实现背景颜色的渐变效果

如果只是实现水平或垂直方向的背景色渐变，只需重载OnEraseBkgnd函数，具体代码如下：CDialog::OnEraseBkgnd(pDC);

CRect rect;
GetClientRect(&rect);

int r1=127,g1=127,b1=56; //Any start color
int r2=5,g2=55,b2=165; //Any stop color

for(int i=0;i<rect.Width();i++) //如果是垂直方向则rect.Height(),下同
{
int r,g,b;
r = r1 + (i * (r2-r1) / rect.Width());
g = g1 + (i * (g2-g1) / rect.Width());
b = b1 + (i * (b2-b1) / rect.Width());
pDC->FillSolidRect(i,0,1,rect.Height(),RGB(r,g,b));
}

return true;

如果要实现倾斜的渐变，需要加一函数,同时在OnInitDialog中调用

CDialog::OnEraseBkgnd(pDC);

CRect rect;
GetClientRect(&rect);

CDC dc2;
dc2.CreateCompatibleDC(pDC);
CBitmap *oldbmap=dc2.SelectObject(&m_bitmap);

/*We copy the bitmap into the DC*/
pDC->BitBlt(0,0,rect.Width(),rect.Height(),&dc2,0,0,SRCCOPY);
dc2.SelectObject(oldbmap);

return true;

void CYourClassName::MakeBitmap()
{
CPaintDC dc(this);
CRect rect;
GetClientRect(&rect);

int r1=245,g1=190,b1=240;
int r2=130,g2=0,b2=0;

int x1=0,y1=0;
int x2=0,y2=0;

CDC dc2;
dc2.CreateCompatibleDC(&dc);

if(m_bitmap.m_hObject)
m_bitmap.DeleteObject();
m_bitmap.CreateCompatibleBitmap(&dc,rect.Width(),
rect.Height());

CBitmap *oldbmap=dc2.SelectObject(&m_bitmap);

while(x1 < rect.Width() && y1 < rect.Height())
{
if(y1 < rect.Height()-1)
y1++;
else
x1++;

if(x2 < rect.Width()-1)
x2++;
else
y2++;

int r,g,b;
int i = x1+y1;
r = r1 + (i * (r2-r1) / (rect.Width()+rect.Height()));
g = g1 + (i * (g2-g1) / (rect.Width()+rect.Height()));
b = b1 + (i * (b2-b1) / (rect.Width()+rect.Height()));

CPen p(PS_SOLID,1,RGB(r,g,b));
CPen *oldpen = dc2.SelectObject(&p);

dc2.MoveTo(x1,y1);
dc2.LineTo(x2,y2);

dc2.SelectObject(oldpen);
}

dc2.SelectObject(oldbmap);

}