get display DPI info to scale mouse movement

common/include/common/KVMFR.h

@@ -57,7 +57,7 @@ typedef enum CursorType
 CursorType;
 
 #define KVMFR_MAGIC   "KVMFR---"
-#define KVMFR_VERSION 5
+#define KVMFR_VERSION 6
 
 typedef struct KVMFR
 {
@@ -80,12 +80,13 @@ KVMFRCursor;
 
 typedef struct KVMFRFrame
 {
-  uint32_t  formatVer;   // the frame format version number
+  uint32_t  formatVer;         // the frame format version number
-  FrameType type;        // the frame data type
+  FrameType type;              // the frame data type
-  uint32_t  width;       // the width
+  uint32_t  width;             // the width
-  uint32_t  height;      // the height
+  uint32_t  height;            // the height
-  uint32_t  stride;      // the row stride (zero if compressed data)
+  uint32_t  stride;            // the row stride (zero if compressed data)
-  uint32_t  pitch;       // the row pitch  (stride in bytes or the compressed frame size)
+  uint32_t  pitch;             // the row pitch  (stride in bytes or the compressed frame size)
-  uint32_t  offset;      // offset from the start of this header to the FrameBuffer header
+  uint32_t  offset;            // offset from the start of this header to the FrameBuffer header
+  uint32_t  mouseScalePercent; // movement scale factor of the mouse (relates to DPI of display, 100 = no scale)
 }
 KVMFRFrame;

common/include/common/dpi.h

@@ -0,0 +1,25 @@
+/*
+Looking Glass - KVM FrameRelay (KVMFR) Client
+Copyright (C) 2017-2020 Geoffrey McRae <geoff@hostfission.com>
+https://looking-glass.hostfission.com
+
+This program is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free Software
+Foundation; either version 2 of the License, or (at your option) any later
+version.
+
+This program is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+Place, Suite 330, Boston, MA 02111-1307 USA
+*/
+
+#include <windows.h>
+
+// At 100% scaling, Windows reports 96 DPI.
+#define DPI_100_PERCENT 96
+
+UINT monitor_dpi(HMONITOR hMonitor);

common/src/platform/windows/CMakeLists.txt

@@ -7,6 +7,7 @@ include_directories(
 
 add_library(lg_common_platform_code STATIC
     crash.c
+    dpi.c
     sysinfo.c
     thread.c
     event.c

common/src/platform/windows/dpi.c

@@ -0,0 +1,37 @@
+#include "common/dpi.h"
+#include "common/windebug.h"
+
+typedef enum MONITOR_DPI_TYPE {
+  MDT_EFFECTIVE_DPI,
+  MDT_ANGULAR_DPI,
+  MDT_RAW_DPI,
+  MDT_DEFAULT
+} MONITOR_DPI_TYPE;
+typedef HRESULT (WINAPI *GetDpiForMonitor_t)(HMONITOR hmonitor, MONITOR_DPI_TYPE dpiType, UINT * dpiX, UINT * dpiY);
+
+UINT monitor_dpi(HMONITOR hMonitor)
+{
+  HMODULE shcore = LoadLibraryA("shcore.dll");
+  if (!shcore)
+  {
+    DEBUG_ERROR("Could not load shcore.dll");
+    return DPI_100_PERCENT;
+  }
+
+  GetDpiForMonitor_t GetDpiForMonitor = (GetDpiForMonitor_t) GetProcAddress(shcore, "GetDpiForMonitor");
+  if (!GetDpiForMonitor)
+  {
+    DEBUG_ERROR("Could not find GetDpiForMonitor");
+    return DPI_100_PERCENT;
+  }
+
+  UINT dpiX, dpiY;
+  HRESULT status = GetDpiForMonitor(hMonitor, MDT_EFFECTIVE_DPI, &dpiX, &dpiY);
+  if (FAILED(status))
+  {
+    DEBUG_WINERROR("GetDpiForMonitor failed", status);
+    return DPI_100_PERCENT;
+  }
+
+  return dpiX;
+}

host/include/interface/capture.h

@@ -93,6 +93,7 @@ typedef struct CaptureInterface
   bool          (*deinit         )();
   void          (*free           )();
   unsigned int  (*getMaxFrameSize)();
+  unsigned int  (*getMouseScale  )();
 
   CaptureResult (*capture   )();
   CaptureResult (*waitFrame )(CaptureFrame * frame);

host/platform/Linux/capture/XCB/src/xcb.c

@@ -169,6 +169,11 @@ static unsigned int xcb_getMaxFrameSize()
   return this->width * this->height * 4;
 }
 
+static unsigned int xcb_getMouseScale()
+{
+  return 100;
+}
+
 static CaptureResult xcb_capture()
 {
   assert(this);
@@ -241,6 +246,7 @@ struct CaptureInterface Capture_XCB =
   .deinit          = xcb_deinit,
   .free            = xcb_free,
   .getMaxFrameSize = xcb_getMaxFrameSize,
+  .getMouseScale   = xcb_getMouseScale,
   .capture         = xcb_capture,
   .waitFrame       = xcb_waitFrame,
   .getFrame        = xcb_getFrame,

host/platform/Windows/capture/DXGI/src/dxgi.c

@@ -24,6 +24,7 @@ Place, Suite 330, Boston, MA 02111-1307 USA
 #include "common/option.h"
 #include "common/locking.h"
 #include "common/event.h"
+#include "common/dpi.h"
 
 #include <assert.h>
 #include <stdatomic.h>
@@ -98,12 +99,12 @@ struct iface
   unsigned int  pitch;
   unsigned int  stride;
   CaptureFormat format;
+  unsigned int  dpi;
 
   int  lastPointerX, lastPointerY;
   bool lastPointerVisible;
 };
 
-static bool           dpiDone = false;
 static struct iface * this    = NULL;
 
 // forwards
@@ -210,22 +211,6 @@ static bool dxgi_init()
     DEBUG_INFO("looking-glass-host.exe InstallService");
   }
 
-  // this is required for DXGI 1.5 support to function
-  if (!dpiDone)
-  {
-    DECLARE_HANDLE(DPI_AWARENESS_CONTEXT);
-    #define DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2  ((DPI_AWARENESS_CONTEXT)-4)
-    typedef BOOL (*User32_SetProcessDpiAwarenessContext)(DPI_AWARENESS_CONTEXT value);
-
-    HMODULE user32 = LoadLibraryA("user32.dll");
-    User32_SetProcessDpiAwarenessContext fn;
-    fn = (User32_SetProcessDpiAwarenessContext)GetProcAddress(user32, "SetProcessDpiAwarenessContext");
-    if (fn)
-      fn(DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2);
-    FreeLibrary(user32);
-    dpiDone = true;
-  }
-
   HRESULT          status;
   DXGI_OUTPUT_DESC outputDesc;
 
@@ -388,6 +373,7 @@ static bool dxgi_init()
   IDXGIAdapter1_GetDesc1(this->adapter, &adapterDesc);
   this->width  = outputDesc.DesktopCoordinates.right  - outputDesc.DesktopCoordinates.left;
   this->height = outputDesc.DesktopCoordinates.bottom - outputDesc.DesktopCoordinates.top;
+  this->dpi    = monitor_dpi(outputDesc.Monitor);
   ++this->formatVer;
 
   DEBUG_INFO("Device Descripion: %ls"    , adapterDesc.Description);
@@ -688,6 +674,14 @@ static unsigned int dxgi_getMaxFrameSize()
   return this->height * this->pitch;
 }
 
+static unsigned int dxgi_getMouseScale()
+{
+  assert(this);
+  assert(this->initialized);
+
+  return this->dpi * 100 / DPI_100_PERCENT;
+}
+
 static CaptureResult dxgi_hResultToCaptureResult(const HRESULT status)
 {
   switch(status)
@@ -1013,6 +1007,7 @@ struct CaptureInterface Capture_DXGI =
   .deinit          = dxgi_deinit,
   .free            = dxgi_free,
   .getMaxFrameSize = dxgi_getMaxFrameSize,
+  .getMouseScale   = dxgi_getMouseScale,
   .capture         = dxgi_capture,
   .waitFrame       = dxgi_waitFrame,
   .getFrame        = dxgi_getFrame

host/platform/Windows/capture/NVFBC/src/nvfbc.c

@@ -25,6 +25,7 @@ Place, Suite 330, Boston, MA 02111-1307 USA
 #include "common/framebuffer.h"
 #include "common/event.h"
 #include "common/thread.h"
+#include "common/dpi.h"
 #include <assert.h>
 #include <stdlib.h>
 #include <windows.h>
@@ -44,6 +45,7 @@ struct iface
 
   unsigned int maxWidth , maxHeight;
   unsigned int width    , height;
+  unsigned int dpi;
 
   unsigned int formatVer;
   unsigned int grabWidth, grabHeight, grabStride;
@@ -65,7 +67,7 @@ static struct iface * this = NULL;
 static void nvfbc_free();
 static int pointerThread(void * unused);
 
-static void getDesktopSize(unsigned int * width, unsigned int * height)
+static void getDesktopSize(unsigned int * width, unsigned int * height, unsigned int * dpi)
 {
   HMONITOR    monitor     = MonitorFromWindow(GetDesktopWindow(), MONITOR_DEFAULTTOPRIMARY);
   MONITORINFO monitorInfo = {
@@ -73,6 +75,7 @@ static void getDesktopSize(unsigned int * width, unsigned int * height)
   };
 
   GetMonitorInfo(monitor, &monitorInfo);
+  *dpi = monitor_dpi(monitor);
   CloseHandle(monitor);
 
   *width  = monitorInfo.rcMonitor.right  - monitorInfo.rcMonitor.left;
@@ -163,7 +166,7 @@ static bool nvfbc_create(
 static bool nvfbc_init()
 {
   this->stop = false;
-  getDesktopSize(&this->width, &this->height);
+  getDesktopSize(&this->width, &this->height, &this->dpi);
   lgResetEvent(this->frameEvent);
 
   HANDLE event;
@@ -245,9 +248,14 @@ static unsigned int nvfbc_getMaxFrameSize()
   return this->maxWidth * this->maxHeight * 4;
 }
 
+static unsigned int nvfbc_getMouseScale()
+{
+  return this->dpi * 100 / DPI_100_PERCENT;
+}
+
 static CaptureResult nvfbc_capture()
 {
-  getDesktopSize(&this->width, &this->height);
+  getDesktopSize(&this->width, &this->height, &this->dpi);
   NvFBCFrameGrabInfo grabInfo;
   CaptureResult result = NvFBCToSysCapture(
     this->nvfbc,
@@ -397,6 +405,7 @@ struct CaptureInterface Capture_NVFBC =
   .deinit          = nvfbc_deinit,
   .free            = nvfbc_free,
   .getMaxFrameSize = nvfbc_getMaxFrameSize,
+  .getMouseScale   = nvfbc_getMouseScale,
   .capture         = nvfbc_capture,
   .waitFrame       = nvfbc_waitFrame,
   .getFrame        = nvfbc_getFrame

host/platform/Windows/src/platform.c

@@ -226,6 +226,18 @@ int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine
   // setup a handler for ctrl+c
   SetConsoleCtrlHandler(CtrlHandler, TRUE);
 
+  // enable high DPI awareness
+  // this is required for DXGI 1.5 support to function and also capturing desktops with high DPI
+  DECLARE_HANDLE(DPI_AWARENESS_CONTEXT);
+  #define DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2  ((DPI_AWARENESS_CONTEXT)-4)
+  typedef BOOL (*User32_SetProcessDpiAwarenessContext)(DPI_AWARENESS_CONTEXT value);
+
+  HMODULE user32 = GetModuleHandle("user32.dll");
+  User32_SetProcessDpiAwarenessContext fn;
+  fn = (User32_SetProcessDpiAwarenessContext)GetProcAddress(user32, "SetProcessDpiAwarenessContext");
+  if (fn)
+    fn(DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2);
+
   // create a message window so that our message pump works
   WNDCLASSEX wx    = {};
   wx.cbSize        = sizeof(WNDCLASSEX);
@@ -249,7 +261,6 @@ int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine
   app.messageWnd = CreateWindowEx(0, MAKEINTATOM(class), NULL, 0, 0, 0, 0, 0, NULL, NULL, hInstance, NULL);
 
   // this is needed so that unprivileged processes can send us this message
-  HMODULE user32 = GetModuleHandle("user32.dll");
   _ChangeWindowMessageFilterEx = (PChangeWindowMessageFilterEx)GetProcAddress(user32, "ChangeWindowMessageFilterEx");
   if (_ChangeWindowMessageFilterEx)
     _ChangeWindowMessageFilterEx(app.messageWnd, app.trayRestartMsg, MSGFLT_ALLOW, NULL);

host/src/app.c

@@ -186,13 +186,14 @@ static int frameThread(void * opaque)
         continue;
     }
 
-    fi->formatVer = frame.formatVer;
+    fi->formatVer         = frame.formatVer;
-    fi->width     = frame.width;
+    fi->width             = frame.width;
-    fi->height    = frame.height;
+    fi->height            = frame.height;
-    fi->stride    = frame.stride;
+    fi->stride            = frame.stride;
-    fi->pitch     = frame.pitch;
+    fi->pitch             = frame.pitch;
-    fi->offset    = pageSize - FrameBufferStructSize;
+    fi->offset            = pageSize - FrameBufferStructSize;
-    frameValid    = true;
+    fi->mouseScalePercent = app.iface->getMouseScale();
+    frameValid            = true;
 
     // put the framebuffer on the border of the next page
     // this is to allow for aligned DMA transfers by the receiver