Details
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Bug
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Resolution: Done
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P3: Somewhat important
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4.6.0
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None
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234e849cfc85d5618d2f703bb92701042993d2de
Description
On Win32, when compressing the WM_MOUSEMOVE events, sometimes the wrong coordinate is used. This happens when another app, is simulating events to the Qt Widget by using PostMessage() to post WM_MOUSEMOVE events to the application. The LPARAM has the correct coordinates.
Here is a patch to resolve the issue:
--- src\gui\kernel\qapplication_win.cpp 2010-01-26 07:26:26.348949500 -0800
+++ src\gui\kernel\qapplication_win.cpp_ 2010-01-26 07:30:52.175529500 -0800
@@ -2943,6 +2943,15 @@
MSG *msgPtr = (MSG *)(&msg);
// Update the passed in MSG structure with the
// most recent one.
+ // NOTE: The pt in the MSG structure received from
+ // PeekMessage is sometimes incorrect. Specifically
+ // if the WM_MOUSEMOVE messages are being posted
+ // from a different process. The LPARAM seems
+ // to always be correct though, so use that
+ // to update the pt.x and pt.y fields.
+ mouseMsg.pt.x = GET_X_LPARAM(mouseMsg.lParam);
+ mouseMsg.pt.y = GET_Y_LPARAM(mouseMsg.lParam);
+ ClientToScreen(mouseMsg.hwnd, &mouseMsg.pt);
msgPtr->lParam = mouseMsg.lParam;
msgPtr->wParam = mouseMsg.wParam;
msgPtr->pt = mouseMsg.pt;