CDC::GetGlyphOutline

DWORD GetGlyphOutline( UINT nChar, UINT nFormat, LPGLYPHMETRICS lpgm, DWORD cbBuffer, LPVOID lpBuffer, const MAT2 FAR* lpmat2 ) const;

Return Value

The size, in bytes, of the buffer required for the retrieved information if cbBuffer is 0 or lpBuffer is NULL. Otherwise, it is a positive value if the function is successful, or –1 if there is an error.

Parameters

nChar

Specifies the character for which information is to be returned.

nFormat

Specifies the format in which the function is to return information. It can be one of the following values, or 0:

Value	Meaning
GGO_BITMAP	Returns the glyph bitmap. When the function returns, the buffer pointed to by lpBuffer contains a 1-bit-per-pixel bitmap whose rows start on doubleword boundaries.
GGO_NATIVE	Returns the curve data points in the rasterizer’s native format, using device units. When this value is specified, any transformation specified in lpmat2 is ignored.

When the value of nFormat is 0, the function fills in a GLYPHMETRICS structure but does not return glyph-outline data.

lpgm

Points to a GLYPHMETRICS structure that describes the placement of the glyph in the character cell.

cbBuffer

Specifies the size of the buffer into which the function copies information about the outline character. If this value is 0 and the nFormat parameter is either the GGO_BITMAP or GGO_NATIVE values, the function returns the required size of the buffer.

lpBuffer

Points to a buffer into which the function copies information about the outline character. If nFormat specifies the GGO_NATIVE value, the information is copied in the form of TTPOLYGONHEADER and TTPOLYCURVE structures. If this value is NULL and nFormat is either the GGO_BITMAP or GGO_NATIVE value, the function returns the required size of the buffer.

lpmat2

Points to a MAT2 structure that contains a transformation matrix for the character. This parameter cannot be NULL, even when the GGO_NATIVE value is specified for nFormat.

Remarks

Retrieves the outline curve or bitmap for an outline character in the current font.

An application can rotate characters retrieved in bitmap format by specifying a 2-by-2 transformation matrix in the structure pointed to by lpmat2.

A glyph outline is returned as a series of contours. Each contour is defined by a TTPOLYGONHEADER structure followed by as many TTPOLYCURVE structures as are required to describe it. All points are returned as POINTFX structures and represent absolute positions, not relative moves. The starting point given by the pfxStart member of the TTPOLYGONHEADER structure is the point at which the outline for a contour begins. The TTPOLYCURVE structures that follow can be either polyline records or spline records. Polyline records are a series of points; lines drawn between the points describe the outline of the character. Spline records represent the quadratic curves used by TrueType (that is, quadratic b-splines).

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