Fix high DPI breaking edge detection and mouse delta calculation #5030

src/lib/platform/MSWindowsScreen.cpp

@@ -31,6 +31,7 @@
 #include "synergy/App.h"
 #include "synergy/ArgsBase.h"
 #include "synergy/ClientApp.h"
+#include "synergy/DpiHelper.h"
 #include "mt/Lock.h"
 #include "mt/Thread.h"
 #include "arch/win32/ArchMiscWindows.h"
@@ -143,6 +144,11 @@ MSWindowsScreen::MSWindowsScreen(
 								this, &MSWindowsScreen::updateKeysCB),
 							stopOnDeskSwitch);
 		m_keyState    = new MSWindowsKeyState(m_desks, getEventTarget(), m_events);
+
+		DpiHelper::calculateDpi(
+			GetSystemMetrics(SM_CXVIRTUALSCREEN),
+			GetSystemMetrics(SM_CYVIRTUALSCREEN));
+
 		updateScreenShape();
 		m_class       = createWindowClass();
 		m_window      = createWindow(m_class, "Synergy");
@@ -1347,6 +1353,14 @@ MSWindowsScreen::onMouseButton(WPARAM wParam, LPARAM lParam)
 bool
 MSWindowsScreen::onMouseMove(SInt32 mx, SInt32 my)
 {
+	SInt32 originalMX = mx;
+	SInt32 originalMY = my;
+
+	if (DpiHelper::s_dpiScaled) {
+		mx = (SInt32)(mx / DpiHelper::getDpi());
+		my = (SInt32)(my / DpiHelper::getDpi());
+	}
+
 	// compute motion delta (relative to the last known
 	// mouse position)
 	SInt32 x = mx - m_xCursor;
@@ -1370,7 +1384,7 @@ MSWindowsScreen::onMouseMove(SInt32 mx, SInt32 my)
 		// motion on primary screen
 		sendEvent(
 			m_events->forIPrimaryScreen().motionOnPrimary(),
-			MotionInfo::alloc(m_xCursor, m_yCursor));
+			MotionInfo::alloc(originalMX, originalMY));
 
 		if (m_buttons[kButtonLeft] == true && m_draggingStarted == false) {
 			m_draggingStarted = true;
@@ -1527,20 +1541,25 @@ MSWindowsScreen::warpCursorNoFlush(SInt32 x, SInt32 y)
 	POINT cursorPos;
 	GetCursorPos(&cursorPos);
 
-	if ((cursorPos.x != x) && (cursorPos.y != y)) {
-		LOG((CLOG_DEBUG "SetCursorPos did not work; using fakeMouseMove instead"));
-		
-		// when at Vista/7 login screen, SetCursorPos does not work (which could be
-		// an MS security feature). instead we can use fakeMouseMove, which calls
-		// mouse_event.
-		// IMPORTANT: as of implementing this function, it has an annoying side 
-		// effect; instead of the mouse returning to the correct exit point, it
-		// returns to the center of the screen. this could have something to do with
-		// the center screen warping technique used (see comments for onMouseMove
-		// definition).
-		fakeMouseMove(x, y);
+	// there is a bug or round error in SetCursorPos and GetCursorPos on 
+	// a high DPI setting. The check here is for Vista/7 login screen. 
+	// since this feature is mainly for client, so only check on client.
+	if (!isPrimary()) {
+		if ((cursorPos.x != x) && (cursorPos.y != y)) {
+			LOG((CLOG_DEBUG "SetCursorPos did not work; using fakeMouseMove instead"));
+			LOG((CLOG_DEBUG "cursor pos %d, %d expected pos %d, %d", cursorPos.x, cursorPos.y, x, y));
+			// when at Vista/7 login screen, SetCursorPos does not work (which could be
+			// an MS security feature). instead we can use fakeMouseMove, which calls
+			// mouse_event.
+			// IMPORTANT: as of implementing this function, it has an annoying side 
+			// effect; instead of the mouse returning to the correct exit point, it
+			// returns to the center of the screen. this could have something to do with
+			// the center screen warping technique used (see comments for onMouseMove
+			// definition).
+			fakeMouseMove(x, y);
+		}
 	}
-	
+
 	// yield the CPU.  there's a race condition when warping:
 	//   a hardware mouse event occurs
 	//   the mouse hook is not called because that process doesn't have the CPU
@@ -1582,16 +1601,25 @@ MSWindowsScreen::ignore() const
 void
 MSWindowsScreen::updateScreenShape()
 {
-	// get shape
+	// get shape and center
+	if (DpiHelper::s_dpiScaled) {
+		m_w = (SInt32)DpiHelper::s_resolutionWidth;
+		m_h = (SInt32)DpiHelper::s_resolutionHeight;
+
+		m_xCenter = (SInt32)DpiHelper::s_primaryWidthCenter;
+		m_yCenter = (SInt32)DpiHelper::s_primaryHeightCenter;
+	}
+	else {
+		m_w = GetSystemMetrics(SM_CXVIRTUALSCREEN);
+		m_h = GetSystemMetrics(SM_CYVIRTUALSCREEN);
+
+		m_xCenter = GetSystemMetrics(SM_CXSCREEN) >> 1;
+		m_yCenter = GetSystemMetrics(SM_CYSCREEN) >> 1;
+	}
+
+	// get position
 	m_x = GetSystemMetrics(SM_XVIRTUALSCREEN);
 	m_y = GetSystemMetrics(SM_YVIRTUALSCREEN);
-	m_w = GetSystemMetrics(SM_CXVIRTUALSCREEN);
-	m_h = GetSystemMetrics(SM_CYVIRTUALSCREEN);
-
-	// get center for cursor
-	m_xCenter = GetSystemMetrics(SM_CXSCREEN) >> 1;
-	m_yCenter = GetSystemMetrics(SM_CYSCREEN) >> 1;
-
 	// check for multiple monitors
 	m_multimon = (m_w != GetSystemMetrics(SM_CXSCREEN) ||
 				  m_h != GetSystemMetrics(SM_CYSCREEN));

src/lib/server/BaseClientProxy.h

@@ -51,6 +51,12 @@ public:
 	*/
 	void				getJumpCursorPos(SInt32& x, SInt32& y) const;
 
+	//! Get cursor position
+	/*!
+	Return if this proxy is for client or primary.
+	*/
+	virtual bool		isPrimary() const { return false; }
+
 	//@}
 
 	// IScreen

src/lib/server/PrimaryClient.h

@@ -148,7 +148,7 @@ public:
 
 	virtual synergy::IStream*
 						getStream() const { return NULL; }
-
+	bool				isPrimary() const { return true; }
 private:
 	synergy::Screen*	m_screen;
 	bool				m_clipboardDirty[kClipboardEnd];

src/lib/server/Server.cpp

@@ -33,6 +33,7 @@
 #include "synergy/KeyState.h"
 #include "synergy/Screen.h"
 #include "synergy/PacketStreamFilter.h"
+#include "synergy/DpiHelper.h"
 #include "net/TCPSocket.h"
 #include "net/IDataSocket.h"
 #include "net/IListenSocket.h"
@@ -2000,8 +2001,18 @@ Server::onMouseMoveSecondary(SInt32 dx, SInt32 dy)
 			m_sendFileThread = NULL;
 		}
 
+		SInt32 newX = m_x;
+		SInt32 newY = m_y;
+
+		if (DpiHelper::s_dpiScaled) {
+			// only scale if it's going back to server
+			if (newScreen->isPrimary()) {
+				newX = (SInt32)(newX / DpiHelper::getDpi());
+				newY = (SInt32)(newY / DpiHelper::getDpi());
+			}
+		}
 		// switch screens
-		switchScreen(newScreen, m_x, m_y, false);
+		switchScreen(newScreen, newX, newY, false);
 	}
 	else {
 		// same screen.  clamp mouse to edge.