CODEWITHSUNDEEP
c#bitmapgdi+hbitmap
user646265
user646265

Reputation: 1031

Generic GDI+ Error when saving hBitmap as Bitmap

I am writing my own DIB/BMP decoder (I know there are already others, but I'm learning about image processing) and I have managed to store the pixels in a pointer and get the relevant dimensions for writing a hBitmap, but this error keeps turning up:

Generic Error Occured in GDI+.

Below is the stack trace and the code:

at System.Drawing.Image.FromHbitmap(IntPtr hbitmap, IntPtr hpalette)
at System.Drawing.Image.FromHbitmap(IntPtr hbitmap)
at pcx_reader.bmp.BitmapFromPCXBits(Int32 height, Int32 width, Int32 numplanes, Int32 bpp, IntPtr pixels)
at pcx_reader.MainWindow.button1_Click(Object sender, RoutedEventArgs e)
at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
at System.Windows.UIElement.RaiseEvent(RoutedEventArgs e)
at System.Windows.Controls.MenuItem.InvokeClickAfterRender(Object arg)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
at System.Windows.Threading.DispatcherOperation.InvokeImpl()
at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state)
at System.Threading.ExecutionContext.runTryCode(Object userData)
at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Windows.Threading.DispatcherOperation.Invoke()
at System.Windows.Threading.Dispatcher.ProcessQueue()
at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
at System.Windows.Threading.Dispatcher.InvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
at System.Windows.Threading.Dispatcher.Run()
at System.Windows.Application.RunDispatcher(Object ignore)
at System.Windows.Application.RunInternal(Window window)
at System.Windows.Application.Run(Window window)
at System.Windows.Application.Run()
at pcx_reader.App.Main()
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()

Code:

    public Bitmap BitmapFromPCXBits(int height, int width, int numplanes, int bpp, IntPtr pixels)
    {
        IntPtr hDc = CreateCompatibleDC(IntPtr.Zero);
        IntPtr hBitmap = IntPtr.Zero;
        IntPtr hOldBitmap = IntPtr.Zero;

        hBitmap = CreateBitmap(width, height, (uint)numplanes, (uint)bpp, pixels);
        hOldBitmap = SelectObject(hDc, hBitmap);

        System.Drawing.Bitmap bmp = System.Drawing.Bitmap.FromHbitmap(hBitmap);
        //Bitmap bmp = new Bitmap(width, height, stride, System.Drawing.Imaging.PixelFormat.Format1bppIndexed, pixels);

        DeleteObject(SelectObject(hDc, hOldBitmap));

        DeleteDC(hDc);

        return bmp;
    }

I have no idea what's wrong, but I use a similar function for PCX files and they fail with all but monochrome images, which render fine. If anyone can help, I' be very thankful.

Upvotes: 0

Views: 2044

Answers (1)

Adam
Adam

Reputation: 637

It is hard to tell without knowing what input parametes you have in your call...

Anyway a couple of things to try:

  • check the return value from CreateBitmap() !
  • Make sure the number of bitplanes is right

  • use the Bitmap constructor instead (with the the GDI+ enum for Bitmap format, if the number of planes is known you may not need to pass it as a parameter)

    // This works in C++

    HDC hOff = ::CreateCompatibleDC( NULL );

    Bitmap oDaBigOne( g_iWidth, g_iHeight, PixelFormat32bppARGB );

    HBITMAP hBMit = NULL;

    Color oCol( 0, 0, 0, 0 );

    oDaBigOne.GetHBITMAP( oCol, &hBMit );

    HGDIOBJ hSave = ::SelectObject( hOff, hBMit );

Upvotes: 0

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