文本编辑器雏形

#include <windows.h>

#define BUFFER(x,y) *(pBuffer + y*cxBuffer + x) 

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

int min(int a, int b)
{
    return a>b?b:a;
}

int max(int a, int b)
{
    return a>b?a:b;
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow) 
{
    static TCHAR szAppName[] = TEXT("Typer");
    WNDCLASS     wndclass; 
    HWND         hwnd; 
    MSG          msg; 

    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("This program requires Windows NT !"), szAppName, MB_ICONERROR);
        return 0;
    }

    hwnd = CreateWindow(szAppName, TEXT("Typing Program"),
                        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;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) 
{
    static DWORD    wCharSet = DEFAULT_CHARSET;
    static int      cxChar, cyChar, cxClient, cyClient,
                    cxBuffer, cyBuffer, xCaret, yCaret;
    static TCHAR*   pBuffer = NULL;
    HDC             hdc;
    int             x, y, i;
    PAINTSTRUCT     ps;
    TEXTMETRIC      tm;
    
    switch(message) 
    {
    case WM_INPUTLANGCHANGE:
        dwCharSet = wParam;
        //fall through
    case WM_CREATE:
        hdc = GetDC(hwnd);
        SelectObject(hdc, CreateFont(0, 0, 0, 0, 0, 0, 0, 0,
                                    dwCharSet, 0, 0, 0, FIXED_PITCH, NULL));
        GetTextMetrics(hdc, &tm);
        cxChar = tm.tmAveCharWidth;
        cyChar = tm.tmHeight;
        
        DeleteObject(SelectObject(hdc,GetStockObject(SYSTEM_FONT)));
        ReleaseDC(hwnd, hdc);
        //fall through
    case WM_SIZE:
        if(message == WM_SIZE)
        {
            cxClient = LOWORD(lParam);
            cyClient = HIWORD(lParam);
        }
        //calculate window size in characters
        cxBuffer = max(1, cxClient/cxChar);
        cyBuffer = max(1, cyClient/cyChar);
        //allocate memory for buffer and clear it
        if(pBuffer != NULL)
            free(pBuffer);
            
        pBuffer = (TCHAR*)malloc(cxBuffer*cyBuffer*sizeof(TCHAR));
        
        for(y=0; y<cyBuffer; y++)
            for(x=0; x<cxBuffer; x++)
                BUFFER(x, y) = ‘ ‘;
        //set caret to upper left corner
        xCaret = 0;
        yCaret = 0;
        
        if(hwnd == GetFocus())
            SetCaretPos(xCaret*cxChar, yCaret*cyChar);
            
        InvalidateRect(hwnd, NULL, TRUE);
        return 0;
    case WM_SETFOCUS:
        //create and show the caret
        CreateCaret(hwnd, NULL, cxChar, cyChar);
        SetCaretPos(xCaret*cxChar, yCaret*cyChar);
        ShowCaret(hwnd);
        return 0;
    case WM_KILLFOCUS:
        //hide and destroy the caret
        HideCaret(hwnd);
        DestroyCaret();
        return 0;
        
    case WM_KEYDOWN:
        switch(wParam)
        {
        case VK_HOME:
            xCaret = 0;
            break;
        case VK_END:
            xCaret = cxBuffer - 1;
            break;
        case VK_PRIOR:
            yCaret = 0;
            break;
        case VK_NEXT:
            yCaret = cyBuffer - 1;
            break;
        case VK_LEFT:
            xCaret = max(xCaret-1, 0);
            break;
        case VK_RIGHT:
            xCaret = min(xCaret+1, cxBuffer-1);
            break;
        case VK_DOWN:
            yCaret = min(yCaret+1, cyBuffer-1);
            break;
        case VK_UP:
            yCaret = max(yCaret-1, 0);
            break;
        case VK_DELETE:
            for(x=xCaret; x<cxBuffer-1; x++)
                BUFFER(x, yCaret) = BUFFER(x+1, yCaret);
            BUFFER(cxBuffer-1, yCaret) = ‘ ‘;
            HideCaret(hwnd);
            hdc = GetDC(hwnd);
            SelectObject(hdc, CreateFont(0, 0, 0, 0, 0, 0, 0, 0,
                                        dwCharSet, 0, 0, 0, FIXED_PITCH, NULL));
            TextOut(hdc, xCaret*cxChar, yCaret*cyChar,
                    & BUFFER(xCaret, yCaret),
                    cxBuffer-xCaret);
            DeleteObject(SelectObject(hdc, GetStockObject(SYSTEM_FONT)));
            ReleaseDC(hwnd, hdc);
            ShowCaret(hwnd);
            break;
        }
        SetCaretPos(xCaret*cxChar, yCaret*cyChar);
        return 0;
    
    case WM_CHAR:
        for(i=0; i<(int)LOWORD(lParam); i++)
        {
            switch(wParam)
            {
            case ‘\b‘:
                if(xCaret>0)
                {
                    xCaret--;
                    SendMessage(hwnd, WM_KEYDOWN, VK_DELETE, 1);
                }
                break;
            case ‘\t‘:
                do
                {
                    SendMessage(hwnd, WM_CHAR, ‘ ‘, 1);
                }while(xCaret%8!=0);
                break;
            case ‘\n‘:
                if(++yCaret == cyBuffer)
                    yCaret = 0;
                break;
            case ‘\r‘:
                xCaret = 0;
                if(++yCaret == cyBuffer)
                    yCaret= 0;
                break;
            case ‘\X1B‘:
                for(y=0; y<cyBuffer; y++)
                    for(x=0; x<cxBuffer; x++)
                        BUFFER(x,y) = ‘ ‘; 
                xCaret = 0;
                yCaret = 0;
                InvalidateRect(hwnd, NULL, FALSE);
                break;
            default:
                BUFFER(xCaret, yCaret) = (TCHAR) wParam;
                HideCaret(hwnd);
                hdc = GetDC(hwnd);
                SelectObject(hdc, CreateFont(0, 0, 0, 0, 0, 0, 0, 0,
                                dwCharSet, 0, 0, 0, FIXED_PITCH, NULL));
                TextOut(hdc, xCaret*cxChar, yCaret*cyChar,
                        & BUFFER(xCaret, yCaret), 1);
                DeleteObject(SelectObject(hdc, GetStockObject(SYSTEM_FONT)));
                ReleaseDC(hwnd, hdc);
                ShowCaret(hwnd);
                
                if(++xCaret == cxBuffer)
                {
                    xCaret = 0;
                    if(++yCaret == cyBuffer)
                        yCaret = 0;
                }
                break;
            }
        }
        
        SetCaretPos(xCaret*cxChar, yCaret*cyChar);
        return 0;
        
    case WM_PAINT:
        hdc = BeginPaint(hwnd, &ps);
        SelectObject(hdc, CreateFont(0, 0, 0, 0, 0, 0, 0, 0,
                                    dwCharSet, 0, 0, 0, FIXED_PITCH, NULL));
        
        for(y=0; y<cyBuffer; y++)
            TextOut(hdc, 0, y*cyChar, & BUFFER(0, y), cxBuffer);
            
        DeleteObject(SelectObject(hdc,GetStockObject(SYSTEM_FONT)));
        EndPaint(hwnd, &ps);
        return 0;
        
    case WM_DESTROY: 
        PostQuitMessage(0);
        return 0;            
    }
    return DefWindowProc(hwnd, message, wParam, lParam);
}