MFC 绘制移动小球问题

Question

本帖最后由 td1442911376 于 2013-02-27 22:05:19 编辑

Answer 1

OnPaint()
CDC *pDC =GetDC();
    CBrush brushColor(RGB(255,255,0));//填充的颜色
    CPen penColor;
    penColor.CreatePen(PS_SOLID,1,RGB(0,64,128));//边框颜色
    pDC->SelectObject(penColor);
    pDC->SelectObject(brushColor);
 
    OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags) 
CPoint p(b.x,b.y);
myEllipse(pDC,p,r);
    brushColor.DeleteObject();
   penColor.DeleteObject();
  ReleaseDC(pDC);
myEllipse(pDC,p,r);void myEllipse(CDC *dc, POINT ptCenter, UINT uRadius)
{
POINT ptLeftTop, ptRightBottom;
 
ptLeftTop.x = ptCenter.x - uRadius;
ptLeftTop.y = ptCenter.y - uRadius;
ptRightBottom.x = ptCenter.x + uRadius;
ptRightBottom.y = ptCenter.y + uRadius;
 
Ellipse(*dc, ptLeftTop.x, ptLeftTop.y,
ptRightBottom.x, ptRightBottom.y);
}void CDRAWDlg::OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags) 
{
    // TODO: Add your message handler code here and/or call default
     
    CDialog::OnKeyDown(nChar, nRepCnt, nFlags);
 
  switch(nChar)
 
       {
 
       case VK_LEFT://按下左键
 
              b.x=b.x-10;
              
UpdateWindow();
 
              break;    
 
       case VK_RIGHT://按下右键
               b.x=b.x+10;
            UpdateWindow();
 
              break;
 
       case VK_UP://按下上键
 
               b.y=b.y+10;
UpdateWindow();
 
              break;
 
       case VK_DOWN:// 按下下键
 
              b.y=b.y-10;
UpdateWindow();
 
              break;
 
       default:
 
              break;
 
       }
 
}

Answer 2

int nPosX,nPosY;
void CCMoveBallView::OnDraw(CDC* pDC)
{
CCMoveBallDoc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
if (!pDoc)
return;

CBrush bush(RGB(255,0,0));
pDC->SelectObject(bush);
CPen pen(PS_SOLID,2,RGB(255,0,0));
pDC->SelectObject(pen);
pDC->Ellipse(CRect(nPosX,nPosY,nPosX+20,nPosY+20));
}void CCMoveBallView::OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags)
{
switch(nChar)
{
case VK_UP:
 nPosY -=10;
 break;
case VK_DOWN:
 nPosY +=10;
 break;
case VK_LEFT:
nPosX -=10;
 break;
case VK_RIGHT:
nPosX +=10;
break;
}
this->Invalidate(); CView::OnKeyDown(nChar, nRepCnt, nFlags);
}这个是在当文档中实现的你可以参考！！

Answer 3

UpdateWindow 是你自己写的？