多边形填充实验

实验目标:

1.窗口对用户"左按键"和"右按键"事件的响应

2.实现多边形填充

步骤:

1.运行VC6.0

2.创建工程Fill , (工程类型选择:MFC Wizard (.exe) )

3. 添加 "双击左键"和"单击右键"事件的消息响应

(1).选择菜单"View"->"class Wizard"

(2)在弹出的窗口里

classname: 选择CFillView

Messages: 分别选择 WM_LBUTTONDBLCLK , WM_RBUTTONDOWN

然后Add Function

4.修改代码:

(1) 修改fillview.h文件 :

在类的定义中,加入如下代码:

public:

CPoint spt[7];

void Floodfill(CPoint s_point, int f_color, int b_color) ;

(2)修改fillview.cpp文件

修改OnDraw,OnLButtonDblClk,OnRButtonDown的三个函数

加入一个函数: Floodfill

void CFillView::OnDraw(CDC* pDC)

{

CFillDoc* pDoc = GetDocument();

ASSERT_VALID(pDoc);

CPen newpen(PS_SOLID,1,RGB(255,0,0));

CPen *old=pDC->SelectObject(&newpen);

pDC->TextOut(20,20,"双击鼠标左键, 出现需填充的多边形");

pDC->TextOut(20,50,"进行填充, 需用鼠标右键, 单击多边形内一点, 作为开始填充的种子点");

pDC->SelectObject(old);

}

(2)void CFillView::OnLButtonDblClk(UINT nFlags, CPoint point)

{

// TODO: Add your message handler code here and/or call default

RedrawWindow();

CDC* pDC=GetDC();

CPen newpen(PS_SOLID,1,RGB(255,0,0));

CPen *old=pDC->SelectObject(&newpen);

//多边形各顶点的坐标

spt[0]=CPoint(100,100);

spt[1]=CPoint(300,100);

spt[2]=CPoint(250,250);

spt[3]=CPoint(100,250);

spt[4]=CPoint(150,200);

spt[5]=CPoint(90,180);

spt[6]=CPoint(150,150);

spt[7]=CPoint(100,100);

pDC->Polyline(spt,8); //画多边形
pDC->SelectObject(old);

ReleaseDC(pDC);

CView::OnLButtonDblClk(nFlags, point);

}

void CFillView::OnRButtonDown(UINT nFlags, CPoint point)

{

// TODO: Add your message handler code here and/or call default

CView::OnRButtonDown(nFlags, point);

int fill=RGB(0,255,0);

int boundary=RGB(255,0,0);

Floodfill(point, fill, boundary);
}

/*

s_point 为种子点

f_color是要填充的颜色, b_color是边界的颜色

*/

void CFillView::Floodfill(CPoint s_point, int f_color, int b_color)

{

CWindowDC dc (this);

int x,y,p0,pmin,pmax;

//求多边形的最大最小值

pmin=pmax=spt[0].y;

for(int i=1;i<8;i++)

{

if(spt[i].y<pmin) pmin=spt[i].y;

if(spt[i].y>pmax) pmax=spt[i].y;

}

x=s_point.x;

y=s_point.y;

for(;y<pmax;y++)

{

int current=dc.GetPixel(x,y);

while((current!=b_color)&&(current!=f_color))

{

dc.SetPixel(x,y,f_color);

x++;

current=dc.GetPixel(x,y);

}

x=s_point.x;

x--;

current=dc.GetPixel(x,y);

while((current!=b_color)&&(current!=f_color))

{

dc.SetPixel(x,y,f_color);

x--;

current=dc.GetPixel(x,y);

}

x=s_point.x;

}

x=s_point.x;

y=s_point.y-1;
for(;y>pmin+2;y--)

{

int current=dc.GetPixel(x,y);

while((current!=b_color)&&(current!=f_color))

{

dc.SetPixel(x,y,f_color);

x++;

current=dc.GetPixel(x,y);

}

x=s_point.x;

x--;

current=dc.GetPixel(x,y);

while((current!=b_color)&&(current!=f_color))

{

dc.SetPixel(x,y,f_color);

x--;

current=dc.GetPixel(x,y);

}

x=s_point.x;

}

}