简单的利用windows api来实现的贝赛尔曲线。两个端点是固定的，，垂直方向的位置为显示区域高度的一半，水平方向则分别位于显示宽度的1/4和3/4处。
两个控点可以改变，按住鼠标左键并拖动鼠标可以改变第一个控点，按住右键并拖动鼠标可以改变第二个控点。
如图：
代码如下：
#include <windows.h> LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM); int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow) { static TCHAR szAppName[] = TEXT("贝塞尔曲线"); 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("这个程序需要运行在Windows NT下！"), szAppName, MB_ICONERROR); return 0; } hwnd = CreateWindow(szAppName, TEXT("贝塞尔曲线！"), WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, hInstance, NULL); ShowWindow(hwnd, iCmdShow); UpdateWindow(hwnd); while (GetMessage(&msg, NULL, 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; int cxClient, cyClient; PAINTSTRUCT ps; switch (message) { case WM_SIZE: cxClient = LOWORD(lParam); cyClient = HIWORD(lParam); apt[0].x = cxClient / 4; 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; case WM_LBUTTONDOWN: case WM_RBUTTONDOWN: case WM_MOUSEMOVE: if (wParam & MK_LBUTTON || wParam && MK_RBUTTON) { hdc = GetDC(hwnd); SelectObject(hdc, GetStockObject(WHITE_PEN)); DrawBezier(hdc, apt); if (wParam & MK_LBUTTON) { apt[1].x = LOWORD(lParam); apt[1].y = HIWORD(lParam); } if (wParam & MK_RBUTTON) { apt[2].x = LOWORD(lParam); apt[2].y = HIWORD(lParam); } SelectObject(hdc, GetStockObject(BLACK_PEN)); DrawBezier(hdc, apt); ReleaseDC(hwnd, hdc); } return 0; case WM_PAINT: InvalidateRect(hwnd, NULL, TRUE); hdc = BeginPaint(hwnd, &ps); DrawBezier(hdc, apt); EndPaint(hwnd, &ps); return 0; case WM_DESTROY: PostQuitMessage(0); return 0; } return DefWindowProc(hwnd, message, wParam, lParam); }
win32下的贝塞尔曲线