GDI Debugger

The purpose of GDI Debugger, is to demonstrate how code can recognize, locate and
diagnose bugs, plus hopefully make recommendations or fix them. For now, it locates them
and occassionally gives advice.
 The GDI debugging wrappers trap calls to some Win32API functions which are related
to graphics. They test the parameters sent to them and log any errors they find.
A "final report" can also be generated.
This will hopefully be expanded to cover many other bug-prone programming categories.

---

To use:
    Make sure you don't have the "#Tools Off" statement anywhere, or you won't
    get a trace file.
                        *   *   *   *   *
    Place the following four lines before any other #Include statements:
%GdiDebug      = 1
#If %Def(%GdiDebug)
    %NOGDI      = 1
#EndIf
                        *   *   *   *   *
    Instead of #Include-ing "Win32API.inc" as usual, use the following conditionals.
    Note that "Win32API_DB.inc" is a file you'll have to prepare from a copy of
    "Win32API.inc" by REM-ing out the declares for the wrapped functions which aren't
    imported from GDI32.DLL. You'll be alerted to any errors in this when you try to
    compile because the Sub "VerifyWrappers" can't get CodePtrs to imported functions.

#If %Def(%GdiDebug)
    #Include "Win32API_DB.inc"
    #Include "GDI_Declares.inc" 'this contains declares for non-wrapped GDI functions
#Else
    #Include "Win32API.inc"
#EndIf

#If %Def(%GdiDebug)
    #Include "GDI_Debug.inc"    'this contains the wrappers
#EndIf
                        *   *   *   *   *
    Finally, place the following three lines just before "End Function" in WinMain:
#If %Def(%GdiDebug)
    GdiDebugFinalReport
#EndIf

---

Currently included wrappers:
    BeginPaint
    EndPaint
    CreateCompatibleBitmap
    CreateFont
    CreatePen
    CreateSolidBrush
    CreateCompatibleDC
    CreateDC
    DeleteDC
    GetDC
    ReleaseDC
    DeleteObject
    SelectObject
    SetROP2
    SetTextColor

    (Some of these were selected because they
    appeared in a project that needed testing)

---

What it does:
    GdiDebugger doesn't interfere with your program. Your Win32API calls are merely monitored
    and checked for: bad parameters, programming mistakes and errors returned by Windows.
                        *   *   *   *   *
    Shows error messages when the actual API calls fail.
                        *   *   *   *   *
    It verifies that all window handles are currently valid, and warns if the screen's
    window handle is used (it's okay, but sometimes it's done by mistake).
                        *   *   *   *   *
    It tracks all DC handles encountered to be sure they are valid and to be sure they are
    eventually released or deleted.
                        *   *   *   *   *
    It checks DC's for the existence of non-default objects selected into them when your
    program tries to release or delete them.
                        *   *   *   *   *
    It recognizes attempts to select a bitmap into more than one DC at a time.
                        *   *   *   *   *
    It alerts you to attempts to delete a window DC or to release a memory DC.
                        *   *   *   *   *
    It includes object type names ("pen", "font",...) with every comment about them, so you
    needn't keep track of them.
                        *   *   *   *   *
    Monitors the balancing of "BeginPaint" and "EndPaint" calls.
                        *   *   *   *   *
    It verifies that calls to "BeginPaint" and "EndPaint" are in response to %WM_PAINT messages
    (this is the recommended practice).
                        *   *   *   *   *
    When errors are found, the call stack is listed with parameters in HEX.
                        *   *   *   *   *
    When "WndProc" is found in a call stack, the messages are translated to their standard equate
    names. For example:  WNDPROC( &H0, &H2, &H0, &H0 )    %WM_DESTROY
    For this feature to work The equate: "$WndProc" must be set to the upper-cased name of your
    window's message handler, plus an opening parenthesis. For example: $WndProc = "WNDPROC("
                        *   *   *   *   *
    Window handle, DC handle and object handle values are checked to see if they could have been
    accidentally passed "ByRef" instead of "ByVal". This is done by checking against value ranges
    and making an API call to get the status of memory at the addresses.
                        *   *   *   *   *
    There's no need to change the names of the API calls in your code. The names of the calls in
    the API declares have been changed in GdiDebugger. The parameters are passed unmodified, to
    the actual Win32API imports.
                        *   *   *   *   *
    Shows a list of all the currently active wrappers. This feature will also help you guard
    against mistakes in configuring your #Includes, because otherwise, a declaration in the
    standard Win32API.inc could override it if it's not REMed out.
                        *   *   *   *   *
    Generates a "GdiDebugger Final Report", which includes:
    A "Window Handle Report", "Window DC Report", "Memory DC Report" and an "Object Creation
    and Deletion Report"
    These reports include:
    The total numbers of window handles, window DCs and memory DCs encountered.
    Lists of all the window handles, window DCs and memory DCs encountered.
    Undeleted objects.
                        *   *   *   *   *
    Lists the total numbers of calls to each wrapper.





The GDI Debugger source code is in the "gdidebug" folder of the CVS directory
Browse CVS
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Project Summary Page at SourceForge.net







This project is sponsored by TheirCorp
(formerly TheirWare Corporation)