GetDeviceCaps

The GetDeviceCaps function retrieves device-specific information about a specified device.

int GetDeviceCaps(

HDC hdc, // device-context handle
int nIndex // index of capability to query
);  

Parameters

hdc

Identifies the device context.

nIndex

Specifies the item to return. This parameter can be one of the following values:

Index Meaning
DRIVERVERSION The device driver version.
TECHNOLOGY Device technology. It can be any one of the following values:

Value Meaning
DT_PLOTTER Vector plotter
DT_RASDISPLAY Raster display
DT_RASPRINTER Raster printer
DT_RASCAMERA Raster camera
DT_CHARSTREAM Character stream
DT_METAFILE Metafile
DT_DISPFILE Display file

If the hdc parameter identifies the device context of an enhanced metafile, the device technology is that of the referenced device as given to the CreateEnhMetaFile function. To determine whether it is an enhanced metafile device context, use the GetObjectType function.
HORZSIZE Width, in millimeters, of the physical screen.
VERTSIZE Height, in millimeters, of the physical screen.
HORZRES Width, in pixels, of the screen.
VERTRES Height, in raster lines, of the screen.
LOGPIXELSX Number of pixels per logical inch along the screen width.
LOGPIXELSY Number of pixels per logical inch along the screen height.
BITSPIXEL Number of adjacent color bits for each pixel.
PLANES Number of color planes.
NUMBRUSHES Number of device-specific brushes.
NUMPENS Number of device-specific pens.
NUMFONTS Number of device-specific fonts.
NUMCOLORS Number of entries in the device's color table, if the device has a color depth of no more than 8 bits per pixel. For devices with greater color depths, -1 is returned.
ASPECTX Relative width of a device pixel used for line drawing.
ASPECTY Relative height of a device pixel used for line drawing.
ASPECTXY Diagonal width of the device pixel used for line drawing.
PDEVICESIZE Reserved.
CLIPCAPS Flag that indicates the clipping capabilities of the device. If the device can clip to a rectangle, it is 1. Otherwise, it is 0.
SIZEPALETTE Number of entries in the system palette. This index is valid only if the device driver sets the RC_PALETTE bit in the RASTERCAPS index and is available only if the driver is compatible with Windows version 3.0 or later.
NUMRESERVED Number of reserved entries in the system palette. This index is valid only if the device driver sets the RC_PALETTE bit in the RASTERCAPS index and is available only if the driver is compatible with Windows version 3.0 or later.
COLORRES Actual color resolution of the device, in bits per pixel. This index is valid only if the device driver sets the RC_PALETTE bit in the RASTERCAPS index and is available only if the driver is compatible with Windows version 3.0 or later.
PHYSICALWIDTH For printing devices: the width of the physical page, in device units. For example, a printer set to print at 600 dpi on 8.5"x11" paper has a physical width value of 5100 device units. Note that the physical page is almost always greater than the printable area of the page, and never smaller.
PHYSICALHEIGHT For printing devices: the height of the physical page, in device units. For example, a printer set to print at 600 dpi on 8.5"x11" paper has a physical height value of 6600 device units. Note that the physical page is almost always greater than the printable area of the page, and never smaller.
PHYSICALOFFSETX For printing devices: the distance from the left edge of the physical page to the left edge of the printable area, in device units. For example, a printer set to print at 600 dpi on 8.5"x11" paper, that cannot print on the leftmost 0.25" of paper, has a horizontal physical offset of 150 device units.
PHYSICALOFFSETY For printing devices: the distance from the top edge of the physical page to the top edge of the printable area, in device units. For example, a printer set to print at 600 dpi on 8.5"x11" paper, that cannot print on the topmost 0.5" of paper, has a vertical physical offset of 300 device units.
VREFRESH Windows NT only: For display devices: the current vertical refresh rate of the device, in cycles per second (Hz).

A vertical refresh rate value of 0 or 1 represents the display hardware's default refresh rate. This default rate is typically set by switches on a display card or computer motherboard, or by a configuration program that does not use Win32 display functions such as ChangeDisplaySettings.

DESKTOPHORZRES Windows NT only: Width, in pixels, of the virtual desktop. This value may be larger than HORZRES if the device supports a virtual desktop or multiple displays.
DESKTOPVERTRES Windows NT only: Height, in pixels, of the virtual desktop. This value may be larger than VERTRES if the device supports a virtual desktop or multiple displays.
BLTALIGNMENT Windows NT only: Preferred horizontal drawing alignment, expressed as a multiple of pixels. For best drawing performance, windows should be horizontally aligned to a multiple of this value. A value of zero indicates that the device is accelerated, and any alignment may be used.
RASTERCAPS Value that indicates the raster capabilities of the device, as shown in the following table:

Capability Meaning
RC_BANDING Requires banding support.
RC_BITBLT Capable of transferring bitmaps.
RC_BITMAP64 Capable of supporting bitmaps larger than 64K.
RC_DI_BITMAP Capable of supporting the SetDIBits and GetDIBits functions.
RC_DIBTODEV Capable of supporting the SetDIBitsToDevice function.
RC_FLOODFILL Capable of performing flood fills.
RC_GDI20_OUTPUT Capable of supporting features of Windows 2.0.
RC_PALETTE Specifies a palette-based device.
RC_SCALING Capable of scaling.
RC_STRETCHBLT Capable of performing the StretchBlt function.
RC_STRETCHDIB Capable of performing the StretchDIBits function.

CURVECAPS Value that indicates the curve capabilities of the device, as shown in the following table:

Value Meaning
CC_NONE Device does not support curves.
CC_CIRCLES Device can draw circles.
CC_PIE Device can draw pie wedges.
CC_CHORD Device can draw chord arcs.
CC_ELLIPSES Device can draw ellipses.
CC_WIDE Device can draw wide borders.
CC_STYLED Device can draw styled borders.
CC_WIDESTYLED Device can draw borders that are wide and styled.
CC_INTERIORS Device can draw interiors.
CC_ROUNDRECT Device can draw rounded rectangles.

LINECAPS Value that indicates the line capabilities of the device, as shown in the following table:

Value Meaning
LC_NONE Device does not support lines.
LC_POLYLINE Device can draw a polyline.
LC_MARKER Device can draw a marker.
LC_POLYMARKER Device can draw multiple markers.
LC_WIDE Device can draw wide lines.
LC_STYLED Device can draw styled lines.
LC_WIDESTYLED Device can draw lines that are wide and styled.
LC_INTERIORS Device can draw interiors.

POLYGONALCAPS Value that indicates the polygon capabilities of the device, as shown in the following table:

Value Meaning
PC_NONE Device does not support polygons.
PC_POLYGON Device can draw alternate-fill polygons.
PC_RECTANGLE Device can draw rectangles.
PC_WINDPOLYGON Device can draw winding-fill polygons.
PC_SCANLINE Device can draw a single scanline.
PC_WIDE Device can draw wide borders.
PC_STYLED Device can draw styled borders.
PC_WIDESTYLED Device can draw borders that are wide and styled.
PC_INTERIORS Device can draw interiors.

TEXTCAPS Value that indicates the text capabilities of the device, as shown in the following table:

Bit Meaning
TC_OP_CHARACTER Device is capable of character output precision.
TC_OP_STROKE Device is capable of stroke output precision.
TC_CP_STROKE Device is capable of stroke clip precision.
TC_CR_90 Device is capable of 90-degree character rotation.
TC_CR_ANY Device is capable of any character rotation.
TC_SF_X_YINDEP Device can scale independently in the x- and y-directions.
TC_SA_DOUBLE Device is capable of doubled character for scaling.
TC_SA_INTEGER Device uses integer multiples only for character scaling.
TC_SA_CONTIN Device uses any multiples for exact character scaling.
TC_EA_DOUBLE Device can draw double-weight characters.
TC_IA_ABLE Device can italicize.
TC_UA_ABLE Device can underline.
TC_SO_ABLE Device can draw strikeouts.
TC_RA_ABLE Device can draw raster fonts.
TC_VA_ABLE Device can draw vector fonts.
TC_RESERVED Reserved; must be zero.
TC_SCROLLBLT Device cannot scroll using a bit-block transfer. Note that this meaning may be the opposite of what you expect.

Return Values

The return value specifies the value of the desired item.

See Also

CreateEnhMetaFile, CreateIC, DeviceCapabilities, GetDIBits, GetObjectType, SetDIBits, SetDIBitsToDevice, StretchBlt, StretchDIBits