第五章 BEZIER

#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("BEZIER");
HWND hWnd;
tagMSG msg;
WNDCLASS wndclass;

wndclass.cbClsExtra=0;
wndclass.cbWndExtra=0;
wndclass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);
wndclass.hCursor=LoadCursor(NULL,IDC_ARROW);
wndclass.hIcon=LoadIcon(NULL,IDI_APPLICATION);
wndclass.hInstance=hInstance;
wndclass.lpfnWndProc=WndProc;
wndclass.lpszClassName=szAppName;
wndclass.lpszMenuName=NULL;
wndclass.style=CS_HREDRAW|CS_VREDRAW;

if(!RegisterClass(&wndclass))
{
MessageBox(NULL,TEXT("注册类错误！！"),szAppName,MB_ICONERROR);
return 0;
}

hWnd=CreateWindow(szAppName,TEXT("EXAMPLE BEZIER"),WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,
CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,NULL,NULL,hInstance,NULL);
ShowWindow(hWnd,nShowCmd);
UpdateWindow(hWnd);

while(GetMessage(&msg,hWnd,0,0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}
void DrawBezier(HDC hdc,POINT apt[])
{
PolyBezier(hdc,apt,4);

MoveToEx(hdc,apt[0].x,apt[0].y,NULL);
LineTo(hdc,apt[1].x,apt[1].y);

MoveToEx(hdc,apt[2].x,apt[2].y,NULL);
LineTo(hdc,apt[3].x,apt[3].y);
}
LRESULT CALLBACK WndProc(HWND hWnd,UINT message,WPARAM wParam,LPARAM lParam)
{
static POINT apt[4];
HDC hdc;
static int cxClient,cyClient;
PAINTSTRUCT ps;
switch (message)
{
case WM_SIZE:
cxClient=LOWORD(lParam);
cyClient=HIWORD(lParam);

apt[0].x=cxClient/4;           //当窗口改变，设置贝塞尔曲线的初始值
apt[0].y=cyClient/2;

apt[1].x=cxClient/2;
apt[1].y=cyClient/4;

apt[2].x=cxClient/2;
apt[2].y=3*cyClient/4;

apt[3].x=3*cxClient/4;
apt[3].y=cyClient/2;
return 0;
case WM_LBUTTONDOWN:
case WM_RBUTTONDOWN:
case WM_MOUSEMOVE:
if(wParam&MK_LBUTTON||wParam&MK_RBUTTON)
{
hdc=GetDC(hWnd);
SelectObject(hdc,GetStockObject(WHITE_PEN));   //选择画笔颜色,将原来的图擦除
DrawBezier(hdc,apt);
if(wParam&MK_LBUTTON)                     //鼠标移动同时按下了鼠标左键或者右键
{
apt[1].x=LOWORD(lParam);              //记录鼠标的位置，左键表示改变第一个控点
apt[1].y=HIWORD(lParam);
}
if(wParam&MK_RBUTTON)
{
apt[2].x=LOWORD(lParam);              //右键表示改变第二个控点
apt[2].y=HIWORD(lParam);
}
SelectObject(hdc,GetStockObject(BLACK_PEN));   //将画笔颜色还原
DrawBezier(hdc,apt);
ReleaseDC(hWnd,hdc);
}
return 0;
case WM_PAINT:
InvalidateRect(hWnd,NULL,true);
hdc=BeginPaint(hWnd,&ps);
DrawBezier(hdc,apt);
return 0;
case WM_DESTROY:
PostQuitMessage(0);
return 0;
}
return DefWindowProc(hWnd,message,wParam,lParam);
}