中利用設(shè)計(jì)繪圖程序初步呢

首先我們說(shuō)下通過(guò)鼠標(biāo)的移動(dòng)來(lái)繪制直線。

這里要捕獲到鼠標(biāo)的兩個(gè)消息：WM_LBUTTONDOWN, WM_LBUTTONUP。響應(yīng)WM_LBUTTONDOWN消息記錄直線的起始點(diǎn)，響應(yīng)WM_LBUTTONUP消息記錄直線的終點(diǎn)并繪制直線。

好了，我們看看怎么響應(yīng)。

void CDrawView::OnLButtonDown(UINT nFlags, CPoint point)

{

//MessageBox(\"Left Button Clicks DrawView\");

m_ptOrigin = point ; //這里先定義了一個(gè)內(nèi)部變量保存直線的起始點(diǎn)

CView::OnLButtonDown(nFlags, point);

}

下面看看響應(yīng)WM_LBUTTONUP消息記錄直線的終點(diǎn)并繪制直線。

//方法一

void CDrawView::OnLButtonUp(UINT nFlags, CPoint point)

{

HDC hdc;

hdc = ::GetDC(m_hWnd); //調(diào)用全局函數(shù)

MoveToEx(hdc,m_ptOrigin.x,m_ptOrigin.y,0);

LineTo(hdc,point.x,point.y);

::ReleaseDC(m_hWnd,hdc);

CView::OnLButtonUp(nFlags, point);

}

//方法二

void CDrawView::OnLButtonUp(UINT nFlags, CPoint point)

{

CDC *pDC = GetDC();

pDC-MoveTo(m_ptOrigin);

pDC-LineTo(point);

ReleaseDC(pDC);

}

//方法三

void CDrawView::OnLButtonUp(UINT nFlags, CPoint point)

{

CClientDC dc(this) ; //CClientDC對(duì)象構(gòu)造的時(shí)候就調(diào)用了GetDC，析構(gòu)的時(shí)候調(diào)用

ReleaseDC ，只能訪問(wèn)客戶區(qū)

CClientDC dc(GetParent());

veTo(m_ptOrigin);

neTo(point);

}

//方法四

void CDrawView::OnLButtonUp(UINT nFlags, CPoint point)

{

CWindowDC dc(this) ; //CWindowDC可以訪問(wèn)客戶區(qū)和非客戶區(qū)

veTo(m_ptOrigin);

neTo(point);

}

void CDrawView::OnLButtonUp(UINT nFlags, CPoint point)

{

CWindowDC dc(GetDesktopWindow()) ; //現(xiàn)在可以訪問(wèn)桌面

veTo(m_ptOrigin);

neTo(point);

}

連續(xù)線繪圖：

思路：鼠標(biāo)移動(dòng)的信號(hào)被捕捉到，然后隨時(shí)響應(yīng)該信號(hào)，繪制圖線。

這里要設(shè)置一個(gè)BOOL變量 m_bDraw 來(lái)判斷是否鼠標(biāo)左鍵按下了。

//畫連續(xù)的線條

void CDrawView::OnMouseMove(UINT nFlags, CPoint point)

{

if ( m_bDraw )

{

CClientDC dc(this) ;

veTo(m_ptOrigin); //移動(dòng)到原來(lái)的點(diǎn)

neTo(point); //繪制直線

m_ptOrigin = point ; //將現(xiàn)在的點(diǎn)賦值給原來(lái)的坐標(biāo)，以便下次調(diào)用

}

CView::OnMouseMove(nFlags, point);

}

//改變畫筆的顏色

void CDrawView::OnMouseMove(UINT nFlags, CPoint point)

{

if ( m_bDraw )

{

CClientDC dc(this) ;

CPen pen( PS_SOLID , 1 , RGB(255,128,128) );

CPen *pOldPen = lectObject(pen);

veTo(m_ptOrigin);

neTo(point);

m_ptOrigin = point ;

lectObject(pOldPen);

}

CView::OnMouseMove(nFlags, point);

}

//畫扇型

void CDrawView::OnMouseMove(UINT nFlags, CPoint point)

{

if ( m_bDraw )

{

CClientDC dc(this) ;

CPen pen( PS_SOLID , 1 , RGB(255,128,128) );

CPen *pOldPen = lectObject(pen);

但由于F-86過(guò)于笨重 veTo(m_ptOrigin);

neTo(m_ptOld);

veTo(m_ptOrigin);

neTo(point);

m_ptOld = point ;

lectObject(pOldPen);

}

CView::OnMouseMove(nFlags, point);

}

//畫帶邊線的扇型

void CDrawView::OnMouseMove(UINT nFlags, CPoint point)

{

if ( m_bDraw )

{

CClientDC dc(this) ;

CPen pen( PS_SOLID , 1 , RGB(255,128,128) );

CPen *pOldPen = lectObject(pen);

veTo(m_ptOrigin);

neTo(m_ptOld);

veTo(m_ptOrigin);

neTo(point);

veTo(m_ptOld);

neTo(point);

m_ptOld = point ;

lectObject(pOldPen);

}

CView::OnMouseMove(nFlags, point);

}

//看看繪圖的模式設(shè)置方法

void CDrawView::OnMouseMove(UINT nFlags, CPoint point)

{

if ( m_bDraw )

{

CClientDC dc(this) ;

tROP2(R2_BLACK); //繪圖的模式設(shè)置,始終繪制黑色圖形

CPen pen( PS_SOLID , 1 , RGB(255,128,128) );

CPen *pOldPen = lectObject(pen);

veTo(m_ptOrigin);

neTo(m_ptOld);

veTo(m_ptOrigin);

neTo(point);

veTo(m_ptOld);

neTo(point);

m_ptOld = point ;

lectObject(pOldPen);

}

CView::OnMouseMove(nFlags, point);

}

到此，我們知道了一般地繪圖方法了。查看本文來(lái)源