矩形和区域

下面有三个绘图函数需要一个指向矩形结构的指针：

FillRect(hdc,&rect,hbursh);//填充

FrameRect(hdc,&rect,hbrush);//掏空

InvertRect(hdc,&rect);//内部取反

1. case WM_PAINT:  
2.             hdc=BeginPaint(hwnd,&ps);  
3.             //GetClientRect(hwnd,&rect);  
4.               
5.             //hrgn=CreateRectRgn(100,100,300,300);  
6.             //hbrush=CreateSolidBrush(RGB(255,0,0));  
7.             //FillRgn(hdc,hrgn,hbrush);  
8.             //InvertRgn(hdc,hrgn);//取反  
9.             //FrameRgn(hdc,hrgn,hbrush,0,0);  
10.   
11.               
12.             r1.left=100;  
13.             r1.top=100;  
14.             r1.right=200;  
15.             r1.bottom=200;  
16.             hbrush=CreateSolidBrush(RGB(255,0,0));//创建画刷  
17.             FillRect(hdc,&r1,hbrush);  
18.   
19.             r2.left=200;  
20.             r2.top=100;  
21.             r2.right=300;  
22.             r2.bottom=200;  
23.             FrameRect(hdc,&r2,hbrush);  
24.   
25.             r3.left=300;  
26.             r3.top=100;  
27.             r3.right=400;  
28.             r3.bottom=200;  
29.             InvertRect(hdc,&r3);  
30.   
31.             EndPaint(hwnd,&ps);  
32.             return 0;  

下面还有八个关于矩形的操作：

区域跟矩形一样，有以下四个绘图函数

1. FillRgn(hdc,hrgn,hbrush);  
2. FrameRgn(hdc,hbrush,xFrame,yFrame);  
3. InvertRgn(hdc,hrgn);  
4. PaintRgn(hdc,hrgn);  

1. DeleteObject(hrgn);  

1. SelectObject(hdc,hrgn)=SelectClipRgn(hdc,hrgn);  

使得矩形，区域有效和无效的函数

1. InvalidateRect       ValidateRect  
2. InvalidateRgn        ValidateRgn  

下面是简单的例子：

1. case WM_PAINT:  
2.             hdc=BeginPaint(hwnd,&ps);  
3.             //GetClientRect(hwnd,&rect);  
4.               
5.             //hrgn=CreateRectRgn(100,100,300,300);  
6.             //hbrush=CreateSolidBrush(RGB(255,0,0));  
7.             //FillRgn(hdc,hrgn,hbrush);  
8.             //InvertRgn(hdc,hrgn);//取反  
9.             //FrameRgn(hdc,hrgn,hbrush,0,0);  
10.   
11.               
12.             r1.left=100;  
13.             r1.top=100;  
14.             r1.right=200;  
15.             r1.bottom=200;  
16.             hbrush=CreateSolidBrush(RGB(255,0,0));//创建画刷  
17.             //FillRect(hdc,&r1,hbrush);  
18.   
19.             r2.left=150;  
20.             r2.top=100;  
21.             r2.right=250;  
22.             r2.bottom=200;  
23.             //FrameRect(hdc,&r2,hbrush);  
24.   
25.             IntersectRect(&r3,&r1,&r2);//r1,r2矩形取交集，存放在r3  
26.             FillRect(hdc,&r3,hbrush);  
27.             flag=(int)IsRectEmpty(&r3);//判断矩形是否为空  
28.             TextOut(hdc,300,300,szBuffer,wsprintf(szBuffer,TEXT("%d"),flag));  
29.   
30.             EndPaint(hwnd,&ps);  
31.             return 0;  

1. hrgn=CreateRectRgn(xleft,ytop,xright,ybottom);  
2. hrgn=CreateRectRgnIndirect(&rect);  
3. hrgn=CreateEllipticRgn(xleft,ytop,xright,ybottom);  
4. hrgn=CreatePolygonRgn(&point,icount,ipolyFillMode);