Painting a Gradient back ground
Posted by: Neel Aakash on: June 8, 2009
- In: MFC
- Leave a Comment
Here’s a sample which draws background of a dialog with gradient colors.
BOOL CMyDlg::OnEraseBkgnd(CDC* pDC)
{
CRect rect;
GetClientRect(&rect);
TRIVERTEX vert[4] = {
{ rect.left, rect.top, 0xff00, 0xff00, 0xff00, 0 },
{ rect.right, rect.top, 0, 0xff00, 0xff00, 0 },
{ rect.right, rect.bottom, 0xff00, 0, 0xff00, 0 },
{ rect.left, rect.bottom, 0xff00, 0xff00, 0, 0 }
};
GRADIENT_TRIANGLE grad[2] = {
{ 0, 1, 2 },
{ 0, 2, 3 }
};
::GradientFill( pDC->m_hDC, vert, 4, grad, 2, GRADIENT_FILL_TRIANGLE );
return TRUE;
}
void CMyDlg::OnSize(UINT nType, int cx, int cy)
{
// To ensure the background of the whole dialog is re-drawn
Invalidate();
CDialog::OnSize(nType, cx, cy);
}
Replaces a color with a fill color in a given area of a Device Context
Posted by: Neel Aakash on: May 28, 2009
- In: MFC
- Leave a Comment
//! Replaces a color with a fill color in a given area of a
//! Device Context
//!
//! \param hDC : Specifies the Device Context
//! \param rcReplaceArea : Specifies the portion of the DC area
//! to apply the replace operation
//! \param clrColorReplace : Specifies the color to be replaced
//! \param clrColorFill : Specifies the fill color
void ReplaceColor(HDC hDC, CRect rcReplaceArea, COLORREF clrColorReplace, COLORREF clrColorFill)
{
CDC* pDC = CDC::FromHandle(hDC);
CPoint pt = rcReplaceArea.TopLeft();
CDC memDCMonoChrome;
memDCMonoChrome.CreateCompatibleDC(pDC);
CBitmap bmpMonoChrome;
bmpMonoChrome.CreateCompatibleBitmap(&memDCMonoChrome,
rcReplaceArea.Width(), rcReplaceArea.Height());
CBitmap* pOldMonoBitmap =
memDCMonoChrome.SelectObject(&bmpMonoChrome);
COLORREF nOldBkColor = pDC->SetBkColor(clrColorReplace);
// BLT to mono dc so that mask color will have 1 set and the other colors 0
memDCMonoChrome.BitBlt(0, 0, rcReplaceArea.Width(),
rcReplaceArea.Height(), pDC, pt.x, pt.y, SRCCOPY);
CDC memDC;
memDC.CreateCompatibleDC(pDC);
CBitmap bmp;
bmp.CreateCompatibleBitmap(pDC, rcReplaceArea.Width(),
rcReplaceArea.Height());
CBitmap* pOldBitmap = memDC.SelectObject(&bmp);
COLORREF nOldMemDCBkColor = memDC.SetBkColor(clrColorFill);
COLORREF nOldMemDCTextColor =
memDC.SetTextColor(RGB(255, 255, 255));
// BLT to mem DC so that the monochrome white is set to fill color and the
// monochrome black is set to white
memDC.BitBlt(0, 0, rcReplaceArea.Width(), rcReplaceArea.Height(),
&memDCMonoChrome, 0, 0, SRCCOPY);
// AND pDC with mem dc so that the replace color part is blackened out and
// all other colors remains same
pDC->BitBlt(pt.x, pt.y, rcReplaceArea.Width(), rcReplaceArea.Height(),
&memDC, 0, 0, SRCAND);
memDC.SetTextColor(RGB(0, 0, 0));
// BLT to mem DC so that the monochrome white is set to fill color and the
// monochrome black is set to black
memDC.BitBlt(0, 0, rcReplaceArea.Width(), rcReplaceArea.Height(),
&memDCMonoChrome, 0, 0, SRCCOPY);
// OR pDC with mem dc so that all colors remains as they where except the
// blackened out (replace color) part receives the fill color
pDC->BitBlt(pt.x, pt.y, rcReplaceArea.Width(), rcReplaceArea.Height(),
&memDC, 0, 0, SRCPAINT);
// Set the original values back
memDC.SetTextColor(nOldMemDCTextColor);
memDC.SetBkColor(nOldMemDCBkColor);
pDC->SetBkColor(nOldBkColor);
// Set the original bitmaps back
memDCMonoChrome.SelectObject(pOldMonoBitmap);
memDC.SelectObject(pOldBitmap);
}
Sequence of messages sent on Double Click Event
Posted by: Neel Aakash on: May 19, 2009
1. LButtonDown
2. LButtonUp
3. LButtonDblClick
4. LButtonUp
Wild-Card Comparison
Posted by: Neel Aakash on: May 13, 2009
- In: C/C++
- Leave a Comment
Sometimes we have needed to compare a Wild-Card string in a given string. Here is a handy function for doing this:
int WildCmp(const TCHAR* wild, const TCHAR* string)
{
const TCHAR *cp = NULL, *mp = NULL;
while ((*string) && (*wild != ‘*’))
{
if ((*wild != *string) && (*wild != ‘?’))
{
return 0;
}
wild++;
string++;
}
while (*string)
{
if (*wild == ‘*’)
{
if (!*++wild)
{
return 1;
}
mp = wild;
cp = string+1;
}
else if ((*wild == *string) || (*wild == ‘?’))
{
wild++;
string++;
}
else
{
wild = mp;
string = cp++;
}
}
while (*wild == ‘*’)
{
wild++;
}
return !*wild;
}
Draw vertically centered multi-line text in a given rectangle
Posted by: Neel Aakash on: April 22, 2009
- In: MFC
- Leave a Comment
DT_WORDBREAK and DT_VCENTER don’t work together. So here is an alternative:
void CEMCHotButton::DrawCaption (CDC* pDC, LPDRAWITEMSTRUCT
lpDrawItemStruct, CRect& rectCaption, DWORD dwFormat)
{
// Get caption text
CString strCaption;
GetWindowText (strCaption);
if(!strCaption.IsEmpty())
{
if((GetStyle() & BS_MULTILINE) == BS_MULTILINE)
{
dwFormat &= ~DT_SINGLELINE;
dwFormat &= ~DT_VCENTER;
dwFormat |= DT_WORDBREAK;
RECT rct = rectCaption;
int height = ::DrawText(pDC->m_hDC, (LPCTSTR) strCaption, strCaption.GetLength(), &rct, DT_CALCRECT | DT_WORDBREAK);
rectCaption.top = rectCaption.CenterPoint().y – height / 2;
::DrawTextEx (pDC->m_hDC, strCaption.GetBuffer(0),
strCaption.GetLength(), &rectCaption,
dwFormat, NULL);
}
}
}
