
+        sc_hid_event_destroy(&hid_event);
+        LOGW("Could request HID event");
+    }
+}
+
+static void
+sc_mouse_processor_process_mouse_click(struct sc_mouse_processor *mp,
+                                   const struct sc_mouse_click_event *event) {
+    struct sc_hid_mouse *mouse = DOWNCAST(mp);
+
+    struct sc_hid_event hid_event;
+    if (!sc_hid_mouse_event_init(&hid_event)) {
+        return;
+    }
+
+    unsigned char *buffer = hid_event.buffer;
+    buffer[0] = buttons_state_to_hid_buttons(event->buttons_state);
+    buffer[1] = 0; // no x motion
+    buffer[2] = 0; // no y motion
+    buffer[3] = 0; // wheel coordinates only used for scrolling
+
+    if (!sc_aoa_push_hid_event(mouse->aoa, &hid_event)) {
+        sc_hid_event_destroy(&hid_event);
+        LOGW("Could request HID event");
+    }
+}
+
+static void
+sc_mouse_processor_process_mouse_scroll(struct sc_mouse_processor *mp,
+                                    const struct sc_mouse_scroll_event *event) {
+    struct sc_hid_mouse *mouse = DOWNCAST(mp);
+
+    struct sc_hid_event hid_event;
+    if (!sc_hid_mouse_event_init(&hid_event)) {
+        return;
+    }
+
+    unsigned char *buffer = hid_event.buffer;
+    buffer[0] = 0; // buttons state irrelevant (and unknown)
+    buffer[1] = 0; // no x motion
+    buffer[2] = 0; // no y motion
+    // In practice, vscroll is always -1, 0 or 1, but in theory other values
+    // are possible
+    buffer[3] = CLAMP(event->vscroll, -127, 127);
+    // Horizontal scrolling ignored
+
+    if (!sc_aoa_push_hid_event(mouse->aoa, &hid_event)) {
+        sc_hid_event_destroy(&hid_event);
+        LOGW("Could request HID event");
+    }
+}
+
+bool
+sc_hid_mouse_init(struct sc_hid_mouse *mouse, struct sc_aoa *aoa) {
+    mouse->aoa = aoa;
+
+    bool ok = sc_aoa_setup_hid(aoa, HID_MOUSE_ACCESSORY_ID, mouse_report_desc,
+                               ARRAY_LEN(mouse_report_desc));
+    if (!ok) {
+        LOGW("Register HID mouse failed");
+        return false;
+    }
+
+    static const struct sc_mouse_processor_ops ops = {
+        .process_mouse_motion = sc_mouse_processor_process_mouse_motion,
+        .process_mouse_click = sc_mouse_processor_process_mouse_click,
+        .process_mouse_scroll = sc_mouse_processor_process_mouse_scroll,
+        // Touch events not supported (coordinates are not relative)
+        .process_touch = NULL,
+    };
+
+    mouse->mouse_processor.ops = &ops;
+
+    return true;
+}
+
+void
+sc_hid_mouse_destroy(struct sc_hid_mouse *mouse) {
+    bool ok = sc_aoa_unregister_hid(mouse->aoa, HID_MOUSE_ACCESSORY_ID);
+    if (!ok) {
+        LOGW("Could not unregister HID");
+    }
+}

app/src/hid_mouse.h

@@ -0,0 +1,23 @@
+#ifndef HID_MOUSE_H
+#define HID_MOUSE_H
+
+#include "common.h"
+
+#include <stdbool.h>
+
+#include "aoa_hid.h"
+#include "trait/mouse_processor.h"
+
+struct sc_hid_mouse {
+    struct sc_mouse_processor mouse_processor; // mouse processor trait
+
+    struct sc_aoa *aoa;
+};
+
+bool
+sc_hid_mouse_init(struct sc_hid_mouse *mouse, struct sc_aoa *aoa);
+
+void
+sc_hid_mouse_destroy(struct sc_hid_mouse *mouse);
+
+#endif

app/src/input_events.c

@@ -1,76 +0,0 @@
-#include <input_events.h>
-
-static inline uint16_t
-sc_mods_state_from_sdl(uint16_t mods_state) {
-    return mods_state;
-}
-
-static inline enum sc_keycode
-sc_keycode_from_sdl(SDL_Keycode keycode) {
-    return (enum sc_keycode) keycode;
-}
-
-static inline enum sc_scancode
-sc_scancode_from_sdl(SDL_Scancode scancode) {
-    return (enum sc_scancode) scancode;
-}
-
-static inline enum sc_action
-sc_action_from_sdl_keyboard_type(uint32_t type) {
-    assert(type == SDL_KEYDOWN || type == SDL_KEYUP);
-    if (type == SDL_KEYDOWN) {
-        return SC_ACTION_DOWN;
-    }
-    return SC_ACTION_UP;
-}
-
-static inline enum sc_action
-sc_action_from_sdl_mousebutton_type(uint32_t type) {
-    assert(type == SDL_MOUSEBUTTONDOWN || type == SDL_MOUSEBUTTONUP);
-    if (type == SDL_MOUSEBUTTONDOWN) {
-        return SC_ACTION_DOWN;
-    }
-    return SC_ACTION_UP;
-}
-
-static inline enum sc_mouse_button
-sc_mouse_button_from_sdl(uint8_t button) {
-    if (button >= SDL_BUTTON_LEFT && button <= SDL_BUTTON_X2) {
-        // SC_MOUSE_BUTTON_* constants are initialized from SDL_BUTTON(index)
-        return SDL_BUTTON(button);
-    }
-
-    return SC_MOUSE_BUTTON_UNKNOWN;
-}
-
-static inline uint8_t
-sc_mouse_buttons_state_from_sdl(uint32_t buttons_state) {
-    assert(buttons_state < 0x100); // fits in uint8_t
-    return buttons_state;
-}
-
-void
-sc_key_event_from_sdl(struct sc_key_event *event,
-                      const SDL_KeyboardEvent *sdl) {
-    event->action = sc_action_from_sdl_keyboard_type(sdl->type);
-    event->keycode = sc_keycode_from_sdl(sdl->keysym.sym);
-    event->scancode = sc_scancode_from_sdl(sdl->keysym.scancode);
-    event->repeat = sdl->repeat;
-    event->mods_state = sc_mods_state_from_sdl(sdl->keysym.mod);
-}
-
-void
-sc_text_event_from_sdl(struct sc_text_event *event,
-                       const SDL_TextInputEvent *sdl) {
-    event->text = sdl->text;
-}
-
-void
-sc_mouse_click_event_from_sdl(struct sc_mouse_click_event *event,
-                              const SDL_MouseButtonEvent *sdl,
-                              const SDL_Window *window,
-                              struct sc_size screen_size) {
-    event->action = sc_action_from_sdl_mousebutton_type(sdl->type);
-    event->button = sc_mouse_button_from_sdl(sdl->button);
-    event->position.screen_size = screen_size;
-}

app/src/input_events.h

@@ -10,9 +10,37 @@
 
 #include "coords.h"
 
-/* The values are purposely the same as the SDL constants, so that the
+/* The representation of input events in scrcpy is very close to the SDL API,
+ * for simplicity.
+ *
+ * This scrcpy input events API is designed to be consumed by input event
+ * processors (sc_key_processor and sc_mouse_processor, see app/src/trait/).
+ *
+ * One major semantic difference between SDL input events and scrcpy input
+ * events is their frame of reference (for mouse and touch events): SDL events
+ * coordinates are expressed in SDL window coordinates (the visible UI), while
+ * scrcpy events are expressed in device frame coordinates.
+ *
+ * In particular, the window may be visually scaled or rotated (with --rotation
+ * or MOD+Left/Right), but this does not impact scrcpy input events (contrary
+ * to SDL input events). This allows to abstract these display details from the
+ * input event processors (and to make them independent from the "screen").
+ *
+ * For many enums below, the values are purposely the same as the SDL
+ * constants (though not all SDL values are represented), so that the
  * implementation to convert from the SDL version to the scrcpy version is
- * straightforward */
+ * straightforward.
+ *
+ * In practice, there are 3 levels of input events:
+ *  1. SDL input events (as received from SDL)
+ *  2. scrcpy input events (this API)
+ *  3. the key/mouse processors input events (Android API or HID events)
+ *
+ * An input event is first received (1), then (if accepted) converted to an
+ * scrcpy input event (2), then submitted to the relevant key/mouse processor,
+ * which (if accepted) is converted to an Android event (to be sent to the
+ * server) or to an HID event (to be sent over USB/AOA directly).
+ */
 
 enum sc_mod {
     SC_MOD_LSHIFT = KMOD_LSHIFT,
@@ -333,6 +361,7 @@ struct sc_mouse_scroll_event {
     struct sc_position position;
     int32_t hscroll;
     int32_t vscroll;
+    uint8_t buttons_state; // bitwise-OR of sc_mouse_button values
 };
 
 struct sc_mouse_motion_event {
@@ -342,32 +371,6 @@ struct sc_mouse_motion_event {
     uint8_t buttons_state; // bitwise-OR of sc_mouse_button values
 };
 
-//enum sc_mouse_event_type {
-//    SC_MOUSE_EVENT_TYPE_CLICK,
-//    SC_MOUSE_EVENT_TYPE_MOVE,
-//    SC_MOUSE_EVENT_TYPE_SCROLL,
-//};
-//
-//struct sc_mouse_event {
-//    enum sc_mouse_event_type type;
-//    struct sc_position position;
-//    uint8_t buttons_state; // bitwise-OR of sc_mouse_button values
-//    union {
-//        struct {
-//            enum sc_action action;
-//            enum sc_mouse_button button;
-//        } click;
-//        struct {
-//            int32_t xrel;
-//            int32_t yrel;
-//        } move;
-//        struct {
-//            int32_t h;
-//            int32_t v;
-//        } scroll;
-//    };
-//};
-
 struct sc_touch_event {
     struct sc_position position;
     enum sc_touch_action action;
@@ -375,30 +378,4 @@ struct sc_touch_event {
     float pressure;
 };
 
-
-//void
-//sc_key_event_from_sdl(struct sc_key_event *event, const SDL_KeyboardEvent *sdl);
-//
-//void
-//sc_text_event_from_sdl(struct sc_text_event *event,
-//                       const SDL_TextInputEvent *sdl);
-//
-//void
-//sc_mouse_click_event_from_sdl(struct sc_mouse_click_event *event,
-//                              const SDL_MouseButtonEvent *sdl,
-//                              const SDL_Window *window,
-//                              struct sc_size screen_size);
-//
-//void
-//sc_mouse_wheel_event_from_sdl(struct sc_mouse_wheel_event *event,
-//                              const SDL_MouseWheelEvent *sdl);
-//
-//void
-//sc_mouse_motion_event_from_sdl(struct sc_mouse_motion_event *event,
-//                               const SDL_MouseMotionEvent *sdl);
-//
-//void
-//sc_touch_event_from_sdl(struct sc_touch_event *event,
-//                        const SDL_TouchFingerEvent *sdl);
-
 #endif

app/src/input_manager.c

@@ -63,35 +63,20 @@ sc_mouse_button_from_sdl(uint8_t button) {
 }
 
 static inline uint8_t
-sc_mouse_buttons_state_from_sdl(uint32_t buttons_state) {
+sc_mouse_buttons_state_from_sdl(uint32_t buttons_state,
+                                bool forward_all_clicks) {
     assert(buttons_state < 0x100); // fits in uint8_t
-    return buttons_state;
-}
 
-//void
-//sc_key_event_from_sdl(struct sc_key_event *event,
-//                      const SDL_KeyboardEvent *sdl) {
-//    event->action = sc_action_from_sdl_keyboard_type(sdl->type);
-//    event->keycode = sc_keycode_from_sdl(sdl->keysym.sym);
-//    event->scancode = sc_scancode_from_sdl(sdl->keysym.scancode);
-//    event->repeat = sdl->repeat;
-//    event->mods_state = sc_mods_state_from_sdl(sdl->keysym.mod);
-//}
-//
-//void
-//sc_text_event_from_sdl(struct sc_text_event *event,
-//                       const SDL_TextInputEvent *sdl) {
-//    event->text = sdl->text;
-//}
-//
-//void
-//sc_mouse_click_event_from_sdl(struct sc_mouse_click_event *event,
-//                              const SDL_MouseButtonEvent *sdl,
-//                              struct sc_size screen_size) {
-//    event->action = sc_action_from_sdl_mousebutton_type(sdl->type);
-//    event->button = sc_mouse_button_from_sdl(sdl->button);
-//    event->position.screen_size = screen_size;
-//}
+    uint8_t mask = SC_MOUSE_BUTTON_LEFT;
+    if (forward_all_clicks) {
+        mask |= SC_MOUSE_BUTTON_RIGHT
+              | SC_MOUSE_BUTTON_MIDDLE
+              | SC_MOUSE_BUTTON_X1
+              | SC_MOUSE_BUTTON_X2;
+    }
+
+    return buttons_state & mask;
+}
 
 #define SC_SDL_SHORTCUT_MODS_MASK (KMOD_CTRL | KMOD_ALT | KMOD_GUI)
 
@@ -401,6 +386,11 @@ rotate_client_right(struct screen *screen) {
 static void
 input_manager_process_text_input(struct input_manager *im,
                                  const SDL_TextInputEvent *event) {
+    if (!im->kp->ops->process_text) {
+        // The key processor does not support text input
+        return;
+    }
+
     if (is_shortcut_mod(im, SDL_GetModState())) {
         // A shortcut must never generate text events
         return;
@@ -637,20 +627,22 @@ input_manager_process_key(struct input_manager *im,
         .mods_state = sc_mods_state_from_sdl(event->keysym.mod),
     };
 
+    assert(im->kp->ops->process_key);
     im->kp->ops->process_key(im->kp, &evt, ack_to_wait);
 }
 
 static void
 input_manager_process_mouse_motion(struct input_manager *im,
                                    const SDL_MouseMotionEvent *event) {
+
     uint32_t mask = SDL_BUTTON_LMASK;
     if (im->forward_all_clicks) {
         mask |= SDL_BUTTON_MMASK | SDL_BUTTON_RMASK;
     }
-    if (!(event->state & mask)) {
-        // do not send motion events when no click is pressed
-        return;
-    }
+    //if (!(event->state & mask)) {
+    //    // do not send motion events when no click is pressed
+    //    return;
+    //}
     if (event->which == SDL_TOUCH_MOUSEID) {
         // simulated from touch events, so it's a duplicate
         return;
@@ -664,10 +656,13 @@ input_manager_process_mouse_motion(struct input_manager *im,
         },
         .xrel = event->xrel,
         .yrel = event->yrel,
-        .buttons_state = sc_mouse_buttons_state_from_sdl(event->state),
+        .buttons_state =
+            sc_mouse_buttons_state_from_sdl(event->state,
+                                            im->forward_all_clicks),
     };
 
-    im->mp->ops->process_mouse_motion(im->mp, event);
+    assert(im->mp->ops->process_mouse_motion);
+    im->mp->ops->process_mouse_motion(im->mp, &evt);
 
     if (im->vfinger_down) {
         struct sc_point mouse =
@@ -681,6 +676,11 @@ input_manager_process_mouse_motion(struct input_manager *im,
 static void
 input_manager_process_touch(struct input_manager *im,
                             const SDL_TouchFingerEvent *event) {
+    if (!im->mp->ops->process_touch) {
+        // The mouse processor does not support touch events
+        return;
+    }
+
     int dw;
     int dh;
     SDL_GL_GetDrawableSize(im->screen->window, &dw, &dh);
@@ -699,7 +699,7 @@ input_manager_process_touch(struct input_manager *im,
         .pressure = event->pressure,
     };
 
-    im->mp->ops->process_touch(im->mp, event);
+    im->mp->ops->process_touch(im->mp, &evt);
 }
 
 static void
@@ -769,10 +769,19 @@ input_manager_process_mouse_button(struct input_manager *im,
         },
         .action = sc_action_from_sdl_mousebutton_type(event->type),
         .button = sc_mouse_button_from_sdl(event->button),
-        .buttons_state = sc_mouse_buttons_state_from_sdl(sdl_buttons_state),
+        .buttons_state =
+            sc_mouse_buttons_state_from_sdl(sdl_buttons_state,
+                                            im->forward_all_clicks),
     };
 
-    im->mp->ops->process_mouse_button(im->mp, event);
+    assert(im->mp->ops->process_mouse_click);
+    im->mp->ops->process_mouse_click(im->mp, &evt);
+
+    if (im->mp->relative_mode) {
+        assert(!im->vfinger_down); // vfinger must not be used in relative mode
+        // No pinch-to-zoom simulation
+        return;
+    }
 
     // Pinch-to-zoom simulation.
     //
@@ -803,10 +812,15 @@ input_manager_process_mouse_button(struct input_manager *im,
 static void
 input_manager_process_mouse_wheel(struct input_manager *im,
                                   const SDL_MouseWheelEvent *event) {
+    if (!im->mp->ops->process_mouse_scroll) {
+        // The mouse processor does not support scroll events
+        return;
+    }
+
     // mouse_x and mouse_y are expressed in pixels relative to the window
     int mouse_x;
     int mouse_y;
-    SDL_GetMouseState(&mouse_x, &mouse_y);
+    uint32_t buttons = SDL_GetMouseState(&mouse_x, &mouse_y);
 
     struct sc_mouse_scroll_event evt = {
         .position = {
@@ -816,9 +830,11 @@ input_manager_process_mouse_wheel(struct input_manager *im,
         },
         .hscroll = event->x,
         .vscroll = event->y,
+        .buttons_state =
+            sc_mouse_buttons_state_from_sdl(buttons, im->forward_all_clicks),
     };
 
-    im->mp->ops->process_mouse_wheel(im->mp, event);
+    im->mp->ops->process_mouse_scroll(im->mp, &evt);
 }
 
 bool

app/src/keyboard_inject.c

@@ -12,20 +12,13 @@
 /** Downcast key processor to sc_keyboard_inject */
 #define DOWNCAST(KP) container_of(KP, struct sc_keyboard_inject, key_processor)
 
-static bool
-convert_keycode_action(enum sc_action from, enum android_keyevent_action *to) {
-    static const struct sc_intmap_entry actions[] = {
-        {SC_ACTION_DOWN, AKEY_EVENT_ACTION_DOWN},
-        {SC_ACTION_UP,   AKEY_EVENT_ACTION_UP},
-    };
-
-    const struct sc_intmap_entry *entry = SC_INTMAP_FIND_ENTRY(actions, from);
-    if (entry) {
-        *to = entry->value;
-        return true;
+static enum android_keyevent_action
+convert_keycode_action(enum sc_action action) {
+    if (action == SC_ACTION_DOWN) {
+        return AKEY_EVENT_ACTION_DOWN;
     }
-
-    return false;
+    assert(action == SC_ACTION_UP);
+    return AKEY_EVENT_ACTION_UP;
 }
 
 static bool
@@ -257,15 +250,12 @@ convert_input_key(const struct sc_key_event *event, struct control_msg *msg,
                   enum sc_key_inject_mode key_inject_mode, uint32_t repeat) {
     msg->type = CONTROL_MSG_TYPE_INJECT_KEYCODE;
 
-    if (!convert_keycode_action(event->action, &msg->inject_keycode.action)) {
-        return false;
-    }
-
     if (!convert_keycode(event->keycode, &msg->inject_keycode.keycode,
                          event->mods_state, key_inject_mode)) {
         return false;
     }
 
+    msg->inject_keycode.action = convert_keycode_action(event->action);
     msg->inject_keycode.repeat = repeat;
     msg->inject_keycode.metastate = convert_meta_state(event->mods_state);
 

app/src/mouse_inject.c

@@ -1,11 +1,11 @@
 #include "mouse_inject.h"
 
 #include <assert.h>
-#include <SDL2/SDL_events.h>
 
 #include "android/input.h"
 #include "control_msg.h"
 #include "controller.h"
+#include "input_events.h"
 #include "util/intmap.h"
 #include "util/log.h"
 
@@ -15,210 +15,142 @@
 static enum android_motionevent_buttons
 convert_mouse_buttons(uint32_t state) {
     enum android_motionevent_buttons buttons = 0;
-    if (state & SDL_BUTTON_LMASK) {
+    if (state & SC_MOUSE_BUTTON_LEFT) {
         buttons |= AMOTION_EVENT_BUTTON_PRIMARY;
     }
-    if (state & SDL_BUTTON_RMASK) {
+    if (state & SC_MOUSE_BUTTON_RIGHT) {
         buttons |= AMOTION_EVENT_BUTTON_SECONDARY;
     }
-    if (state & SDL_BUTTON_MMASK) {
+    if (state & SC_MOUSE_BUTTON_MIDDLE) {
         buttons |= AMOTION_EVENT_BUTTON_TERTIARY;
     }
-    if (state & SDL_BUTTON_X1MASK) {
+    if (state & SC_MOUSE_BUTTON_X1) {
         buttons |= AMOTION_EVENT_BUTTON_BACK;
     }
-    if (state & SDL_BUTTON_X2MASK) {
+    if (state & SC_MOUSE_BUTTON_X2) {
         buttons |= AMOTION_EVENT_BUTTON_FORWARD;
     }
     return buttons;
 }
 
-static bool
-convert_mouse_action(SDL_EventType from, enum android_motionevent_action *to) {
-    static const struct sc_intmap_entry actions[] = {
-        {SDL_MOUSEBUTTONDOWN, AMOTION_EVENT_ACTION_DOWN},
-        {SDL_MOUSEBUTTONUP,   AMOTION_EVENT_ACTION_UP},
-    };
-
-    const struct sc_intmap_entry *entry = SC_INTMAP_FIND_ENTRY(actions, from);
-    if (entry) {
-        *to = entry->value;
-        return true;
+static enum android_motionevent_action
+convert_mouse_action(enum sc_action action) {
+    if (action == SC_ACTION_DOWN) {
+        return AMOTION_EVENT_ACTION_DOWN;
     }
-
-    return false;
+    assert(action == SC_ACTION_UP);
+    return AMOTION_EVENT_ACTION_UP;
 }
 
-static bool
-convert_touch_action(SDL_EventType from, enum android_motionevent_action *to) {
-    static const struct sc_intmap_entry actions[] = {
-        {SDL_FINGERMOTION, AMOTION_EVENT_ACTION_MOVE},
-        {SDL_FINGERDOWN,   AMOTION_EVENT_ACTION_DOWN},
-        {SDL_FINGERUP,     AMOTION_EVENT_ACTION_UP},
-    };
-
-    const struct sc_intmap_entry *entry = SC_INTMAP_FIND_ENTRY(actions, from);
-    if (entry) {
-        *to = entry->value;
-        return true;
+static enum android_motionevent_action
+convert_touch_action(enum sc_touch_action action) {
+    switch (action) {
+        case SC_TOUCH_ACTION_MOVE:
+            return AMOTION_EVENT_ACTION_MOVE;
+        case SC_TOUCH_ACTION_DOWN:
+            return AMOTION_EVENT_ACTION_DOWN;
+        default:
+            assert(action == SC_TOUCH_ACTION_UP);
+            return AMOTION_EVENT_ACTION_UP;
     }
-
-    return false;
-}
-
-static bool
-convert_mouse_motion(const SDL_MouseMotionEvent *from, struct screen *screen,
-                     struct control_msg *to) {
-    to->type = CONTROL_MSG_TYPE_INJECT_TOUCH_EVENT;
-    to->inject_touch_event.action = AMOTION_EVENT_ACTION_MOVE;
-    to->inject_touch_event.pointer_id = POINTER_ID_MOUSE;
-    to->inject_touch_event.position.screen_size = screen->frame_size;
-    to->inject_touch_event.position.point =
-        screen_convert_window_to_frame_coords(screen, from->x, from->y);
-    to->inject_touch_event.pressure = 1.f;
-    to->inject_touch_event.buttons = convert_mouse_buttons(from->state);
-
-    return true;
-}
-
-static bool
-convert_touch(const SDL_TouchFingerEvent *from, struct screen *screen,
-              struct control_msg *to) {
-    to->type = CONTROL_MSG_TYPE_INJECT_TOUCH_EVENT;
-
-    if (!convert_touch_action(from->type, &to->inject_touch_event.action)) {
-        return false;
-    }
-
-    to->inject_touch_event.pointer_id = from->fingerId;
-    to->inject_touch_event.position.screen_size = screen->frame_size;
-
-    int dw;
-    int dh;
-    SDL_GL_GetDrawableSize(screen->window, &dw, &dh);
-
-    // SDL touch event coordinates are normalized in the range [0; 1]
-    int32_t x = from->x * dw;
-    int32_t y = from->y * dh;
-    to->inject_touch_event.position.point =
-        screen_convert_drawable_to_frame_coords(screen, x, y);
-
-    to->inject_touch_event.pressure = from->pressure;
-    to->inject_touch_event.buttons = 0;
-    return true;
-}
-
-static bool
-convert_mouse_button(const SDL_MouseButtonEvent *from, struct screen *screen,
-                     struct control_msg *to) {
-    to->type = CONTROL_MSG_TYPE_INJECT_TOUCH_EVENT;
-
-    if (!convert_mouse_action(from->type, &to->inject_touch_event.action)) {
-        return false;
-    }
-
-    to->inject_touch_event.pointer_id = POINTER_ID_MOUSE;
-    to->inject_touch_event.position.screen_size = screen->frame_size;
-    to->inject_touch_event.position.point =
-        screen_convert_window_to_frame_coords(screen, from->x, from->y);
-    to->inject_touch_event.pressure =
-        from->type == SDL_MOUSEBUTTONDOWN ? 1.f : 0.f;
-    to->inject_touch_event.buttons =
-        convert_mouse_buttons(SDL_BUTTON(from->button));
-
-    return true;
-}
-
-static bool
-convert_mouse_wheel(const SDL_MouseWheelEvent *from, struct screen *screen,
-                    struct control_msg *to) {
-
-    // mouse_x and mouse_y are expressed in pixels relative to the window
-    int mouse_x;
-    int mouse_y;
-    SDL_GetMouseState(&mouse_x, &mouse_y);
-
-    struct sc_position position = {
-        .screen_size = screen->frame_size,
-        .point = screen_convert_window_to_frame_coords(screen,
-                                                       mouse_x, mouse_y),
-    };
-
-    to->type = CONTROL_MSG_TYPE_INJECT_SCROLL_EVENT;
-
-    to->inject_scroll_event.position = position;
-    to->inject_scroll_event.hscroll = from->x;
-    to->inject_scroll_event.vscroll = from->y;
-
-    return true;
 }
 
 static void
 sc_mouse_processor_process_mouse_motion(struct sc_mouse_processor *mp,
-                                        const SDL_MouseMotionEvent *event) {
+                                    const struct sc_mouse_motion_event *event) {
     struct sc_mouse_inject *mi = DOWNCAST(mp);
 
-    struct control_msg msg;
-    if (!convert_mouse_motion(event, mi->screen, &msg)) {
-        return;
-    }
+    struct control_msg msg = {
+        .type = CONTROL_MSG_TYPE_INJECT_TOUCH_EVENT,
+        .inject_touch_event = {
+            .action = AMOTION_EVENT_ACTION_MOVE,
+            .pointer_id = POINTER_ID_MOUSE,
+            .position = event->position,
+            .pressure = 1.f,
+            .buttons = convert_mouse_buttons(event->buttons_state),
+        },
+    };
 
     if (!controller_push_msg(mi->controller, &msg)) {
         LOGW("Could not request 'inject mouse motion event'");
     }
 }
 
+static void
+sc_mouse_processor_process_mouse_click(struct sc_mouse_processor *mp,
+                                    const struct sc_mouse_click_event *event) {
+    struct sc_mouse_inject *mi = DOWNCAST(mp);
+
+    struct control_msg msg = {
+        .type = CONTROL_MSG_TYPE_INJECT_TOUCH_EVENT,
+        .inject_touch_event = {
+            .action = convert_mouse_action(event->action),
+            .pointer_id = POINTER_ID_MOUSE,
+            .position = event->position,
+            .pressure = event->action == SC_ACTION_DOWN ? 1.f : 0.f,
+            .buttons = convert_mouse_buttons(event->buttons_state),
+        },
+    };
+
+    if (!controller_push_msg(mi->controller, &msg)) {
+        LOGW("Could not request 'inject mouse click event'");
+    }
+}
+
+static void
+sc_mouse_processor_process_mouse_scroll(struct sc_mouse_processor *mp,
+                                   const struct sc_mouse_scroll_event *event) {
+    struct sc_mouse_inject *mi = DOWNCAST(mp);
+
+    struct control_msg msg = {
+        .type = CONTROL_MSG_TYPE_INJECT_SCROLL_EVENT,
+        .inject_scroll_event = {
+            .position = event->position,
+            .hscroll = event->hscroll,
+            .vscroll = event->vscroll,
+            .buttons = convert_mouse_buttons(event->buttons_state),
+        },
+    };
+
+    if (!controller_push_msg(mi->controller, &msg)) {
+        LOGW("Could not request 'inject mouse scroll event'");
+    }
+}
+
 static void
 sc_mouse_processor_process_touch(struct sc_mouse_processor *mp,
-                                 const SDL_TouchFingerEvent *event) {
+                                 const struct sc_touch_event *event) {
     struct sc_mouse_inject *mi = DOWNCAST(mp);
 
-    struct control_msg msg;
-    if (convert_touch(event, mi->screen, &msg)) {
-        if (!controller_push_msg(mi->controller, &msg)) {
-            LOGW("Could not request 'inject touch event'");
-        }
-    }
-}
+    struct control_msg msg = {
+        .type = CONTROL_MSG_TYPE_INJECT_TOUCH_EVENT,
+        .inject_touch_event = {
+            .action = convert_touch_action(event->action),
+            .pointer_id = event->pointer_id,
+            .position = event->position,
+            .pressure = event->pressure,
+            .buttons = 0,
+        },
+    };
 
-static void
-sc_mouse_processor_process_mouse_button(struct sc_mouse_processor *mp,
-                                        const SDL_MouseButtonEvent *event) {
-    struct sc_mouse_inject *mi = DOWNCAST(mp);
-
-    struct control_msg msg;
-    if (convert_mouse_button(event, mi->screen, &msg)) {
-        if (!controller_push_msg(mi->controller, &msg)) {
-            LOGW("Could not request 'inject mouse button event'");
-        }
-    }
-}
-
-static void
-sc_mouse_processor_process_mouse_wheel(struct sc_mouse_processor *mp,
-                                       const SDL_MouseWheelEvent *event) {
-    struct sc_mouse_inject *mi = DOWNCAST(mp);
-
-    struct control_msg msg;
-    if (convert_mouse_wheel(event, mi->screen, &msg)) {
-        if (!controller_push_msg(mi->controller, &msg)) {
-            LOGW("Could not request 'inject mouse wheel event'");
-        }
+    if (!controller_push_msg(mi->controller, &msg)) {
+        LOGW("Could not request 'inject touch event'");
     }
 }
 
 void
-sc_mouse_inject_init(struct sc_mouse_inject *mi, struct controller *controller,
-                     struct screen *screen) {
+sc_mouse_inject_init(struct sc_mouse_inject *mi,
+                     struct controller *controller) {
     mi->controller = controller;
-    mi->screen = screen;
 
     static const struct sc_mouse_processor_ops ops = {
         .process_mouse_motion = sc_mouse_processor_process_mouse_motion,
+        .process_mouse_click = sc_mouse_processor_process_mouse_click,
+        .process_mouse_scroll = sc_mouse_processor_process_mouse_scroll,
         .process_touch = sc_mouse_processor_process_touch,
-        .process_mouse_button = sc_mouse_processor_process_mouse_button,
-        .process_mouse_wheel = sc_mouse_processor_process_mouse_wheel,
     };
 
     mi->mouse_processor.ops = &ops;
+
+    mi->mouse_processor.relative_mode = false;
 }

app/src/mouse_inject.h

@@ -13,11 +13,9 @@ struct sc_mouse_inject {
     struct sc_mouse_processor mouse_processor; // mouse processor trait
 
     struct controller *controller;
-    struct screen *screen;
 };
 
 void
-sc_mouse_inject_init(struct sc_mouse_inject *mi, struct controller *controller,
-                     struct screen *screen);
+sc_mouse_inject_init(struct sc_mouse_inject *mi, struct controller *controller);
 
 #endif

app/src/scrcpy.c

@@ -20,6 +20,7 @@
 #include "input_manager.h"
 #ifdef HAVE_AOA_HID
 # include "hid_keyboard.h"
+# include "hid_mouse.h"
 #endif
 #include "keyboard_inject.h"
 #include "mouse_inject.h"
@@ -56,7 +57,12 @@ struct scrcpy {
         struct sc_hid_keyboard keyboard_hid;
 #endif
     };
-    struct sc_mouse_inject mouse_inject;
+    union {
+        struct sc_mouse_inject mouse_inject;
+#ifdef HAVE_AOA_HID
+        struct sc_hid_mouse mouse_hid;
+#endif
+    };
     struct input_manager input_manager;
 };
 
@@ -581,8 +587,9 @@ aoa_hid_end:
             kp = &s->keyboard_inject.key_processor;
         }
 
-        sc_mouse_inject_init(&s->mouse_inject, &s->controller, &s->screen);
-        mp = &s->mouse_inject.mouse_processor;
+        //sc_mouse_inject_init(&s->mouse_inject, &s->controller);
+        sc_hid_mouse_init(&s->mouse_hid, &s->aoa);
+        mp = &s->mouse_hid.mouse_processor;
     }
 
     input_manager_init(&s->input_manager, &s->controller, &s->screen, kp, mp,

app/src/screen.c

@@ -485,6 +485,10 @@ screen_init(struct screen *screen, const struct screen_params *params) {
     SDL_AddEventWatch(event_watcher, screen);
 #endif
 
+    if (SDL_SetRelativeMouseMode(true)) {
+        LOGE("Could not set relative mouse mode: %s", SDL_GetError());
+    }
+
     static const struct sc_frame_sink_ops ops = {
         .open = screen_frame_sink_open,
         .close = screen_frame_sink_close,

app/src/trait/key_processor.h

@@ -29,17 +29,24 @@ struct sc_key_processor {
 struct sc_key_processor_ops {
 
     /**
-     * Process the keyboard event
+     * Process a keyboard event
      *
      * The `sequence` number (if different from `SC_SEQUENCE_INVALID`) indicates
      * the acknowledgement number to wait for before injecting this event.
      * This allows to ensure that the device clipboard is set before injecting
      * Ctrl+v on the device.
+     *
+     * This function is mandatory.
      */
     void
     (*process_key)(struct sc_key_processor *kp,
                    const struct sc_key_event *event, uint64_t ack_to_wait);
 
+    /**
+     * Process an input text
+     *
+     * This function is optional.
+     */
     void
     (*process_text)(struct sc_key_processor *kp,
                     const struct sc_text_event *event);

app/src/trait/mouse_processor.h

@@ -6,7 +6,7 @@
 #include <assert.h>
 #include <stdbool.h>
 
-#include <SDL2/SDL_events.h>
+#include "input_events.h"
 
 /**
  * Mouse processor trait.
@@ -16,24 +16,51 @@
  */
 struct sc_mouse_processor {
     const struct sc_mouse_processor_ops *ops;
+
+    /**
+     * If set, the mouse processor works in relative mode (the absolute
+     * position is irrelevant). In particular, it indicates that the mouse
+     * pointer must be "captured" by the UI.
+     */
+    bool relative_mode;
 };
 
 struct sc_mouse_processor_ops {
+    /**
+     * Process a mouse motion event
+     *
+     * This function is mandatory.
+     */
     void
     (*process_mouse_motion)(struct sc_mouse_processor *mp,
-                            const SDL_MouseMotionEvent *event);
+                            const struct sc_mouse_motion_event *event);
 
+    /**
+     * Process a mouse click event
+     *
+     * This function is mandatory.
+     */
+    void
+    (*process_mouse_click)(struct sc_mouse_processor *mp,
+                           const struct sc_mouse_click_event *event);
+
+    /**
+     * Process a mouse scroll event
+     *
+     * This function is optional.
+     */
+    void
+    (*process_mouse_scroll)(struct sc_mouse_processor *mp,
+                            const struct sc_mouse_scroll_event *event);
+
+    /**
+     * Process a touch event
+     *
+     * This function is optional.
+     */
     void
     (*process_touch)(struct sc_mouse_processor *mp,
-                     const SDL_TouchFingerEvent *event);
-
-    void
-    (*process_mouse_button)(struct sc_mouse_processor *mp,
-                            const SDL_MouseButtonEvent *event);
-
-    void
-    (*process_mouse_wheel)(struct sc_mouse_processor *mp,
-                           const SDL_MouseWheelEvent *event);
+                     const struct sc_touch_event *event);
 };
 
 #endif

app/tests/test_adb_parser.c

@@ -11,6 +11,7 @@ static void test_get_ip_single_line() {
     char *ip = sc_adb_parse_device_ip_from_output(ip_route, sizeof(ip_route));
     assert(ip);
     assert(!strcmp(ip, "192.168.12.34"));
+    free(ip);
 }
 
 static void test_get_ip_single_line_without_eol() {
@@ -20,6 +21,7 @@ static void test_get_ip_single_line_without_eol() {
     char *ip = sc_adb_parse_device_ip_from_output(ip_route, sizeof(ip_route));
     assert(ip);
     assert(!strcmp(ip, "192.168.12.34"));
+    free(ip);
 }
 
 static void test_get_ip_single_line_with_trailing_space() {
@@ -29,6 +31,7 @@ static void test_get_ip_single_line_with_trailing_space() {
     char *ip = sc_adb_parse_device_ip_from_output(ip_route, sizeof(ip_route));
     assert(ip);
     assert(!strcmp(ip, "192.168.12.34"));
+    free(ip);
 }
 
 static void test_get_ip_multiline_first_ok() {
@@ -40,6 +43,7 @@ static void test_get_ip_multiline_first_ok() {
     char *ip = sc_adb_parse_device_ip_from_output(ip_route, sizeof(ip_route));
     assert(ip);
     assert(!strcmp(ip, "192.168.1.2"));
+    free(ip);
 }
 
 static void test_get_ip_multiline_second_ok() {
@@ -51,6 +55,7 @@ static void test_get_ip_multiline_second_ok() {
     char *ip = sc_adb_parse_device_ip_from_output(ip_route, sizeof(ip_route));
     assert(ip);
     assert(!strcmp(ip, "192.168.1.3"));
+    free(ip);
 }
 
 static void test_get_ip_no_wlan() {

app/tests/test_control_msg_serialize.c

@@ -126,12 +126,13 @@ static void test_serialize_inject_scroll_event(void) {
             },
             .hscroll = 1,
             .vscroll = -1,
+            .buttons = 1,
         },
     };
 
     unsigned char buf[CONTROL_MSG_MAX_SIZE];
     size_t size = control_msg_serialize(&msg, buf);
-    assert(size == 21);
+    assert(size == 25);
 
     const unsigned char expected[] = {
         CONTROL_MSG_TYPE_INJECT_SCROLL_EVENT,
@@ -139,6 +140,7 @@ static void test_serialize_inject_scroll_event(void) {
         0x04, 0x38, 0x07, 0x80, // 1080 1920
         0x00, 0x00, 0x00, 0x01, // 1
         0xFF, 0xFF, 0xFF, 0xFF, // -1
+        0x00, 0x00, 0x00, 0x01, // 1
     };
     assert(!memcmp(buf, expected, sizeof(expected)));
 }

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

@@ -71,12 +71,13 @@ public final class ControlMessage {
         return msg;
     }
 
-    public static ControlMessage createInjectScrollEvent(Position position, int hScroll, int vScroll) {
+    public static ControlMessage createInjectScrollEvent(Position position, int hScroll, int vScroll, int buttons) {
         ControlMessage msg = new ControlMessage();
         msg.type = TYPE_INJECT_SCROLL_EVENT;
         msg.position = position;
         msg.hScroll = hScroll;
         msg.vScroll = vScroll;
+        msg.buttons = buttons;
         return msg;
     }
 

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 = 20;
+    static final int INJECT_SCROLL_EVENT_PAYLOAD_LENGTH = 24;
     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;
@@ -154,7 +154,8 @@ public class ControlMessageReader {
         Position position = readPosition(buffer);
         int hScroll = buffer.getInt();
         int vScroll = buffer.getInt();
-        return ControlMessage.createInjectScrollEvent(position, hScroll, vScroll);
+        int buttons = buffer.getInt();
+        return ControlMessage.createInjectScrollEvent(position, hScroll, vScroll, buttons);
     }
 
     private ControlMessage parseBackOrScreenOnEvent() {

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

@@ -98,7 +98,7 @@ public class Controller {
                 break;
             case ControlMessage.TYPE_INJECT_SCROLL_EVENT:
                 if (device.supportsInputEvents()) {
-                    injectScroll(msg.getPosition(), msg.getHScroll(), msg.getVScroll());
+                    injectScroll(msg.getPosition(), msg.getHScroll(), msg.getVScroll(), msg.getButtons());
                 }
                 break;
             case ControlMessage.TYPE_BACK_OR_SCREEN_ON:
@@ -221,7 +221,7 @@ public class Controller {
         return device.injectEvent(event, Device.INJECT_MODE_ASYNC);
     }
 
-    private boolean injectScroll(Position position, int hScroll, int vScroll) {
+    private boolean injectScroll(Position position, int hScroll, int vScroll, int buttons) {
         long now = SystemClock.uptimeMillis();
         Point point = device.getPhysicalPoint(position);
         if (point == null) {
@@ -239,7 +239,7 @@ public class Controller {
         coords.setAxisValue(MotionEvent.AXIS_VSCROLL, vScroll);
 
         MotionEvent event = MotionEvent
-                .obtain(lastTouchDown, now, MotionEvent.ACTION_SCROLL, 1, pointerProperties, pointerCoords, 0, 0, 1f, 1f, DEFAULT_DEVICE_ID, 0,
+                .obtain(lastTouchDown, now, MotionEvent.ACTION_SCROLL, 1, pointerProperties, pointerCoords, 0, buttons, 1f, 1f, DEFAULT_DEVICE_ID, 0,
                         InputDevice.SOURCE_MOUSE, 0);
         return device.injectEvent(event, Device.INJECT_MODE_ASYNC);
     }

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

@@ -128,6 +128,7 @@ public class ControlMessageReaderTest {
         dos.writeShort(1920);
         dos.writeInt(1);
         dos.writeInt(-1);
+        dos.writeInt(1);
 
         byte[] packet = bos.toByteArray();
 
@@ -144,6 +145,7 @@ public class ControlMessageReaderTest {
         Assert.assertEquals(1920, event.getPosition().getScreenSize().getHeight());
         Assert.assertEquals(1, event.getHScroll());
         Assert.assertEquals(-1, event.getVScroll());
+        Assert.assertEquals(1, event.getButtons());
     }
 
     @Test