第6章 键盘_6.5 插入符号（不是光标）

/*------------------------------------------------------------
TYPER.C -- Typeing Program
(c) Charles Petzold, 1998
------------------------------------------------------------*/
#include <windows.h>
#define  BUFFER(x,y) *(pBuffer+y*cxBuffer+x)
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
    PSTR szCmdLine, int iCmdShow)
{
    static TCHAR szAppName[] = TEXT("Typer");
    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("This program requires Windows NT!"),
            szAppName, MB_ICONERROR);
        return 0;
    }

    hwnd = CreateWindow(szAppName,                  // window class name
        TEXT("Typing Program"), // window caption
        WS_OVERLAPPEDWINDOW,        // window style
        CW_USEDEFAULT,              // initial x position
        CW_USEDEFAULT,              // initial y position
        CW_USEDEFAULT,              // initial x size
        CW_USEDEFAULT,              // initial y size
        NULL,                       // parent window handle
        NULL,                       // window menu handle
        hInstance,                  // program instance handle
        NULL);                     // creation parameters

    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)
{
    HDC         hdc;
    PAINTSTRUCT ps;
    TEXTMETRIC tm;
    static DWORD dwCharSet = DEFAULT_CHARSET;
    static int cxChar, cyChar, cxClient, cyClient, cxBuffer, cyBuffer;
    static int xCaret, yCaret;
    static TCHAR* pBuffer = NULL;

    switch (message)
    {
    case WM_INPUTLANGCHANGE:
        dwCharSet = wParam;
        //继续执行下去
    case WM_CREATE:
        hdc = GetDC(hwnd);
        SelectObject(hdc, CreateFont(0, 0, 0, 0, 0, 0, 0, 0,
            dwCharSet, 0, 0, 0, FIXED_PITCH, 0));
        GetTextMetrics(hdc, &tm);
        cxChar = tm.tmAveCharWidth;
        cyChar = tm.tmHeight;
        DeleteObject(SelectObject(hdc, GetStockObject(SYSTEM_FONT)));
        ReleaseDC(hwnd, hdc);
        //继续执行下去

    case WM_SIZE:
        if (message == WM_SIZE)
        {
            cxClient = LOWORD(lParam);
            cyClient = HIWORD(lParam);
        }

        //以字符尺寸为单位，计算窗口大小
        cxBuffer = max(1, cxClient / cxChar);
        cyBuffer = max(1, cyClient / cyChar);
        //分配字符数组内存大小
        if (pBuffer != NULL) free(pBuffer);
        pBuffer = (TCHAR*)malloc(cxBuffer*cyBuffer*sizeof(TCHAR*));

        for (int y = 0; y < cyBuffer; y++)
        for (int x = 0; x < cxBuffer; x++)
            BUFFER(x, y) = ‘ ‘;   //初始化pBuffer为一个‘ ’空字符
        //将光标置入左上角
        xCaret = 0;
        yCaret = 0;

        if (hwnd == GetFocus())
        {
            SetCaretPos(xCaret*cxChar, yCaret*cyChar);
        }

        //重绘
        InvalidateRect(hwnd, NULL, TRUE);
        return 0;
    case WM_SETFOCUS:
        CreateCaret(hwnd, NULL, 2, cyChar);
        SetCaretPos(xCaret*cxChar, yCaret*cyChar);
        ShowCaret(hwnd);
        return 0;
    case WM_KILLFOCUS:
        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_RIGHT:
            xCaret = min(xCaret + 1, cxBuffer - 1);
            break;
        case VK_LEFT:
            xCaret = max(0, xCaret - 1);
            break;
        case VK_UP:
            yCaret = max(0, yCaret - 1);
            break;
        case VK_DOWN:
            yCaret = min(yCaret + 1, cyBuffer - 1);
            break;
        case VK_DELETE: //注意VK_BACK键当字符消息去处理，这里只处理VK_DELETE
            //将该行从当前位置后面字符依次前移一格
            for (int x = xCaret; x < cxBuffer - 1; x++)
            {
                BUFFER(x, yCaret) = BUFFER(x + 1, yCaret);
            }
            BUFFER(cxBuffer - 1, yCaret) = ‘ ‘;//该行最后一个设为空字符。
            HideCaret(hwnd);
            hdc = GetDC(hwnd);
            SelectObject(hdc, CreateFont(0, 0, 0, 0, 0, 0, 0, 0,
                dwCharSet, 0, 0, 0, FIXED_PITCH, 0));
            TextOut(hdc, xCaret * cxChar, yCaret * cyChar, &BUFFER(xCaret, yCaret), cyBuffer - xCaret); //重新输出该行xCaret后面的文字
            DeleteObject(SelectObject(hdc, GetStockObject(SYSTEM_FONT)));
            ReleaseDC(hwnd, hdc);
            ShowCaret(hwnd);
            break;
        }
        SetCaretPos(xCaret*cxChar, yCaret*cyChar);
        return 0;
    case WM_CHAR:
        switch (wParam)
        {
        case ‘\b‘: //退格键
            if (xCaret>0)
            {
                xCaret--;
                SendMessage(hwnd, WM_KEYDOWN, VK_DELETE, 1); //1为repeat字段的值
            }
            break;
        case ‘\t‘: //Tab键，8个字符长度
            do
            {
                SendMessage(hwnd, WM_CHAR, ‘ ‘, 1);
            } while (xCaret % 8 != 0);
            break;
        case ‘\n‘: //换行符，改变y到下一行，x坐标没变。
            if (++yCaret == cyBuffer)
            {
                yCaret = 0;
            }
            break;
        case ‘\r‘: //回车键
            xCaret = 0;
            if (++yCaret == cyBuffer)
            {
                yCaret = 0;
            }
            break;
        case ‘\x1B‘:  //ESC键，清空屏幕 \xhh表示1到2位十六进制所代表的任意字符
            for (int x = 0; x < cxBuffer; x++)
            for (int y = 0; y < cyBuffer; y++)
                BUFFER(x, y) = ‘ ‘;
            xCaret = 0;
            yCaret = 0;

            InvalidateRect(hwnd, NULL, TRUE);
            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, 0));
            TextOut(hdc, xCaret * cxChar, yCaret * cyChar, &BUFFER(xCaret, yCaret), 1);
            DeleteObject(SelectObject(hdc, GetStockObject(SYSTEM_FONT)));
            ReleaseDC(hwnd, hdc);
            ShowCaret(hwnd);
            if (++xCaret == cxBuffer) //插入符号后移
            {
                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, 0));

        for (int 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:
        if (pBuffer != NULL) free(pBuffer);
        PostQuitMessage(0);
        return 0;
    }
    return DefWindowProc(hwnd, message, wParam, lParam);
}