C# API GetDeviceCaps

 [DllImport("gdi32.dll")]
    public static extern int GetDeviceCaps(
    IntPtr hdc, // handle to DC
    int nIndex // index of capability
    );

nIndex:

const int DRIVERVERSION = 0;

const int TECHNOLOGY = 2;

const int HORZSIZE = 4;

const int VERTSIZE = 6;

const int HORZRES = 8;

const int VERTRES = 10;

const int BITSPIXEL = 12;

const int PLANES = 14;

const int NUMBRUSHES = 16;

const int NUMPENS = 18;

const int NUMMARKERS = 20;

const int NUMFONTS = 22;

const int NUMCOLORS = 24;

const int PDEVICESIZE = 26;

const int CURVECAPS = 28;

const int LINECAPS = 30;

const int POLYGONALCAPS = 32;

const int TEXTCAPS = 34;

const int CLIPCAPS = 36;

const int RASTERCAPS = 38;

const int ASPECTX = 40;

const int ASPECTY = 42;

const int ASPECTXY = 44;

const int SHADEBLENDCAPS = 45;

const int LOGPIXELSX = 88;

const int LOGPIXELSY = 90;

const int SIZEPALETTE = 104;

const int NUMRESERVED = 106;

const int COLORRES = 108;

const int PHYSICALWIDTH = 110;

const int PHYSICALHEIGHT = 111;

const int PHYSICALOFFSETX = 112;

const int PHYSICALOFFSETY = 113;

const int SCALINGFACTORX = 114;

const int SCALINGFACTORY = 115;

const int VREFRESH = 116;

const int DESKTOPVERTRES = 117;

const int DESKTOPHORZRES = 118;

const int BLTALIGNMENT = 119;

}

 

GetDeviceCaps（HORZSIZE）

HORZSIZE 以毫米为单位的显示宽度

VERTSIZE 以毫米为单位的显示高度

HORZRES 以像素为单位的显示宽度 0~65535

VERTRES 以像素为单位的显示高度 0~65535

LOGPIXELSX 像素/逻辑英寸（水平）

LOGPIXELSY 像素/逻辑英寸（垂直）