SetPolyFillMode
The SetPolyFillMode
function sets the polygon fill mode for functions that fill polygons.
int SetPolyFillMode(
|
HDC hdc, |
// handle of device
context |
|
int iPolyFillMode |
// polygon fill
mode |
|
); |
|
Parameters
hdc
Identifies
the device context.
iPolyFillMode
Specifies the
new fill mode. This parameter can be either of the following values:
|
Value |
Meaning |
|
ALTERNATE |
Selects
alternate mode (fills the area between odd-numbered and even-numbered polygon
sides on each scan line). |
|
WINDING |
Selects
winding mode (fills any region with a nonzero winding value). |
Return Values
The return
value specifies the previous filling mode. If an error occurs, the return value
is zero.
Remarks
In general,
the modes differ only in cases where a complex, overlapping polygon must be
filled (for example, a five-sided polygon that forms a five-pointed star with a
pentagon in the center). In such cases, ALTERNATE mode fills every other
enclosed region within the polygon (that is, the points of the star), but
WINDING mode fills all regions (that is, the points and the pentagon).
When the fill
mode is ALTERNATE, GDI fills the area between odd-numbered and even-numbered
polygon sides on each scan line. That is, GDI fills the area between the first
and second side, between the third and fourth side, and so on.
When the fill
mode is WINDING, GDI fills any region that has a nonzero winding value. This
value is defined as the number of times a pen used to draw the polygon would go
around the region. The direction of each edge of the polygon is important.
See Also