DevQueryCaps (1.2)
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#define INCL_DEV
BOOL DevQueryCaps(hdc, lStartitem, cItems, alItems)
HDC hdc; /* device-context handle */
LONG lStartitem; /* first item to be returned */
LONG cItems; /* number of items to be returned */
PLONG alItems; /* array for device characteristics */
The DevQueryCaps function queries the characteristics of the specified
device.
Parameter Description
────────────────────────────────────────────────────────────────────────────
hdc Identifies the device context.
lStartitem Specifies the first item of information to be returned in the
array.
cItems Specifies the number of items to be returned in the array.
alItems Points to an array of device characteristics, starting with the
item specified by the lStartitem parameter.
Return Value
The return value is TRUE if the function is successful or FALSE if an error
occurs.
Errors
Use the WinGetLastError function to retrieve the error value, which may be
one of the following:
PMERR_INV_HDC
PMERR_INV_LENGTH_OR_COUNT
PMERR_INV_QUERY_ELEMENT_NO
Comments
The following are possible values for the alItems parameter:
Value Meaning
────────────────────────────────────────────────────────────────────────────
CAPS_FAMILY Specifies the device type. These values are the
same as the values for the type parameter in
the DevOpenDC function.
CAPS_IO_CAPS Specifies the device input/output capability.
The possible values are as follows:
Value Meaning
───────────────────────────────────────────────
CAPS_IO_DUMMY Dummy device
CAPS_IO_SUPPORTS_OP Output
CAPS_IO_SUPPORTS_IP Input
CAPS_IO_SUPPORTS_IO Output and input
CAPS_TECHNOLOGY Specifies the technology. The possible values
are as follows:
Value Meaning
───────────────────────────────────────────────
CAPS_TECH_UNKNOWN Unknown (for example,
metafile)
CAPS_TECH_VECTOR_PLOTTER Vector plotter
CAPS_TECH_RASTER_DISPLAY Raster display
CAPS_TECH_RASTER_PRINTER Raster printer
CAPS_TECH_RASTER_CAMERA Raster camera
CAPS_TECH_POSTSCRIPT PostScript printer
CAPS_DRIVER_VERSION Specifies the device-driver version number.
CAPS_HEIGHT Specifies the media depth (for a full-screen,
maximized window on a display) in pels. (For a
plotter, a pel is defined as the smallest
possible displacement of the pen and can be
smaller than a pen width.)
CAPS_WIDTH Specifies the media width (for a full-screen,
maximized window for displays) in pels.
CAPS_HEIGHT_IN_CHARS Specifies the media depth (for a full-screen,
maximized window for displays) in character
rows, for Vio calls only.
CAPS_WIDTH_IN_CHARS Specifies the media width (for a full-screen,
maximized window for displays) in character
columns, for Vio calls only.
CAPS_HORIZONTAL_FONT_RES Specifies the horizontal resolution (in pels
per inch) for printers; for displays, this
value may differ from the actual horizontal
device resolution.
CAPS_VERTICAL_FONT_RES Specifies the vertical resolution (in pels per
inch) for printers; for displays, this value
may differ from the actual vertical device
resolution.
CAPS_VERTICAL_RESOLUTION Specifies the vertical resolution (in pels per
meter) of the device.
CAPS_HORIZONTAL_RESOLUTION Specifies the horizontal resolution (in pels
per meter) of the device.
CAPS_CHAR_HEIGHT Specifies the default height (in pels) of the
character box.
CAPS_CHAR_WIDTH Specifies the default width (in pels) of the
character box.
CAPS_SMALL_CHAR_HEIGHT Specifies the default height (in pels) of the
small character box. This number is zero if
there is only one size of the character box.
CAPS_SMALL_CHAR_WIDTH Specifies the default width (in pels) of the
small character box. This number is zero if
there is only one size of the character box.
CAPS_COLORS Specifies the number of distinct colors
supported at the same time, including reset
(gray-scales count as distinct colors). If
loadable color tables are supported, this is
the number of entries in the device color
table. For plotters, the value returned is the
number of pens plus one (for the background).
CAPS_MOUSE_BUTTONS Specifies the number of mouse or tablet buttons
that are available. A returned value of zero
indicates that there are no mouse or tablet
buttons available.
CAPS_FOREGROUND_MIX_SUPPORT Specifies the foreground-mix support. The
possible values are as follows:
Value Meaning
───────────────────────────────────────────────
CAPS_FM_OR OR
CAPS_FM_OVERPAINT Overpaint
CAPS_FM_XOR XOR
CAPS_FM_LEAVEALONE Leave-alone
CAPS_FM_AND AND
CAPS_FM_GENERAL_BOOLEAN Mixes 7 through 17
The value returned is the sum of the values
appropriate to the mixes supported. A device
capable of supporting the OR mix mode must, as
a minimum, return 1 + 2 + 16 = 19, signifying
support for the mandatory mix modes OR,
overpaint, and leave-alone. Note that these
numbers correspond to the decimal
representation of a bit string that is seven
bits long, with each bit set to 1 if the
appropriate mode is supported.
CAPS_BACKGROUND_MIX_SUPPORT Specifies the background-mix support. The
possible values are as follows:
Value Meaning
───────────────────────────────────────────────
CAPS_BM_OR OR
CAPS_BM_OVERPAINT Overpaint
CAPS_BM_XOR XOR
CAPS_BM_LEAVEALONE Leave-alone
The value returned is the sum of the values
appropriate to the mixes supported. A device
must, as a minimum, return 2 + 16 = 18,
signifying support for the mandatory background
mixes overpaint and leave-alone. Note that
these numbers correspond to the decimal
representation of a bit string that is five
bits long, with each bit set to 1 if the
appropriate mode is supported.
CAPS_LOADABLE_SYMBOL_SETS Specifies the number of fonts that may be
loaded for Vio.
CAPS_WINDOW_BYTE_ALIGNMENT Specifies whether the client area of VIO
windows should be byte-aligned. The possible
values are as follows:
Value Meaning
───────────────────────────────────────────────
CAPS_BYTE_ALIGN_REQUIRED Must be
byte-aligned.
CAPS_BYTE_ALIGN_RECOMMENDED More efficient if
byte-aligned, but
not required.
CAPS_BYTE_ALIGN_NOT_REQUIRED Does not matter
whether
byte-aligned.
CAPS_BITMAP_FORMATS Specifies the number of bitmap formats
supported by the device.
CAPS_RASTER_CAPS Specifies the raster-operations capability of
the device. The possible values are as
follows:
Value Meaning
───────────────────────────────────────────────
CAPS_RASTER_BITBLT BitBlt supported
CAPS_RASTER_BANDING Banding supported
CAPS_RASTER_BITBLT_SCALING Scaling supported
CAPS_RASTER_SET_PEL Set PEL support
CAPS_MARKER_WIDTH Specifies the default width (in pels) of the
marker box.
CAPS_MARKER_HEIGHT Specifies the default depth (in pels) of the
marker box.
CAPS_DEVICE_FONTS Specifies the number of device-specific fonts.
CAPS_GRAPHICS_SUBSET Specifies the graphics-drawing subset supported
(3 indicates GOCA DR/3).
CAPS_GRAPHICS_VERSION Specifies the graphics-architecture version
supported (1 indicates version 1).
CAPS_GRAPHICS_VECTOR_SUBSET Specifies the graphics-vector-drawing subset
supported (2 indicates GOCA VS/2).
CAPS_GRAPHICS_CHAR_WIDTH Specifies the default Gpi character-box width
(in pels).
CAPS_GRAPHICS_CHAR_HEIGHT Specifies the default Gpi character-box height
(in pels).
CAPS_DEVICE_WINDOWING Specifies the support for device windows. This
value may be CAPS_DEV_WINDOWING_SUPPORT if the
device supports windowing.
CAPS_ADDITIONAL_GRAPHICS Specifies additional graphics support. The
possible values are as follows:
Value Meaning
───────────────────────────────────────────────
CAPS_GRAPHICS_KERNING_SUPPORT The device
supports
kerning.
CAPS_FONT_OUTLINE_DEFAULT Outline font is
the default.
CAPS_FONT_IMAGE_DEFAULT Font image is
the default.
CAPS_SCALED_DEFAULT_MARKERS Scaled default
markers.
CAPS_RESERVED Specifies the maximum number of distinct colors
available at one time.
CAPS_PHYS_COLORS Specifies the maximum number of distinct colors
that can be specified on the device.
CAPS_COLOR_INDEX Specifies the maximum logical-color-table index
supported for the device. This value must be at
least 7. For the EGA and VGA device drivers,
the value is 63.
CAPS_COLOR_PLANES Specifies the number of color planes.
CAPS_COLOR_BITCOUNT Specifies the number of adjacent color bits for
each pel (within one plane).
CAPS_COLOR_TABLE_SUPPORT Specifies the support for loadable color
tables. It can be one of the following values:
Value Meaning
───────────────────────────────────────────────
CAPS_COLTABL_RGB_8 Set if the RGB color
table can be loaded,
with a minimum
support of 8 bits
each for red, green,
and blue.
CAPS_COLTABLE_RGB_8_PLUS Set if a color table
with other than 8
bits for each primary
color can be loaded.
CAPS_COLTABLE_TRUE_MIX Set if true mixing
occurs when the
logical color table
has been realized,
providing that the
size of the logical
color table is not
greater than the
number of distinct
colors supported (see
CAPS_COLORS).
CAPS_COLTABL_REALIZE Set if a loaded color
table can be
realized.
See Also
DevOpenDC
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