MFC實例：圖形移動

案例7： 實際應用
實現點擊產生隨機大小、隨機顏色的球，如果左鍵按下產生的小球，按下過程當中小球上移，如果右鍵按下產生的小球，按下過程當中小球下移，可以保存、讀取。
運行截圖：

插入代碼以下：
定義要存儲的變量：（記得初始化）

class CBubbleUpDoc : public CDocument
{
// Attributes
public:
CRect BubbleRect[MAX];
int BubbleColor[MAX];
int m_Bubble;
...

修改Serialize函數實現數據存儲：

void CBubbleUpDoc::Serialize(CArchive& ar)
{
if (ar.IsStoring())
{
    // TODO: add storing code here
    ar<<m_Bubble;
    for (int i=0;i<m_Bubble;i++)
    ar << BubbleRect[i];
    for (i=0;i<m_Bubble;i++)
    ar << BubbleColor[i];
}
else
{
    // TODO: add loading code here
    ar>>m_Bubble;
    for (int i=0;i<m_Bubble;i++)
    ar >> BubbleRect[i];
    for (i=0;i<m_Bubble;i++)
    ar >> BubbleColor[i];
    }
}

修改OnDraw函數：

void CBubbleUpView::OnDraw(CDC* pDC)
{
    CBubbleUpDoc* pDoc = GetDocument();
    ASSERT_VALID(pDoc);
    CBrush BrushNew[MAX],*BrushOld;
    CPen PenNew,*PenOld;

    PenNew.CreatePen(0,1,RGB(0,0,0));
    PenOld = pDC->SelectObject(&PenNew);

    for (int i=0;i<pDoc->m_Bubble;i++)
    {
        switch (pDoc->BubbleColor[i])
        {
            case (1):
                BrushNew[i].CreateSolidBrush(RGB(255,0,0));
                BrushOld = pDC->SelectObject(&BrushNew[i]);
                break;
            case (2):
                BrushNew[i].CreateSolidBrush(RGB(0,255,0));
                BrushOld = pDC->SelectObject(&BrushNew[i]);
                break;
            case (3):
                BrushNew[i].CreateSolidBrush(RGB(0,0,255));
                BrushOld = pDC->SelectObject(&BrushNew[i]);
        }
    pDC->Ellipse(pDoc->BubbleRect[i]);
    }
    pDC->SelectObject(PenOld);
    pDC->SelectObject(BrushOld);
    // TODO: add draw code for native data here
}

添加的函數：

void CBubbleUpView::OnLButtonDown(UINT nFlags, CPoint point) 
{
CBubbleUpDoc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
// TODO: Add your message handler code here and/or call default
SetTimer(1,100,NULL);
if (pDoc->m_Bubble < MAX){
int color = rand()%3 +1;
pDoc->BubbleColor[pDoc->m_Bubble] = color;
int r = rand()%100 + 15;

CRect rect(point.x-r,point.y-r,point.x+r,point.y+r);
pDoc->BubbleRect[pDoc->m_Bubble] = rect;
pDoc->m_Bubble++;

pDoc->SetModifiedFlag();
InvalidateRect(rect,FALSE);}

CView::OnLButtonDown(nFlags, point);
}

void CBubbleUpView::OnLButtonUp(UINT nFlags, CPoint point) 
{
// TODO: Add your message handler code here and/or call default
KillTimer(1);
CView::OnLButtonUp(nFlags, point);
}


void CBubbleUpView::OnRButtonDown(UINT nFlags, CPoint point) 
{
CBubbleUpDoc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
// TODO: Add your message handler code here and/or call default
SetTimer(2,100,NULL);
if (pDoc->m_Bubble < MAX){
int color = rand()%3 +1;
pDoc->BubbleColor[pDoc->m_Bubble] = color;
int r = rand()%100 + 15;

CRect rect(point.x-r,point.y-r,point.x+r,point.y+r);
pDoc->BubbleRect[pDoc->m_Bubble] = rect;
pDoc->m_Bubble++;

pDoc->SetModifiedFlag();
InvalidateRect(rect,FALSE);}

CView::OnRButtonDown(nFlags, point);
}

void CBubbleUpView::OnRButtonUp(UINT nFlags, CPoint point) 
{
// TODO: Add your message handler code here and/or call default
KillTimer(2);
CView::OnRButtonUp(nFlags, point);
}

void CBubbleUpView::OnTimer(UINT nIDEvent) 
{
CBubbleUpDoc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
// TODO: Add your message handler code here and/or call default
if (nIDEvent==1){
CRect rect = pDoc->BubbleRect[pDoc->m_Bubble-1];
rect.top-=5;
pDoc->BubbleRect[pDoc->m_Bubble-1].top-=5;
pDoc->BubbleRect[pDoc->m_Bubble-1].bottom-=5;
pDoc->SetModifiedFlag();
InvalidateRect(rect,TRUE);
}else {
CRect rect = pDoc->BubbleRect[pDoc->m_Bubble-1];
rect.bottom+=5;
pDoc->BubbleRect[pDoc->m_Bubble-1].top+=5;
pDoc->BubbleRect[pDoc->m_Bubble-1].bottom+=5;
pDoc->SetModifiedFlag();
InvalidateRect(rect,TRUE);
}
CView::OnTimer(nIDEvent);
}

知識點：
1.畫刷不能用CreateSolidBrush（實心填塗）或者CreateHatchBrush（特殊填塗）來修改其性質（顏色、樣式）；
2.更新移動的矩形區域時記得刷新掉未移動的圖形殘留，即刷新區域比做圖區域要多出移動距離那麼長的一個矩形