DrvQueryFontCaps function (winddi.h)

Article
02/22/2024

The DrvQueryFontCaps function defines the capabilities of the font driver.

Syntax

LONG DrvQueryFontCaps(
  ULONG culCaps,
  ULONG *pulCaps
);

Parameters

culCaps

Specifies the number of ULONG values in the array pointed to by the pulCaps parameter that can be written by the font driver.

pulCaps

Pointer to an array that receives the number of values specified in the first parameter. The elements of the array have the following meanings:

Element	Meaning
pulCaps[0]	A count of the number of ULONG values in the complete array. If culCaps is less than this value, then the caller will receive an incomplete array.
pulCaps[1]	A set of flags that can be one or more of the following values: QC_OUTLINES If this flag is set, the font driver can return an outline description of the glyphs. Moreover, the fonts are assumed to be scalable. Bitmap fonts do not have this flag set. QC_1BIT Indicates that the font driver is capable of returning monochrome bitmaps of each glyph. QC_4BIT Indicates that the font driver is capable of returning antialiased 4-bits-per-pixel bitmaps. Each pixel in the bitmap is represented by an unsigned 4-bit value in the range 0 through 15, yielding 16 shades of gray.

Element

Meaning

pulCaps[0]

A count of the number of ULONG values in the complete array. If culCaps is less than this value, then the caller will receive an incomplete array.

pulCaps[1]

A set of flags that can be one or more of the following values:

QC_OUTLINES
If this flag is set, the font driver can return an outline description of the glyphs. Moreover, the fonts are assumed to be scalable. Bitmap fonts do not have this flag set.

QC_1BIT
Indicates that the font driver is capable of returning monochrome bitmaps of each glyph.

QC_4BIT
Indicates that the font driver is capable of returning antialiased 4-bits-per-pixel bitmaps. Each pixel in the bitmap is represented by an unsigned 4-bit value in the range 0 through 15, yielding 16 shades of gray.

Return value

The return value is the number of ULONG values written to the destination buffer if the function is successful. Otherwise, it is FD_ERROR.

Remarks

A driver might report that it supports more than one format for a font. For example, a driver could, in principle, return with both QC_1BIT and QC_4BIT set, indicating that it is capable of returning both monochrome and antialiased versions of the font. All bitmaps generated by a font driver must start and end on 32-bit boundaries. If necessary, the end of a bitmap should be "padded" to satisfy this requirement.

Requirements

Requirement	Value
Target Platform	Desktop
Header	winddi.h (include Winddi.h)