PATCH: XWin multiwindow+multiscreen for negative screen coordinates

[Earle F. Philhower III]

Howdy,

There is a bug in the way XWin handles Windows screen coordinates when
it's run on a system with legal negative position values.  That is, there
is a monitor to the left of the primary monitor, whose screen coords are
(-xxx,0), and the global screen coords are from (-xxx,0) to (+xxx,0).  You
can reproduce this on a 2 head system by setting the rightmost head to be
the Control Panel->Display Settings->Settings->Use this device as my
primary monitor, and then running "XWin.exe -multiwindow -multiplemonitors"

The fix is to offset screen coords by SM_XVIRTUALSCREEN/SM_YVIRTUALSCREEN
whenever you are mapping to/from root window coords (window positioning,
mouse movements).

diff -w -patch changes to winmultiwindowwindow.c are:

-8<-------------------------------------------------------------------
*** orig        Sun May 11 11:47:45 2003
--- winmultiwindowwindow.c      Sun May 11 11:57:24 2003
*************** winPositionWindowMultiWindow (WindowPtr
*** 194,199 ****
--- 194,203 ----
     iX = pWin->drawable.x;
     iY = pWin->drawable.y;

+   /* Root coord(0,0) is really (-X, -Y) */
+   iX += GetSystemMetrics(SM_XVIRTUALSCREEN);
+   iY += GetSystemMetrics(SM_YVIRTUALSCREEN);
+
     /* Get the height and width of the X window */
     iWidth = pWin->drawable.width;
     iHeight = pWin->drawable.height;
*************** winTopLevelWindowProc (HWND hwnd, UINT m
*** 778,783 ****
--- 782,791 ----
         /* Translate the client area mouse coordinates to screen 
coordinates */
         ClientToScreen (hwnd, &ptMouse);

+       /* Screen Coords from (-X,-Y) => Root Window (0,0) */
+       ptMouse.x -= GetSystemMetrics(SM_XVIRTUALSCREEN);
+       ptMouse.y -= GetSystemMetrics(SM_YVIRTUALSCREEN);
+
         /* We can't do anything without privates */
         if (s_pScreenPriv == NULL || s_pScreenInfo->fIgnoreInput)
           break;
*************** winTopLevelWindowProc (HWND hwnd, UINT m
*** 907,912 ****
--- 915,925 ----
         /* Translate the client area mouse coordinates to screen 
coordinates */
         ClientToScreen (hwnd, &ptMouse);

+       /* Screen Coords from (-X,-Y) => Root Window (0,0) */
+       ptMouse.left -= GetSystemMetrics(SM_XVIRTUALSCREEN);
+       ptMouse.top  -= GetSystemMetrics(SM_YVIRTUALSCREEN);
+
+
         /* Pass the message to the root window */
         SendMessage (hwndScreen, message, wParam, MAKELONG(ptMouse.x, 
ptMouse.y));
         return  0;
*************** winTopLevelWindowProc (HWND hwnd, UINT m
*** 1063,1071 ****
           SendConfigureNotify (pWin);

         /* Tell X that the window is moving */
         (s_pScreen->MoveWindow) (pWin,
!                                (int)(short) LOWORD(lParam) - wBorderWidth 
(pWin),
!                                (int)(short) HIWORD(lParam) - wBorderWidth 
(pWin),
                                  pWin->nextSib,
                                  VTMove);
         return 0;
--- 1076,1085 ----
           SendConfigureNotify (pWin);

         /* Tell X that the window is moving */
+       /* Be sure to map from screen (-X,-Y) to (0,0) root coords */
         (s_pScreen->MoveWindow) (pWin,
!                                (int)(short) LOWORD(lParam) - wBorderWidth 
(pWin) - GetSystemMetrics(SM_XVIRTUALSCREEN),
!                                (int)(short) HIWORD(lParam) - wBorderWidth 
(pWin) - GetSystemMetrics(SM_YVIRTUALSCREEN),
                                  pWin->nextSib,
                                  VTMove);
         return 0;
*************** winTopLevelWindowProc (HWND hwnd, UINT m
*** 1220,1228 ****
               SendConfigureNotify (pWin);

             /* Tell the X server that the window is being resized */
             (s_pScreen->ResizeWindow) (pWin,
!                                      pWinPriv->iX - wBorderWidth (pWin),
!                                      pWinPriv->iY - wBorderWidth (pWin),
                                        pWinPriv->iWidth,
                                        pWinPriv->iHeight,
                                        pWin->nextSib);
--- 1234,1243 ----
               SendConfigureNotify (pWin);

             /* Tell the X server that the window is being resized */
+           /* Map from screen (-X,-Y) to (0,0) root coords */
             (s_pScreen->ResizeWindow) (pWin,
!                                      pWinPriv->iX - wBorderWidth (pWin) - 
GetSystemMetrics(SM_XVIRTUALSCREEN),
!                                      pWinPriv->iY - wBorderWidth (pWin) - 
GetSystemMetrics(SM_YVIRTUALSCREEN),
                                        pWinPriv->iWidth,
                                        pWinPriv->iHeight,
                                        pWin->nextSib);
*************** winTopLevelWindowProc (HWND hwnd, UINT m
*** 1316,1321 ****
--- 1331,1340 ----
             /* Get the current position of the mouse cursor */
             GetCursorPos (&point);

+           /* Map from screen (-x,-y) to root (0,0) */
+           point.x -= GetSystemMetrics(SM_XVIRTUALSCREEN);
+           point.y -= GetSystemMetrics(SM_YVIRTUALSCREEN);
+
             /* Deliver absolute cursor position to X Server */
             miPointerAbsoluteCursor (point.x, point.y,
                                      g_c32LastInputEventTime = 
GetTickCount ());
*************** winCreateWindowsWindow (WindowPtr pWin)
*** 1358,1363 ****
--- 1377,1386 ----
     iX = pWin->drawable.x;
     iY = pWin->drawable.y;

+   /* Map from root coord (0,0) to screen (-X, -Y) */
+   iX += GetSystemMetrics(SM_XVIRTUALSCREEN);
+   iY += GetSystemMetrics(SM_YVIRTUALSCREEN);
+
     iWidth = pWin->drawable.width;
     iHeight = pWin->drawable.height;

-8<-------------------------------------------------------------------

-Earle F. Philhower, III
  earle@ziplabel.com
  cdrlabel - ZipLabel - FlpLabel
  http://www.cdrlabel.com
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