From ba4841c0c6530c643dd3bd9327fec94c02f20d6b Mon Sep 17 00:00:00 2001
From: Angeldark Raymaker <dark.angel_raven@yahoo.com.au>
Date: Sat, 19 Oct 2024 20:54:10 +0100
Subject: [PATCH] FIRE-30873: Ctrl press on trackpad for fine control

---
 indra/newview/fsvirtualtrackpad.cpp | 103 ++++++++++++++++++++--------
 indra/newview/fsvirtualtrackpad.h   |   7 ++
 2 files changed, 83 insertions(+), 27 deletions(-)

diff --git a/indra/newview/fsvirtualtrackpad.cpp b/indra/newview/fsvirtualtrackpad.cpp
index 64b71a44bd..14335e1774 100644
--- a/indra/newview/fsvirtualtrackpad.cpp
+++ b/indra/newview/fsvirtualtrackpad.cpp
@@ -62,6 +62,7 @@ FSVirtualTrackpad::FSVirtualTrackpad(const FSVirtualTrackpad::Params &p)
     _valueZ = _pinchValueZ = 0;
 
     _thumbClickOffsetX = _thumbClickOffsetY = _pinchThumbClickOffsetX = _pinchThumbClickOffsetY = 0;
+    _posXwhenCtrlDown = _posYwhenCtrlDown = -1;
 
     LLViewBorder::Params border = p.border;
     border.rect(border_rect);
@@ -288,37 +289,86 @@ bool FSVirtualTrackpad::handleHover(S32 x, S32 y, MASK mask)
     if (!hasMouseCapture())
         return true;
 
-    S32 correctedX, correctedY;
-    if (doingPinchMode)
-    {
-        correctedX = x + _pinchThumbClickOffsetX;
-        correctedY = y + _pinchThumbClickOffsetY;
-    }
-    else
-    {
-        correctedX = x + _thumbClickOffsetX;
-        correctedY = y + _thumbClickOffsetY;
-    }
-
-    if (!mInfiniteScrollMode)
-        wrapOrClipCursorPosition(&correctedX, &correctedY);
-
-    if (doingPinchMode)
-    {
-        _pinchValueX = correctedX;
-        _pinchValueY = correctedY;
-    }
-    else
-    {
-        _valueX = correctedX;
-        _valueY = correctedY;
-    }
+    S32 deltaX, deltaY;
+    getHoverMovementDeltas(x, y, mask, &deltaX, &deltaY);
+    applyHoverMovementDeltas(deltaX, deltaY, mask);
 
     onCommit();
 
     return true;
 }
 
+void FSVirtualTrackpad::getHoverMovementDeltas(S32 x, S32 y, MASK mask, S32* deltaX, S32* deltaY)
+{
+    if (!deltaX || !deltaY)
+        return;
+
+    S32 fromX, fromY;
+    fromX = doingPinchMode ? _pinchValueX : _valueX;
+    fromY = doingPinchMode ? _pinchValueY : _valueY;
+
+    if (mask & MASK_CONTROL)
+    {
+        if (!heldDownCtrlBefore())
+        {
+            _posXwhenCtrlDown = x;
+            _posYwhenCtrlDown = y;
+        }
+
+        if (doingPinchMode)
+        {
+            *deltaX = _posXwhenCtrlDown - (_posXwhenCtrlDown - x) / 8 + _pinchThumbClickOffsetX - fromX;
+            *deltaY = _posYwhenCtrlDown - (_posYwhenCtrlDown - y) / 8 + _pinchThumbClickOffsetY - fromY;
+        }
+        else
+        {
+            *deltaX = _posXwhenCtrlDown - (_posXwhenCtrlDown - x) / 8 + _thumbClickOffsetX - fromX;
+            *deltaY = _posYwhenCtrlDown - (_posYwhenCtrlDown - y) / 8 + _thumbClickOffsetY - fromY;
+        }
+    }
+    else
+    {
+        if (heldDownCtrlBefore())
+        {
+            _thumbClickOffsetX = fromX - x;
+            _thumbClickOffsetY = fromY - y;
+            _posXwhenCtrlDown = _posYwhenCtrlDown = -1;
+        }
+
+        if (doingPinchMode)
+        {
+            *deltaX = x + _pinchThumbClickOffsetX - fromX;
+            *deltaY = y + _pinchThumbClickOffsetY - fromY;
+        }
+        else
+        {
+            *deltaX = x + _thumbClickOffsetX - fromX;
+            *deltaY = y + _thumbClickOffsetY - fromY;
+        }
+    }
+}
+
+bool FSVirtualTrackpad::heldDownCtrlBefore() const { return _posXwhenCtrlDown >= 0 && _posYwhenCtrlDown >= 0; }
+
+void FSVirtualTrackpad::applyHoverMovementDeltas(S32 deltaX, S32 deltaY, MASK mask)
+{
+    if (doingPinchMode)
+    {
+        _pinchValueX += deltaX;
+        _pinchValueY += deltaY;
+        if (!mInfiniteScrollMode)  // then constrain the cursor within control area
+            wrapOrClipCursorPosition(&_pinchValueX, &_pinchValueY);
+    }
+    else
+    {
+        _valueX += deltaX;
+        _valueY += deltaY;
+
+        if (!mInfiniteScrollMode)  // then constrain the cursor within control area
+            wrapOrClipCursorPosition(&_valueX, &_valueY);
+    }
+}
+
 LLVector3 FSVirtualTrackpad::normalizePixelPos(S32 x, S32 y, S32 z) const
 {
     LLVector3 result;
@@ -368,7 +418,7 @@ bool FSVirtualTrackpad::handleMouseUp(S32 x, S32 y, MASK mask)
     if (hasMouseCapture())
     {
         gFocusMgr.setMouseCapture(NULL);
-
+        _posXwhenCtrlDown = _posYwhenCtrlDown = -1;
         make_ui_sound("UISndClickRelease");
     }
 
@@ -382,7 +432,6 @@ bool FSVirtualTrackpad::handleMouseDown(S32 x, S32 y, MASK mask)
         determineThumbClickError(x, y);
         updateClickErrorIfInfiniteScrolling();
         gFocusMgr.setMouseCapture(this);
-
         make_ui_sound("UISndClick");
     }
 
diff --git a/indra/newview/fsvirtualtrackpad.h b/indra/newview/fsvirtualtrackpad.h
index d735557006..da6e3e383b 100644
--- a/indra/newview/fsvirtualtrackpad.h
+++ b/indra/newview/fsvirtualtrackpad.h
@@ -101,6 +101,10 @@ private:
     void      convertNormalizedToPixelPos(F32 x, F32 y, F32 z, S32* valX, S32* valY, S32* valZ);
     LLVector3 normalizePixelPos(S32 x, S32 y, S32 z) const;
 
+    void getHoverMovementDeltas(S32 x, S32 y, MASK mask, S32* deltaX, S32* deltaY);
+    void applyHoverMovementDeltas(S32 deltaX, S32 deltaY, MASK mask);
+    bool heldDownCtrlBefore() const;
+
     LLUIImage* mImgMoonBack;
     LLUIImage* mImgMoonFront;
     LLUIImage* mImgSunBack;
@@ -144,6 +148,9 @@ private:
     S32 _thumbClickOffsetY;
     S32 _pinchThumbClickOffsetX;
     S32 _pinchThumbClickOffsetY;
+
+    S32 _posXwhenCtrlDown;
+    S32 _posYwhenCtrlDown;
 };
 #endif