第七章 鼠标（CONNECT）

/*
CONNECT.C -- Connect-the-Dots Mouse Demo Program
            (c) Charles Petzold,1998
*/

#include <Windows.h>

#define MAXPOINTS 1000

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

int WINAPI WinMain( __in HINSTANCE hInstance
                    , __in_opt HINSTANCE hPrevInstance
                    , __in LPSTR lpCmdLine
                    , __in int nShowCmd )
{
    static TCHAR szAppName[] = TEXT("Connect");
    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("Connect-the-Points Mouse Demo")
        , 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 pt[MAXPOINTS];
    static int iCount;
    HDC hdc;
    int i, j;
    PAINTSTRUCT ps;

    switch (message)
    {
    case WM_LBUTTONDOWN:
        iCount = 0;
        InvalidateRect(hwnd, NULL, TRUE);
        return 0;

    case WM_MOUSEMOVE:
        if (wParam & MK_LBUTTON && iCount < 1000)
        {
            pt[iCount  ].x = LOWORD(lParam);
            pt[iCount++].y = HIWORD(lParam);
            
            hdc = GetDC(hwnd);
            SetPixel(hdc, LOWORD(lParam), HIWORD(lParam), 0);
            ReleaseDC(hwnd, hdc);
        }
        return 0;

    case WM_LBUTTONUP:
        InvalidateRect(hwnd, NULL, FALSE);
        return 0;

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

        SetCursor(LoadCursor(NULL, IDC_WAIT));
        ShowCursor(TRUE);

        for (i = 0; i < iCount - 1; ++i)
            for (j = i + 1; j < iCount; ++j)
            {
                MoveToEx(hdc, pt[i].x, pt[i].y, NULL);
                LineTo(hdc, pt[j].x, pt[j].y);
            }

        ShowCursor(FALSE);
        SetCursor(LoadCursor(NULL, IDC_ARROW));

        EndPaint(hwnd, &ps);
        return 0;

    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }

    return DefWindowProc(hwnd, message, wParam, lParam);
}