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)
http://msdn2.microsoft.com/en-us/library/ms533266.aspx
