学步园

下表列出了 Windows 用于绘制带有边框的填充区域的 7 个函数：

Windows 使用当前选入设备环境的画刷来填充图形。在默认情况下，使用的是备用对象 WHITE_BRUSH ,这就意味着使用白色来绘制图形内部。 Windows 定义了 6 种备用画刷：

WHITE_BRUSH,  LTGRAY_BRUSH,  GRAY_BRUSH,  DKGRAY_BRUSH,  BLACK_BRUSH  和 NULL_BRUSH （又被称为 HOLLOW_BRUSH )。和选择备用画笔一样，可以将任何一种备用画刷选入设备环境。Windows 定于画刷的句柄为 HBRUSH 类型，所以要先定义一个画刷句柄的变量：

  HBRUSH  hBrush ;

获取 GRAY_BRUSH 句柄可以通过调用如下的 GetStockObject 函数实现：

  hBrush = GetStockObject ( GRAY_BRUSH ) ;

然后通过调用 SelectObject 函数将它选进设备环境：

  SelectObject ( hdc, bBrush ) ;

示例代码如下：

#include<windows.h>

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd )
{
static TCHAR szAppName[] = TEXT("AltWin");
HWND hwnd;
MSG msg;
WNDCLASS wndclass;
wndclass.style = CS_HREDRAW | CS_VREDRAW ;
wndclass.lpfnWndProc = WndProc ;
wndclass.cbClsExtra = 0 ;
wndclass.cbWndExtra = 0 ;
wndclass.hInstance = hInstance ;
wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wndclass.hCursor = LoadCursor(NULL,IDC_ARROW);
wndclass.hbrBackground = (HBRUSH) GetStockObject(WHITE_BRUSH);
wndclass.lpszMenuName = NULL ;
wndclass.lpszClassName = szAppName ;

if(!RegisterClass(&wndclass))
{
MessageBox (NULL,TEXT ("Program requires Windows NT!"),szAppName,MB_ICONERROR);
return 0;
}

hwnd = CreateWindow(szAppName,TEXT("Alternate and Winding Fill Modes"),WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,NULL,NULL,hInstance,NULL);
ShowWindow(hwnd,nShowCmd);
UpdateWindow(hwnd);

while (GetMessage(&msg, NULL,0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}

return msg.wParam ;

}

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
static POINT aptFigure [10] = {10, 70, 50, 70, 50, 10, 90, 10, 90, 50, 30, 50, 30, 90, 70, 90, 70, 30, 10, 30};
static int cxClient, cyClient ;
HDC hdc;
int i;
PAINTSTRUCT ps;
POINT apt[10];

switch (message)
{
case WM_SIZE:
cxClient = LOWORD (lParam);
cyClient = HIWORD (lParam);
        return 0;

case WM_PAINT:
hdc = BeginPaint(hwnd,&ps);

SelectObject(hdc,GetStockObject(GRAY_BRUSH));

for(i = 0; i < 10; i++)
{
apt[i].x = cxClient * aptFigure[i].x /200 ;
apt[i].y = cyClient * aptFigure[i].y /100 ;
}

SetPolyFillMode(hdc,ALTERNATE);
Polygon(hdc, apt, 10);

for (i = 0; i < 10; i++)
{
apt[i].x +=cxClient /2 ;
}

SetPolyFillMode(hdc, WINDING);
Polygon(hdc, apt, 10);

EndPaint(hwnd,&ps);
return 0;

case WM_DESTROY:
PostQuitMessage (0);
return 0;
}
return DefWindowProc(hwnd,message,wParam,lParam);
}

运行结果：

以上两个图形分别是用ALTETNATE(交替) 和 WINDING(螺旋) 填充模式绘制的图形。