New subject: [Bug 24464] UpdateLayeredWindow() generates WM_SIZE when it should not, and other non-matching behavior

19 Sep 2010


      http://bugs.winehq.org/show_bug.cgi?id=24464
Summary: UpdateLayeredWindow() generates WM_SIZE when it should
                    not, and other non-matching behavior
           Product: Wine
           Version: 1.1.44
          Platform: All
        OS/Version: All
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: user32
        AssignedTo: wine-bugs@winehq.org
        ReportedBy: ivucica@gmail.com
Created an attachment (id=30866)
 --> (http://bugs.winehq.org/attachment.cgi?id=30866)
test case
Below are pasted the notes from the attached source code, for easier reference.
The most important bug is #4, erroneous generation of WM_SIZE when they should
not be generated. I did not feel like creating several bug reports, feel free
to split if necessary.
Attached is the test case demonstrating the issues.  To compile test case using
MinGW, use following makefile:
CC=i386-mingw32msvc-gcc
all:
        $(CC) -o updatelayeredwindow_demo.exe -lole32 -lcomdlg32 -luser32
-lwinmm main.c  -lgdi32
Please compare behavior between XP and Wine. You can make the window reduce its
size by left clicking. Then observe the log. You can notice that on XP, WM_SIZE
is not generated. On Wine, it is continuously generated. Bugs #1-#3 can also be
tested easily by modifying the source code as described and comparing output.
I presume the bug happens everywhere, although it was tested only on OS X.
At least one application development framework, Cocotron, depends on correct
behavior for WM_SIZE. Cocotron reimplements OS X's Cocoa API to create source
level compatibility. Wine is the easiest way to test the Cocotron executables,
since Cocotron compiles on OS X to produce Windows binaries. Otherwise, one
needs to have a machine (either real or virtual) that runs Windows in order to
test software.
However, this bug blocks testing of any application that uses "sheets", since
sheets are animated using UpdateLayeredWindow(). Sheets are captionless modal
dialogs that appear on their owner window, and as their parent moves, they move
as well. They are quite ubiquitous on Mac OS X and in Cocoa.
Description of Cocotron internals and cause for this bug: 
Animations use class instance's _size member, which is updated when WM_SIZE is
sent. This member should not ordinarily be updated during execution of
animation function, but it gets updated because WM_SIZE is sent.
// TESTED ON WINDOWS XP with wine-1.1.44
// bug #1: If we pass 0 as first argument to CreateWindowEx(), Windows ignore 
//         UpdateLayeredWindow(). Wine does not.
// bug #2: If we pass WS_EX_LAYERED as first argument to CreateWindowEx(),
Windows does not 
//         display the window except in taskbar. Wine displays it, and even
dispatches 
//         WM_LBUTTONDOWN. Function should also fail, with GetLastError()
returning 0.
//     #2a: Additionally, same thing happens if we do not pass a DC as fifth
argument to
//          UpdateLayeredWindow().
// bug #3: In WM_LBUTTONDOWN, there is the following call.
//           UpdateLayeredWindow(hWnd, GetDC(hWnd), &ptSrc, &sizeWnd, memDC,
&origin, RGB(0xFF,0xFF,0xFF), &blend, ULW_OPAQUE);
//         if we pass NULL instead of memDC, Windows do not resize the window.
Wine happily resizes it
//         Additionally function should fail.
***********************************************************************
***********************************************************************
// MOST IMPORTANT:
// bug #4: If UpdateLayeredWindow() resizes the window, Windows do not generate
WM_SIZE.
//         Wine does generate WM_SIZE.
//         This causes a bug in every application displaying "sheets" that is 
//         developed using Cocotron (http://cocotron.org/). "Sheets" in Mac OS
X are 
//         per-window modal popups attached to top of the window.
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[Bug 24464] New: UpdateLayeredWindow() generates WM_SIZE when it should not, and other non-matching behavior