bitmaps & regions [modified]

[zqueezy]

hey folks, I've got a little snippet I wanna use to do a splash screen from a mask-image (2-bit image). well... it doesn't work

CBitmap bg_Image; // create Image
bg_Image.LoadBitmap(IDB_BITMAP1); // load from resource

BITMAP bBitmap;
bg_Image.GetBitmap(&bBitmap); // load bitmap data

BYTE *pBuffer = new BYTE[bBitmap.bmWidth * bBitmap.bmHeight];

bg_Image.GetBitmapBits(bBitmap.bmHeight*bBitmap.bmWidth, pBuffer);

CRgn newRegion; // new region for dialog
newRegion.CreateRectRgn(0,0,0,0); // creat empty region

CRgn tmpRgn; // temporary region
for (int y=1; y< bBitmap.bmHeight; ++y)
{
for (int x=1; x < bBitmap.bmWidth; ++x)
{
BYTE c = pBuffer[(y)*bBitmap.bmWidth + x];
if (c == 255) // white
{
tmpRgn.DeleteObject(); // clear out region
tmpRgn.CreateRectRgn(x,y,x+1,y+1);
newRegion.CombineRgn(&newRegion, &tmpRgn, RGN_OR);
}

}

}
this->SetWindowRgn(newRegion, true);

delete [] pBuffer;

The result is nothing near what I expected... some ragged & jagged dialog. when I set a breakpoint on "tmpRgn.CreateRectRgn(x,y,x+1,y+1);" I find that the x and y of the for-loop is not what it should be in the image!!! any hints on how to do my splash-screen? thx in advance zqueezy -- modified at 20:58 Thursday 6th September, 2007

[Mark Salsbery]

All the code looks like it's for 8-bit images only (and assumes a WORD aligned width). If the source bitmap is not 8-bitsperpixel, then you need to use bBitmap.bmWidthBytes instead of bBitmap.bmWidth when calculating array size and offset of pixel  in buffer. Plus, if it's < 8 bpp, you need to mask out the appropriate bits to match the color. Mark

Mark Salsbery Microsoft MVP - Visual C++ :java:

[zqueezy]

so for anybody who's intrested and for the sake of completeness:

BOOL CMeineFormDlg::OnInitDialog()
{
CDialog::OnInitDialog();

// Symbol für dieses Dialogfeld festlegen. Wird automatisch erledigt
//  wenn das Hauptfenster der Anwendung kein Dialogfeld ist
SetIcon(m\_hIcon, TRUE);					// Großes Symbol verwenden
SetIcon(m\_hIcon, FALSE);				// Kleines Symbol verwenden

// TODO: Hier zusätzliche Initialisierung einfügen

CBitmap bg\_Image;						// Bild erstellen
bg\_Image.LoadBitmap(IDB\_BITMAP1);		// Bild aus Resource laden

BITMAP bBitmap;							// Damit man auf die Daten des Bitmap zugreifen kann
bg\_Image.GetBitmap(&bBitmap);			// Daten reinladen aus dem CBitmap

int  iByteSize = bBitmap.bmWidthBytes \* bBitmap.bmHeight \* (bBitmap.bmBitsPixel/8);
BYTE \*pBuffer = new BYTE\[iByteSize\];

bg\_Image.GetBitmapBits(iByteSize, pBuffer);

CRgn    newRgn;							// Eine neue Region für den Dialog
newRgn.CreateRectRgn(0,0,0,0);

CRgn	tmpRgn;							// Eine Temporäre Region

int iOffset = bBitmap.bmBitsPixel/8;
int r,g,b,c;
for (int y=0; y< bBitmap.bmHeight; ++y)
{
	for (int x=0; x < bBitmap.bmWidth; ++x)
	{
		c = y\*bBitmap.bmWidthBytes + x\*iOffset;
		r = pBuffer\[c+2\];
		g = pBuffer\[c+1\];
		b = pBuffer\[c\];

		if (r == 255 && g == 255 && b == 255)					// weiß
		{
			tmpRgn.DeleteObject();								// Die Region erstmal leer machen
			tmpRgn.CreateRectRgn(x,y,x+1,y+1);
			newRgn.CombineRgn(&newRgn, &tmpRgn, RGN\_OR);
		}
	}
}
this->SetWindowRgn(newRgn, true);
delete \[\] pBuffer;


return TRUE;  // Geben Sie TRUE zurück, außer ein Steuerelement soll den Fokus erhalten

}

[Mark Salsbery]

zqueezy wrote:

int iByteSize = bBitmap.bmWidthBytes * bBitmap.bmHeight * (bBitmap.bmBitsPixel/8);

...as long as you only use bitmaps witha format >= 8 bitsperpixel :) Mark

Mark Salsbery Microsoft MVP - Visual C++ :java: