GetDeviceCaps
2.x
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int GetDeviceCaps(hdc, iCapability) |
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HDC hdc; |
/* handle of device context |
*/ |
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int iCapability; |
/* index of capability to query |
*/ |
The GetDeviceCaps function retrieves device-specific information about a given display device.
Parameters
hdc
Identifies the device context.
iCapability
Specifies the type of information to be returned. It can be one of the following indices:
| DRIVERVERSION |
Version number of the device driver. |
| TECHNOLOGY |
Device technology. It can be one of the following values: |
| 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 |
| HORZSIZE |
Width of the physical display, in millimeters. |
| VERTSIZE |
Height of the physical display, in millimeters. |
| HORZRES |
Width of the display, in pixels. |
| VERTRES |
Height of the display, in raster lines. |
| LOGPIXELSX |
Number of pixels per logical inch along the display width. |
| LOGPIXELSY |
Number of pixels per logical inch along the display 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. |
| NUMMARKERS |
Number of device-specific markers. |
| NUMFONTS |
Number of device-specific fonts. |
| NUMCOLORS |
Number of entries in the device's color table. |
| Index |
Description |
| 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 a device pixel used for line drawing. |
| PDEVICESIZE |
Size of the PDEVICE internal structure, in bytes. |
| CLIPCAPS |
Clipping capabilities the device supports. It can be one of the following values: |
| Value |
Meaning |
| CP_NONE |
Output is not clipped. |
| CP_RECTANGLE |
Output is clipped to rectangles. |
| CP_REGION |
Output is clipped to regions. |
| 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; it is available only if the driver is written for Windows 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; it is available only if the driver is written for Windows 3.0 or later. |
| COLORRES |
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; it is available only if the driver is written for Windows 3.0 or later. |
| RASTERCAPS |
Raster capabilities the device supports. It can be a combination of the following values: |
| Value |
Meaning |
| RC_BANDING |
Supports banding. |
| RC_BIGFONT |
Supports fonts larger than 64K. |
| RC_BITBLT |
Transfers bitmaps. |
| RC_BITMAP64 |
Supports bitmaps larger than 64K. |
| RC_DEVBITS |
Supports device bitmaps. |
| RC_DI_BITMAP |
Supports the SetDIBits and GetDIBits functions. |
| RC_DIBTODEV |
Supports the SetDIBitsToDevice function. |
| RC_FLOODFILL |
Performs flood fills. |
| RC_GDI20_OUTPUT |
Supports Windows version 2.0 features. |
| Index |
Description |
| RC_GDI20_STATE |
Includes a state block in the device context. |
| RC_NONE |
Supports no raster operations. |
| RC_OP_DX_OUTPUT |
Supports dev opaque and DX array. |
| RC_PALETTE |
Specifies a palette-based device. |
| RC_SAVEBITMAP |
Saves bitmaps locally. |
| RC_SCALING |
Supports scaling. |
| RC_STRETCHBLT |
Supports the StretchBlt function. |
| RC_STRETCHDIB |
Supports the StretchDIBits function. |
| CURVECAPS |
Curve capabilities the device supports. It can be a combination of the following values: |
| Value |
Meaning |
| CC_NONE |
Supports curves. |
| CC_CIRCLES |
Supports circles. |
| CC_PIE |
Supports pie wedges. |
| CC_CHORD |
Supports chords. |
| CC_ELLIPSES |
Supports ellipses. |
| CC_WIDE |
Supports wide borders. |
| CC_STYLED |
Supports styled borders. |
| CC_WIDESTYLED |
Supports wide, styled borders. |
| CC_INTERIORS |
Supports interiors. |
| CC_ROUNDRECT |
Supports rectangles with rounded corners. |
| LINECAPS |
Line capabilities the device supports. It can be a combination of the following values: |
| Value |
Meaning |
| LC_NONE |
Supports no lines. |
| LC_POLYLINE |
Supports polylines. |
| LC_MARKER |
Supports markers. |
| LC_POLYMARKER |
Supports polymarkers. |
| Index |
Description |
| LC_WIDE |
Supports wide lines. |
| LC_STYLED |
Supports styled lines. |
| LC_WIDESTYLED |
Supports wide, styled lines. |
| LC_INTERIORS |
Supports interiors. |
| POLYGONALCAPS |
Polygonal capabilities the device supports. It can be a combination of the following values: |
| Value |
Meaning |
| PC_NONE |
Supports no polygons. |
| PC_POLYGON |
Supports alternate fill polygons. |
| PC_RECTANGLE |
Supports rectangles. |
| PC_WINDPOLYGON |
Supports winding number fill polygons. |
| PC_SCANLINE |
Supports scan lines. |
| PC_WIDE |
Supports wide borders. |
| PC_STYLED |
Supports styled borders. |
| PC_WIDESTYLED |
Supports wide, styled borders. |
| PC_INTERIORS |
Supports interiors. |
| TEXTCAPS |
Text capabilities the device supports. It can be a combination of the following values: |
| Value |
Meaning |
| TC_OP_CHARACTER |
Supports character output precision, which indicates the device can place device fonts at any pixel location. This is required for any device with device fonts. |
| TC_OP_STROKE |
Supports stroke output precision, which indicates the device can omit any stroke of a device font. |
| TC_CP_STROKE |
Supports stroke clip precision, which indicates the device can clip device fonts to a pixel boundary. |
| Index |
Description |
| TC_CR_90 |
Supports 90-degree character rotation, which indicates the device can rotate characters only 90 degrees at a time. |
| TC_CR_ANY |
Supports character rotation at any degree, which indicates the device can rotate device fonts through any angle. |
| TC_SF_X_YINDEP |
Supports scaling independent of x and y directions, which indicates the device can scale device fonts separately in x and y directions. |
| TC_SA_DOUBLE |
Supports doubled characters for scaling, which indicates the device can double the size of device fonts. |
| TC_SA_INTEGER |
Supports integer multiples for scaling, which indicates the device can scale the size of device fonts in any integer multiple. |
| TC_SA_CONTIN |
Supports any multiples for exact scaling, which indicates the device can scale device fonts by any amount but still preserve the x and y ratios. |
| TC_EA_DOUBLE |
Supports double-weight characters, which indicates the device can make device fonts bold. If this bit is not set for printer drivers, graphics device interface (GDI) attempts to create bold device fonts by printing them twice. |
| TC_IA_ABLE |
Supports italics, which indicates the device can make device fonts italic. If this bit is not set, GDI assumes italics are not available. |
| Index |
Description |
| TC_UA_ABLE |
Supports underlining, which indicates the device can underline device fonts. If this bit is not set, GDI creates underlines for device fonts. |
| TC_SO_ABLE |
Supports strikeouts, which indicates the device can strikeout device fonts. If this bit is not set, GDI creates strikeouts for device fonts. |
| TC_RA_ABLE |
Supports raster fonts, which indicates that GDI should enumerate any raster or TrueType fonts available for this device in response to a call to the EnumFonts or EnumFontFamilies function. If this bit is not set, GDI-supplied raster or TrueType fonts are not enumerated when these functions are called. |
| TC_VA_ABLE |
Supports vector fonts, which indicates that GDI should enumerate any vector fonts available for this device in response to a call to the EnumFonts or EnumFontFamilies function. This is significant for vector devices only (that is, for plotters). Display drivers (which must be able to use raster fonts) and raster printer drivers always enumerate vector fonts, because GDI rasterizes vector fonts before sending them to the driver. |
| TC_RESERVED |
Reserved; must be zero. |
Return Value
The return value is the value of the requested capability if the function is successful.
Example
The following example uses the GetDeviceCaps function to determine whether a device supports raster capabilities and is palette-based. If so, the example calls the GetSystemPaletteUse function.
WORD nUse;
hdc = GetDC(hwnd);
if ((GetDeviceCaps(hdc, RASTERCAPS) & RC_PALETTE) == 0) {
ReleaseDC(hwnd, hdc);
break;
}
nUse = GetSystemPaletteUse(hdc);
ReleaseDC(hwnd, hdc);