Changing pixel color on a bitmap

vcplusplus

I have a button on my CFormView with a bitmap. How can I change the color of each individual pixel in the bitmap?

Ryan Binns

dwccgc wrote: How can I change the color of each individual pixel in the bitmap? Select it into a device context and use SetPixel() or SetPixelV(), the latter being the fastest.

Ryan

"Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

vcplusplus

I need to get the current color before I use SetPixel(..), but I cannot get GetPixel() to work. pDc->GetPixel() returns -1. Maybe I am missing something. Note: m_ExitButtonCtrl is of type CButton. hbmButtonExit is of type HBITMAP.

void CMyFormView::OnInitialUpdate()
{
CFormView::OnInitialUpdate();

// Load BitMap
hbmButtonExit = ::LoadBitmap(AfxGetInstanceHandle(), MAKEINTRESOURCE(IDB\_BUTTON\_EXIT));
if (hbmButtonExit != NULL)
{
   m\_ExitButtonCtrl.SetBitmap(hbmButtonExit);
   CDC \*pDc = m\_ExitButtonCtrl.GetDC();
   if (pDc != NULL)
   {
       for (INT nX = 0; nX < 69; nX++)
       {
           for (INT nY = 0; nY < 47; nY++)
           {
              COLORREF OrgColor = **pDc->GetPixel(nX, nY);**
           }
       }
   }
}
return;

}

Ryan Binns

You need to select the bitmap into a device context.

void CMyFormView::OnInitialUpdate()
{
CFormView::OnInitialUpdate();
hbmButtonExit = ::LoadBitmap(AfxGetInstanceHandle(), MAKEINTRESOURCE(IDB_BUTTON_EXIT));
if (hbmButtonExit != NULL)
{
CClientDC dc(this);
CDC memDC;
memDC.CreateCompatibleDC(&dc);
CBitmap *pBitmap = memDC.SelectObject(CBitmap::FromHandle(hbmButtonExit));
for (INT nX = 0; nX < 69; nX++)
{
for (INT nY = 0; nY < 47; nY++)
{
COLORREF OrgColor = memDC.GetPixel(nX, nY);
// Do whatever else here
}
}
memDC.SelectObject(pBitmap);
m_ExitButtonCtrl.SetBitmap(hbmButtonExit);
}
}

Ryan

"Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

vcplusplus

Thanks for the help.:)

Ryan Binns

You're welcome :)

Ryan

"Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"