pinvoke.net: Edit: gdi32.GetDeviceCaps

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Summary: The GetDeviceCaps API

!!!!C# Signature:
 [DllImport("gdi32.dll")]
 static extern int GetDeviceCaps(IntPtr hdc, int nIndex);
!!!!VB.NET Signature:
 <DllImport("gdi32.dll")> _
 Public Shared Function GetDeviceCaps(ByVal hDC As IntPtr, ByVal nIndex As Integer) As Integer
 End Function
!!!!User-Defined Types:

You can use the following enumeration for passing in as nIndex:

'''C#'''

public enum DeviceCap
        {
            /// <summary>
            /// Device driver version
            /// </summary>
            DRIVERVERSION = 0,
            /// <summary>
            /// Device classification
            /// </summary>
            TECHNOLOGY = 2,
            /// <summary>
            /// Horizontal size in millimeters
            /// </summary>
            HORZSIZE = 4,
            /// <summary>
            /// Vertical size in millimeters
            /// </summary>
            VERTSIZE = 6,
            /// <summary>
            /// Horizontal width in pixels
            /// </summary>
            HORZRES = 8,
            /// <summary>
            /// Vertical height in pixels
            /// </summary>
            VERTRES = 10,
            /// <summary>
            /// Number of bits per pixel
            /// </summary>
            BITSPIXEL = 12,
            /// <summary>
            /// Number of planes
            /// </summary>
            PLANES = 14,
            /// <summary>
            /// Number of brushes the device has
            /// </summary>
            NUMBRUSHES = 16,
            /// <summary>
            /// Number of pens the device has
            /// </summary>
            NUMPENS = 18,
            /// <summary>
            /// Number of markers the device has
            /// </summary>
            NUMMARKERS = 20,
            /// <summary>
            /// Number of fonts the device has
            /// </summary>
            NUMFONTS = 22,
            /// <summary>
            /// Number of colors the device supports
            /// </summary>
            NUMCOLORS = 24,
            /// <summary>
            /// Size required for device descriptor
            /// </summary>
            PDEVICESIZE = 26,
            /// <summary>
            /// Curve capabilities
            /// </summary>
            CURVECAPS = 28,
            /// <summary>
            /// Line capabilities
            /// </summary>
            LINECAPS = 30,
            /// <summary>
            /// Polygonal capabilities
            /// </summary>
            POLYGONALCAPS = 32,
            /// <summary>
            /// Text capabilities
            /// </summary>
            TEXTCAPS = 34,
            /// <summary>
            /// Clipping capabilities
            /// </summary>
            CLIPCAPS = 36,
            /// <summary>
            /// Bitblt capabilities
            /// </summary>
            RASTERCAPS = 38,
            /// <summary>
            /// Length of the X leg
            /// </summary>
            ASPECTX = 40,
            /// <summary>
            /// Length of the Y leg
            /// </summary>
            ASPECTY = 42,
            /// <summary>
            /// Length of the hypotenuse
            /// </summary>
            ASPECTXY = 44,
            /// <summary>
            /// Shading and Blending caps
            /// </summary>
            SHADEBLENDCAPS = 45,

/// <summary>
            /// Logical pixels inch in X
            /// </summary>
            LOGPIXELSX = 88,
            /// <summary>
            /// Logical pixels inch in Y
            /// </summary>
            LOGPIXELSY = 90,

/// <summary>
            /// Number of entries in physical palette
            /// </summary>
            SIZEPALETTE = 104,
            /// <summary>
            /// Number of reserved entries in palette
            /// </summary>
            NUMRESERVED = 106,
            /// <summary>
            /// Actual color resolution
            /// </summary>
            COLORRES = 108,

// Printing related DeviceCaps. These replace the appropriate Escapes
            /// <summary>
            /// Physical Width in device units
            /// </summary>
            PHYSICALWIDTH = 110,
            /// <summary>
            /// Physical Height in device units
            /// </summary>
            PHYSICALHEIGHT = 111,
            /// <summary>
            /// Physical Printable Area x margin
            /// </summary>
            PHYSICALOFFSETX = 112,
            /// <summary>
            /// Physical Printable Area y margin
            /// </summary>
            PHYSICALOFFSETY = 113,
            /// <summary>
            /// Scaling factor x
            /// </summary>
            SCALINGFACTORX = 114,
            /// <summary>
            /// Scaling factor y
            /// </summary>
            SCALINGFACTORY = 115,

/// <summary>
            /// Current vertical refresh rate of the display device (for displays only) in Hz
            /// </summary>
            VREFRESH = 116,
            /// <summary>
            /// Vertical height of entire desktop in pixels
            /// </summary>
            DESKTOPVERTRES = 117,
            /// <summary>
            /// Horizontal width of entire desktop in pixels
            /// </summary>
            DESKTOPHORZRES = 118,
            /// <summary>
            /// Preferred blt alignment
            /// </summary>
            BLTALIGNMENT = 119
        }

'''VB'''
    Public Enum DeviceCap As Integer

''' <summary>
        ''' Device driver version
        ''' </summary>
        DRIVERVERSION = 0
        ''' <summary>
        ''' Device classification
        ''' </summary>
        TECHNOLOGY = 2
        ''' <summary>
        ''' Horizontal size in millimeters
        ''' </summary>
        HORZSIZE = 4
        ''' <summary>
        ''' Vertical size in millimeters
        ''' </summary>
        VERTSIZE = 6
        ''' <summary>
        ''' Horizontal width in pixels
        ''' </summary>
        HORZRES = 8
        ''' <summary>
        ''' Vertical height in pixels
        ''' </summary>
        VERTRES = 10
        ''' <summary>
        ''' Number of bits per pixel
        ''' </summary>
        BITSPIXEL = 12
        ''' <summary>
        ''' Number of planes
        ''' </summary>
        PLANES = 14
        ''' <summary>
        ''' Number of brushes the device has
        ''' </summary>
        NUMBRUSHES = 16
        ''' <summary>
        ''' Number of pens the device has
        ''' </summary>
        NUMPENS = 18
        ''' <summary>
        ''' Number of markers the device has
        ''' </summary>
        NUMMARKERS = 20
        ''' <summary>
        ''' Number of fonts the device has
        ''' </summary>
        NUMFONTS = 22
        ''' <summary>
        ''' Number of colors the device supports
        ''' </summary>
        NUMCOLORS = 24
        ''' <summary>
        ''' Size required for device descriptor
        ''' </summary>
        PDEVICESIZE = 26
        ''' <summary>
        ''' Curve capabilities
        ''' </summary>
        CURVECAPS = 28
        ''' <summary>
        ''' Line capabilities
        ''' </summary>
        LINECAPS = 30
        ''' <summary>
        ''' Polygonal capabilities
        ''' </summary>
        POLYGONALCAPS = 32
        ''' <summary>
        ''' Text capabilities
        ''' </summary>
        TEXTCAPS = 34
        ''' <summary>
        ''' Clipping capabilities
        ''' </summary>
        CLIPCAPS = 36
        ''' <summary>
        ''' Bitblt capabilities
        ''' </summary>
        RASTERCAPS = 38
        ''' <summary>
        ''' Length of the X leg
        ''' </summary>
        ASPECTX = 40
        ''' <summary>
        ''' Length of the Y leg
        ''' </summary>
        ASPECTY = 42
        ''' <summary>
        ''' Length of the hypotenuse
        ''' </summary>
        ASPECTXY = 44
        ''' <summary>
        ''' Shading and Blending caps
        ''' </summary>
        SHADEBLENDCAPS = 45

''' <summary>
        ''' Logical pixels inch in X
        ''' </summary>
        LOGPIXELSX = 88
        ''' <summary>
        ''' Logical pixels inch in Y
        ''' </summary>
        LOGPIXELSY = 90

''' <summary>
        ''' Number of entries in physical palette
        ''' </summary>
        SIZEPALETTE = 104
        ''' <summary>
        ''' Number of reserved entries in palette
        ''' </summary>
        NUMRESERVED = 106
        ''' <summary>
        ''' Actual color resolution
        ''' </summary>
        COLORRES = 108

' Printing related DeviceCaps. These replace the appropriate Escapes

''' <summary>
        ''' Physical Width in device units
        ''' </summary>
        PHYSICALWIDTH = 110
        ''' <summary>
        ''' Physical Height in device units
        ''' </summary>
        PHYSICALHEIGHT = 111
        ''' <summary>
        ''' Physical Printable Area x margin
        ''' </summary>
        PHYSICALOFFSETX = 112
        ''' <summary>
        ''' Physical Printable Area y margin
        ''' </summary>
        PHYSICALOFFSETY = 113
        ''' <summary>
        ''' Scaling factor x
        ''' </summary>
        SCALINGFACTORX = 114
        ''' <summary>
        ''' Scaling factor y
        ''' </summary>
        SCALINGFACTORY = 115

''' <summary>
        ''' Current vertical refresh rate of the display device (for displays only) in Hz
        ''' </summary>
        VREFRESH = 116
        ''' <summary>
        ''' Vertical height of entire desktop in pixels
        ''' </summary>
        DESKTOPVERTRES = 117
        ''' <summary>
        ''' Horizontal width of entire desktop in pixels
        ''' </summary>
        DESKTOPHORZRES = 118
        ''' <summary>
        ''' Preferred blt alignment
        ''' </summary>
        BLTALIGNMENT = 119

End Enum

!!!!Notes:
None.

!!!!Tips & Tricks:
Please add some!

!!!!Sample Code:
'''C#'''

static void Main(string[] args)
        {
            using (System.Drawing.Graphics g = System.Drawing.Graphics.FromHwnd(IntPtr.Zero))
            {
                Console.WriteLine("Graphics.DpiX: " + g.DpiX);
                Console.WriteLine("Graphics.DpiY: " + g.DpiY);
                Console.WriteLine();

IntPtr hdc = g.GetHdc();

foreach (DeviceCap cap in Enum.GetValues(typeof(DeviceCap)))
                {
                    int result = GetDeviceCaps(hdc, cap);
                    Console.WriteLine(string.Format("{0}: {1}", cap, result));
                }

g.ReleaseHdc();
            }

Console.WriteLine();
            Console.Write("Press any key to exit...");
            Console.ReadKey();
	}

'''VB'''
	Private Shared Sub Main(args As String())
		Using g As System.Drawing.Graphics = System.Drawing.Graphics.FromHwnd(IntPtr.Zero)
			Console.WriteLine("Graphics.DpiX: " & g.DpiX)
			Console.WriteLine("Graphics.DpiY: " & g.DpiY)
			Console.WriteLine()

Dim hdc As IntPtr = g.GetHdc()

For Each cap As DeviceCap In [Enum].GetValues(GetType(DeviceCap))
				Dim result As Integer = GetDeviceCaps(hdc, cap)
				Console.WriteLine(String.Format("{0}: {1}", cap, result))
			Next

g.ReleaseHdc()
		End Using

Console.WriteLine()
		Console.Write("Press any key to exit...")
		Console.ReadKey()
	End Sub

!!!!Alternative Managed API:
System.Windows.Forms.Screen.PrimaryScreen might be of help in some cases. (Matt M Jacobsen)

If you are using Graphics as a DeviceContext you can use the DpiX and DpiY attributes. (Julian Taupe)

Documentation: GetDeviceCaps@msdn on MSDN
http://msdn2.microsoft.com/en-us/library/ms533266.aspx