GetPath
The GetPath
function retrieves the coordinates defining the endpoints of lines and the
control points of curves found in the path that is selected into the specified
device context.
int GetPath(
|
HDC hdc, |
// handle of device
context |
|
LPPOINT lpPoints, |
// address of array
receiving path vertices |
|
LPBYTE lpTypes, |
// address of array
of path vertex types |
|
int nSize |
// count of points
defining path |
|
); |
|
Parameters
hdc
Identifies a
device context that contains a closed path.
lpPoints
Points to an
array of POINT
structures that contains the line endpoints and curve control points.
lpTypes
Points to an
array of bytes where the vertex types are placed. Values are one of the
following:
|
Type |
Description |
|
PT_MOVETO |
Specifies
that the corresponding point in the lpPoints parameter starts a
disjoint figure. |
|
PT_LINETO |
Specifies
that the previous point and the corresponding point in lpPoints are
the endpoints of a line. |
|
PT_BEZIERTO |
Specifies
that the corresponding point in lpPoints is a control point or ending
point for a B zier curve. |
|
|
PT_BEZIERTO
values always occur in sets of three. The point in the path immediately
preceding them defines the starting point for the B zier curve. The first two
PT_BEZIERTO points are the control points, and the third PT_BEZIERTO point is
the ending (if hard-coded) point. |
A PT_LINETO
or PT_BEZIERTO value may be combined with the following value (by using the
bitwise operator OR) to indicate that the corresponding point is the last point
in a figure and the figure should be closed:
|
Flag |
Description |
|
PT_CLOSEFIGURE |
Specifies
that the figure is automatically closed after the corresponding line or curve
is drawn. The figure is closed by drawing a line from the line or curve
endpoint to the point corresponding to the last PT_MOVETO. |
nSize
Specifies the
total number of POINT structures that may be placed in the array pointed
to by lpPoints. This value must be the same as the number of bytes that
may be placed in the array pointed to by lpTypes.
Return Values
If the nSize
parameter is nonzero, the return value is the number of points enumerated. If nSize
is 0, the return value is the total number of points in the path (and GetPath
writes nothing to the buffers). If nSize is nonzero and is less than the
number of points in the path, the return value is -1. To get extended error information, call GetLastError. GetLastError may
return one of the following error codes:
ERROR_CAN_NOT_COMPLETE
ERROR_INVALID_PARAMETER
ERROR_BUFFER_OVERFLOW
Remarks
The device
context identified by the hdc parameter must contain a closed path.
The points of
the path are returned in logical coordinates. Points are stored in the path in
device coordinates, so GetPath changes the points from device
coordinates to logical coordinates by using the inverse of the current
transformation.
The FlattenPath
function may be called before GetPath to convert all curves in the path
into line segments.
See Also