From 0498459c1f18c268bb1ac0fb8318631dcac51a11 Mon Sep 17 00:00:00 2001 From: Romain Vimont Date: Fri, 20 Jun 2025 09:06:10 +0200 Subject: [PATCH] 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 --- app/src/control_msg.c | 12 ++++++++---- app/src/mouse_sdk.c | 4 ++-- .../scrcpy/control/ControlMessageReader.java | 5 +++-- 3 files changed, 13 insertions(+), 8 deletions(-) diff --git a/app/src/control_msg.c b/app/src/control_msg.c index e78f0c57..e46c6165 100644 --- 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); diff --git a/app/src/mouse_sdk.c b/app/src/mouse_sdk.c index 1b05d02b..7eceffa7 100644 --- a/app/src/mouse_sdk.c +++ b/app/src/mouse_sdk.c @@ -113,8 +113,8 @@ sc_mouse_processor_process_mouse_scroll(struct sc_mouse_processor *mp, .type = SC_CONTROL_MSG_TYPE_INJECT_SCROLL_EVENT, .inject_scroll_event = { .position = event->position, - .hscroll = CLAMP(event->hscroll, -1, 1), - .vscroll = CLAMP(event->vscroll, -1, 1), + .hscroll = event->hscroll, + .vscroll = event->vscroll, .buttons = convert_mouse_buttons(event->buttons_state), }, }; diff --git a/server/src/main/java/com/genymobile/scrcpy/control/ControlMessageReader.java b/server/src/main/java/com/genymobile/scrcpy/control/ControlMessageReader.java index e503ec61..830a7ec7 100644 --- 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); }