Why the loadBMPImage produce error after the first time?

Posted by Legacy on 04/28/2000 12:00am

Originally posted by: Ricky Chow

I just use the loadBMPImage function to load the BMP and store the result in two member variables m_originalPicture (CBitmap) and m_originalPicturePalette (CPalette). For the first time, it works. However, debug assertion fail occurs at the second time. Why? My code for open & draw the BMP is as follow :

void CFaceDetectionDlg::OnFileOpen() 

{

	char FileName[500], FileTitle[100];

	OPENFILENAME openInformation;

	FileName[0] = '\0';

	memset (&openInformation, 0, sizeof(OPENFILENAME));

	openInformation.lStructSize			= sizeof(OPENFILENAME);

	openInformation.hwndOwner			= NULL;

	openInformation.hInstance			= NULL;

	openInformation.lpstrFilter			= TEXT("Bitmap files *.bmp\0*.bmp\0All Files *.*\0*.*\0\0");

	openInformation.lpstrCustomFilter	= NULL;

	openInformation.nMaxCustFilter		= 0;

	openInformation.nFilterIndex		= 1;

	openInformation.lpstrFile			= FileName;

	openInformation.nMaxFile			= 500;

	openInformation.lpstrFileTitle		= FileTitle;

	openInformation.nMaxFileTitle		= 99;

	openInformation.lpstrInitialDir		= NULL;

	openInformation.lpstrTitle			= "Open BMP File";

	openInformation.Flags				= OFN_FILEMUSTEXIST;

	openInformation.lpstrDefExt			= "BMP";

	openInformation.lCustData			= NULL;

	openInformation.lpfnHook			= NULL;

	openInformation.lpTemplateName		= NULL;

	GetOpenFileName (&openInformation);

	LoadBMPImage (FileName, m_originalPicture, &m_originalPicturePalette);

	// Create a memory DC compatible with the paint DC

	CDC memDC;

	CClientDC dc(this);

	

	memDC.CreateCompatibleDC (&dc);

	memDC.SelectObject (m_originalPicture);

	// The variable bitmap is a CBitmap object

	BITMAP bm;

	m_originalPicture.GetBitmap( &bm );

	dc.StretchBlt (20, 60, 250, 250, &memDC, 0, 0, bm.bmWidth, bm.bmHeight, SRCCOPY);

	memDC.DeleteDC ();

}

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the Load function does not work in VC6/W2k

Posted by Legacy on 07/11/1999 12:00am

Originally posted by: Ronen Magid

The section in the load bitmap method fails in this line:

HBITMAP hBmp = CreateDIBitmap(...............

it returns a HBITMAP which is null and therefore the
"attach" which follows it asserts....

The bitmap im trying to load is "healthy".

any solutions ?

Ronen

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Gaining access to the pixels array

Posted by Legacy on 05/31/1999 12:00am

Originally posted by: Marius Alexandru

How can i gain access to modify the pixel array of a bitmap (object)

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pls give an example of using

Posted by Legacy on 04/30/1999 12:00am

Originally posted by: Windy

I am a beginner of VC++, and I want to use these codes to
realize opening,loading and displaying a BMP file in a MDI
application.But I don't know how to use these codes,can you
help me and give me an example of using?

Thanks a lot,

Windy

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Bitmap

Posted by Legacy on 04/23/1999 12:00am

Originally posted by: Jeremy Bake

trying ot use this function I found that although you passed in a CBitmap object it never got referenced in
the function.  I found by changing the end of te function to:



...

	if( pOldPalette )		

		dc.SelectPalette( pOldPalette, FALSE ); 

	::GlobalFree(hDIB);

	bitmap.Attach(hBmp);   //this is all that's new

	return TRUE;

}



that it now worked perfectly.

	 RetroActive

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HANDLE to a pre-existing bitmap

Posted by Legacy on 02/24/1999 12:00am

Originally posted by: Michael Fountain

This load bitmap from bmp file code is great, but some of your other
examples (fade to gray ect.)pass a HANDLE Hdib. How do you get the HANDLE for the bitmap you just loaded from a bmp file?

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