使用 GetDeviceCaps 函数获取视频显示器设备环境信息

#include <windows.h>

#define NUMLINES ((int)(sizeof devcaps / sizeof devcaps[0]))

struct 
{
    int        iIndex;
    TCHAR*     szLabel;
    TCHAR*     szDesc;
}
devcaps[] = 
{
    HORZSIZE,        TEXT("HORZSIZE"),    TEXT("Width in millimeters:"),
    VERTSIZE,        TEXT("VERTSIZE"),    TEXT("Height in millimters:"),
    HORZRES,         TEXT("HORZRES"),     TEXT("Width in pixels:"),
    VERTRES,         TEXT("VERTRES"),     TEXT("Height in raster lines:"),
    BITSPIXEL,       TEXT("BITSPIXEL"),   TEXT("Color bits per pixel:"),
    PLANES,          TEXT("PLANES"),      TEXT("Number of color planes"),
    NUMBRUSHES,      TEXT("NUMBRUSHES"),  TEXT("Number of device brushes"),
    NUMPENS,         TEXT("NUMPENS"),     TEXT("Number of device pens:"),
    NUMMARKERS,      TEXT("NUMMARKERS"),  TEXT("Number of device markers:"),
    NUMFONTS,        TEXT("NUMFONTS"),    TEXT("Number of device fonts:"),
    NUMCOLORS,       TEXT("NUMCOLORS"),   TEXT("Number of device colors:"),
    PDEVICESIZE,     TEXT("PDEVICESIZE"), TEXT("Size of device structure:"),
    ASPECTX,         TEXT("ASPECTX"),     TEXT("Relative width of pixel:"),
    ASPECTY,         TEXT("ASPECTY"),     TEXT("Relative height of pixel:"),
    ASPECTXY,        TEXT("ASPECTXY"),    TEXT("Relative diagonal of pixel:"),
    LOGPIXELSX,      TEXT("LOGPIXELSX"),  TEXT("Horizontal dots per inch:"),
    LOGPIXELSY,      TEXT("LOGPIXELSY"),  TEXT("Vertical dots per inch:"),
    SIZEPALETTE,     TEXT("SIZEPALETTE"), TEXT("Number of palette entries:"),
    NUMRESERVED,     TEXT("NUMRESERVED"), TEXT("Reserved palette entries:"),
    COLORRES,        TEXT("COLORRES"),    TEXT("Actual color resolution:")
};

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

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow) 
{
    static TCHAR   szAppName[] = TEXT("DevCaps1"); 
    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("Device Capabilities"),
                        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 int         cxChar, cxCaps, cyChar;
    TCHAR              szBuffer[10];
    HDC                hdc;
    int                i;
    PAINTSTRUCT        ps;
    TEXTMETRIC         tm;
    
    switch(message) 
    {    
    case WM_CREATE:
        hdc = GetDC(hwnd);
        
        GetTextMetrics(hdc, &tm);
        cxChar = tm.tmAveCharWidth;
        cxCaps = (tm.tmPitchAndFamily & 1 ? 3 : 2) * cxChar / 2;
        cyChar = tm.tmHeight + tm.tmExternalLeading;
        
        ReleaseDC(hwnd, hdc);
        return 0;
        
    case WM_PAINT:
        hdc = BeginPaint(hwnd, &ps);
        
        for(i=0;i<NUMLINES;i++)
        {
            TextOut(hdc, 0, cyChar*i,
                    devcaps[i].szLabel,
                    lstrlen(devcaps[i].szLabel));
            
            TextOut(hdc, 14*cxCaps, cyChar*i,
                    devcaps[i].szDesc,
                    lstrlen(devcaps[i].szDesc));
            
            SetTextAlign(hdc, TA_RIGHT | TA_TOP);
            
            TextOut(hdc, 14*cxCaps+35*cxChar, cyChar*i,
                    szBuffer,
                    wsprintf(szBuffer, TEXT("%5d"), GetDeviceCaps(hdc, devcaps[i].iIndex)));
            
            SetTextAlign(hdc, TA_LEFT | TA_TOP);
        } 
        
        EndPaint(hwnd, &ps);
        return 0;
        
    case WM_DESTROY: 
        PostQuitMessage(0);
        return 0;            
    }
    return DefWindowProc(hwnd, message, wParam, lParam);
}