Add horizontal scrolling support for HID mouse

PR #6172 <https://github.com/Genymobile/scrcpy/pull/6172>
Fix HID mouse support with SDL precise input
2026-03-03 18:54:27 +01:00 · 2025-06-20 18:31:31 +02:00 · 2025-06-20 18:31:24 +02:00 · 2025-06-20 18:31:17 +02:00 · 2025-06-20 18:30:50 +02:00
2 changed files with 11 additions and 6 deletions
--- a/app/src/control_msg.c
+++ b/app/src/control_msg.c
@@ -127,10 +127,14 @@ sc_control_msg_serialize(const struct sc_control_msg *msg, uint8_t *buf) {
            return 32;
        case SC_CONTROL_MSG_TYPE_INJECT_SCROLL_EVENT:
            write_position(&buf[1], &msg->inject_scroll_event.position);
-            int16_t hscroll =
-                sc_float_to_i16fp(msg->inject_scroll_event.hscroll);
-            int16_t vscroll =
-                sc_float_to_i16fp(msg->inject_scroll_event.vscroll);
+            // Accept values in the range [-16, 16].
+            // Normalize to [-1, 1] in order to use sc_float_to_i16fp().
+            float hscroll_norm = msg->inject_scroll_event.hscroll / 16;
+            hscroll_norm = CLAMP(hscroll_norm, -1, 1);
+            float vscroll_norm = msg->inject_scroll_event.vscroll / 16;
+            vscroll_norm = CLAMP(vscroll_norm, -1, 1);
+            int16_t hscroll = sc_float_to_i16fp(hscroll_norm);
+            int16_t vscroll = sc_float_to_i16fp(vscroll_norm);
            sc_write16be(&buf[13], (uint16_t) hscroll);
            sc_write16be(&buf[15], (uint16_t) vscroll);
            sc_write32be(&buf[17], msg->inject_scroll_event.buttons);
--- a/server/src/main/java/com/genymobile/scrcpy/control/ControlMessageReader.java
+++ b/server/src/main/java/com/genymobile/scrcpy/control/ControlMessageReader.java
@@ -112,8 +112,9 @@ public class ControlMessageReader {

    private ControlMessage parseInjectScrollEvent() throws IOException {
        Position position = parsePosition();
-        float hScroll = Binary.i16FixedPointToFloat(dis.readShort());
-        float vScroll = Binary.i16FixedPointToFloat(dis.readShort());
+        // Binary.i16FixedPointToFloat() decodes values assuming the full range is [-1, 1], but the actual range is [-16, 16].
+        float hScroll = Binary.i16FixedPointToFloat(dis.readShort()) * 16;
+        float vScroll = Binary.i16FixedPointToFloat(dis.readShort()) * 16;
        int buttons = dis.readInt();
        return ControlMessage.createInjectScrollEvent(position, hScroll, vScroll, buttons);
    }
Author	SHA1	Message	Date
Romain Vimont	b81e0f92b5	Add horizontal scrolling support for HID mouse PR #6172 <https://github.com/Genymobile/scrcpy/pull/6172>	2025-06-20 18:31:31 +02:00
Romain Vimont	be40ee5dd9	Fix HID mouse support with SDL precise input Over HID, only integral scroll values can be sent. When SDL precise scrolling is active, scroll events may include fractional values (e.g., 0.05), which are truncated to 0 in the HID event. To fix the problem, use the integral scroll value reported by SDL, which internally accumulates fractional deltas. Fixes #6156 <https://github.com/Genymobile/scrcpy/issues/6156> PR #6172 <https://github.com/Genymobile/scrcpy/pull/6172>	2025-06-20 18:31:24 +02:00
Romain Vimont	0498459c1f	Extend value range for SDK mouse scrolling SDL precise scrolling can sometimes produce values greater than 1 or less than -1. On the wire, the value is encoded as a 16-bit fixed-point number. Previously, the range was interpreted as [-1, 1], using 1 bit for the integral part (the sign) and 15 bits for the fractional part. To support larger values, interpret the range as [-16, 16] instead, using 5 bits for the integral part and 11 bits for the fractional part (which is more than enough). PR #6172 <https://github.com/Genymobile/scrcpy/pull/6172>	2025-06-20 18:31:17 +02:00
Romain Vimont	9787fe5d26	Preserve original scroll values in mouse event Clamp scroll values to [-1, 1] only for the SDK mouse. HID mouse implementations perform their own clamping to [-127, 127] (in hid_mouse.c). PR #6172 <https://github.com/Genymobile/scrcpy/pull/6172>	2025-06-20 18:30:50 +02:00