Simple FillRect

[Brooks_Van_Horn]

Hi All,

I have a "type (T_RECT) rectp" defined and I'm in a WM_PAINT section in an SDI window. I've created a brush as " hBrush = GetStockObject(WHITE_BRUSH)". I've populated the rect by "bret = GetClientRect(hWndMain, rectp)". All the values look good in the debug window but the program crashes at the statement "iret = FillRect ( hDC, rectp, hBrush)" with the message "Unhandled exception at 0x00007FF7DDFB1CD6 in Pearson.exe: 0xC000041D: An unhandled exception was encountered during a user callback.". I am running Intel Fortran 2016.1.146 in x64 mode on a Win 10 x64 OS.

Any ideas what is wrong here?

Thanks,

Brooks V

[Brooks_Van_Horn]

I forgot to mention that I'm on an ASUS computer with 32GB RAM with an Intel(R) Core(TM) i7-4770 CPU at 3.40GHz processor with 4 cores and hyper-threading turned on.

Brooks V

[andrew_4619]

Do you have "check interfaces compiler" option on? How are hDC and hbrush declared?

[Brooks_Van_Horn]

where do i check on 'check interfaces'? hDC = GetDC(hWndMain)  and hBrush = GetStockObject(WHITE_BRUSH).  I've already done some TextOut and MoveTo/LineTo commands without any errors.

Brooks V

[andrew_4619 · Accepted solution]

Both of those should be of type integer(handle)

In VS

Configuration Properties > Fortran > Diagnostics

at the cmd line it is  \warn:interfaces

It will show and mismatched types call parameters which is one possible cause.

[Brooks_Van_Horn]

Yes they all are integers:

integer(HANDLE),Save,public:: hInst
integer(HANDLE),Save,public:: hWndDlg
integer(HANDLE),Save,public:: hWndMain
Integer(HANDLE),Save,public:: hPen = NULL, hOldPen = NULL
Integer(HANDLE),Save,public:: hBrush = NULL, hOldBrush =  NULL
Integer(HANDLE),Save,public:: hMyFont36 = NULL, hOldFont =  NULL
Integer(HANDLE),Save,public:: hMyFont12= NULL, hMyFont16 =  NULL
Integer(HANDLE),Save,public:: hMyFont20 = NULL, hMyFont24=  NULL
Integer(HANDLE),Save,public:: hDlg = NULL
Integer(HANDLE),Save,public:: hDC = NULL

[Brooks_Van_Horn]

Andrew,

Both places already had the warn:interfaces set so that is a dead end.

Thanks anyway,

Brooks V

[andrew_4619]

Well that is a couple of avenues closed

did you call selectobject to bring the brush unto the current device context? Posting some code might shed some light....

[Steven_L_Intel1]

Does your callback routine include !DEC$ ATTRIBUTES STDCALL? On IA-32, all Windows callbacks must be STDCALL. (Add REFERENCE if you want that, and include the same directive where the callback routine is declared for use in the call.

Also, check to see if you made the same mistake I made once upon a time.

[Brooks_Van_Horn]

The program was generated by the SDI code wizard. It is:

integer*4 function WinMainProc(hMain, message, wParam, lParam)
    !DEC$ ATTRIBUTES STDCALL, ALIAS : 'WinMainProc' :: WinMainProc

No Win32 but I'm using X64 settings/

Brooks V

[Brooks_Van_Horn]

    case (WM_PAINT)
    
         if (last == -1) Then
            hDC = GetDC(hWndMain)
            type *, 'WinMainProc:: WM_PAINT    hDC = ', hDC
            hOldFont = SelectObject(hDC,hMyFont12)
         end if
    
       if ((last == myOption) .or. (maxx == 0)) Then
          WinMainProc = 0
          return
       End If
       type *,  'WinMainProc:: WM_PAINT  Entering'

!      last = myOption
       if (hDC == NULL) Then
          type *, 'WinMainProc:: Cannot get hDC in WM_PAINT'
          WinMainProc = 0
          return
       End If
       nx = Rectxy%right - Rectxy%left
       ny = Rectxy%bottom - Rectxy%top
       type *, 'WinMainProc:: in WM_PAINT with nx, ny =', nx, ny
       if ((rectp%bottom /= 0) .and. (hBrush /= NULL)) Then
!          iret = FillRect ( hDC, rectp, hBrush)
       end if

Debug output after commenting the FillRect call out.

 Creating MainWindow
 WinMainProc:: WM_CREATE   Entering
 WinMainProc:: WM_CREATE  hPen =               28311575
 WinMainProc:: WM_CREATE  hBrush =               26214416
 WinMainProc:: WM_CREATE  hMyFont12 =              302655804
 WinMainProc:: WM_CREATE  hMyFont16 =            -1039523558
 WinMainProc:: WM_CREATE  hMyFont20 =             -284546895
 WinMainProc:: WM_CREATE  hMyFont24 =             1493837148
 WinMainProc:: WM_CREATE  hMyFont36 =             1510611582
 WinMainProc:: WM_CREATE   Leaving
 >>>>>>>>   WinMain Showing window
 WinMainProc:: WM_SIZE   Entering
 WinMainProc:: WM_SIZE   Leaving
 Beginning Dialog processing
 SetUpMyDlg:: DlgSetSub(IDD_PMAIN) RC =  T
 SetUpMyDlg:: DlgSetSub(IDC_FIT) RC =  T
 SetUpMyDlg:: DlgSetSub(IDC_SAMP) RC =  T
 SetUpMyDlg:: DlgSetSub(IDC_PCTYPE) RC =  T
 SetUpMyDlg:: CheckBoxDisabled(IDC_RAND) RC =  T
 SetUpMyDlg:: CheckBoxDisabled(IDC_SAVE) RC =  T
 SetUpMyDlg:: EditBoxChanged(IDC_RSSIZE) RC =  F
 SetUpMyDlg:: LabelChanged(IDC_RSLAB) RC =  T
 SetUpMyDlg:: EditboxDisAbled(IDC_FNAME) RC =  T
 SetUpMyDlg:: LabelDisAbled(IDC_FNAME) RC =  T
 SetUpMyDlg:: DlgModeless RC =  T
 SetUpMyDlg:: DlgSET(IDC_PCTYPE) RC =  T
 SetUpMyDlg:: DlgSET(IDC_MYSPIN) RC =  T
 SetUpMyDlg:: CheckRadioButton[Set](IDC_CENTRAL) RC =  T
 SetUpMyDlg:: DlgSetInt(IDC_MYSPIN,0,RangeMin) RC =  T
 SetUpMyDlg:: DlgSetInt(IDC_MYSPINL,8,RangeMax) RC =  T
 SetUpMyDlg:: DlgSrtInt(IDC_MYSPIN,0,Position) RC =  T
 SetUpMyDlg:: SetDlgItemText(IDC_PCTYPE,myBuffer) RC =  T
 SetUpMyDlg:: SetDlgItem(IDC_M1) RC =  T
 SetUpMyDlg:: SetDlgItem(IDC_M2) RC =  T
 SetUpMyDlg:: SetDlgItem(IDC_M3) RC =  T
 SetUpMyDlg:: SetDlgItem(IDC_M4) RC =  T
 SetUpMyDlg:: RadioChanged(IDC_STATISTICS) RC =  T
 SetUpMyDlg:: RadioChanged(IDC_PDF) RC =  T
 SetUpMyDlg:: RadioChanged(IDC_CDF) RC =  T
 SetUpMyDlg:: RadioChanged(IDC_HIST) RC =  T
 SetUpMyDlg:: RadioChanged(IDC_MORESTAT) RC =  T
 Dialog is up and running T
 Maxx, Maxy =         1735         996
 RectDialog (L,T,R,B)  =            0           0         184         997
 RectParent (L,T,R,B)  =          184           0        1736         997
 RectGeneral (L,T,R,B) =          194          10        1726         987
 RectDrawing (L,T,R,B) =           60          60        1676         937
 WinMainProc:: WM_PAINT    hDC =            -2113854287
 WinMainProc:: WM_PAINT  Entering
 WinMainProc:: in WM_PAINT with nx, ny =        1616         877
 WinMainProc:: WM_PAINT   Leaving
 WinMainProc::  WM_MOUSEMOVE  ==>
 Mouse at   618   99

@@@@@@@@@@@@@@@@@@@@@ I don't see why I needed to put the hBrush into the hDC with SelectObject because I'm sending the hBrush to the hDC in the FillRect call.

[IanH]

No pair of BeginPaint/EndPaint calls?

[Brooks_Van_Horn]

Correct. This is not Windows 3.1 anymore. There is no good reason to get a DC for a few things and then release it immediately. I am running a x64 application on an x64 OS with 32 GB of RAM.

Brooks V

[andrew_4619]

In all cases, an application can draw in a window as soon as it is created. To draw in the window, the application must first retrieve a handle to a display device context for the window. Ideally, an application carries out most of its drawing operations during the processing of WM_PAINT messages. In this case, the application retrieves a display device context by calling the BeginPaint function. If an application draws at any other time, such as from within WinMain or during the processing of keyboard or mouse messages, it calls the GetDC or GetDCEx function to retrieve the display DC.

I don't believe the begin/end paint call are optional. But I may be wrong.......

[Brooks_Van_Horn]

I can and do draw both text and graphics to my window withoug the paint structures.

Brooks V

[IanH]

The Begin/EndPaint pair updates windows internal data structures that track things such as the clipping region associated with the visible extent of the window and the update rectangle.  Getting a DC, and the ability to do drawing into a DC at arbitrary times, is somewhat incidental to this.  Certainly for versions of Windows <= Windows XP (so including versions well past Windows 3.1) failure to call that pair appropriately in a WM_PAINT message (or otherwise update the data structures) will result in strangeness.  I wouldn't regard it as optional.

[andrew_4619]

.... you normally get a paint as part of the region is invalidated. If you don't Begin/EndPaint  that itch doesn't get scratched and windows will keep throwing WM_PAINT messages.....

and I second Ian's words of wisdom.