OffsetPoly

OffsetPoly
Header:	Quickdraw.h		Carbon status:	Supported

Moves a polygon.

void OffsetPoly (
    PolyHandle poly, 
    SInt16 dh, 
    SInt16 dv
);

Parameter descriptions

poly: A handle to a polygon to move.
dh: The horizontal distance to move the polygon.
dv: The vertical distance to move the polygon.

DISCUSSION

The OffsetPoly function moves the polygon whose handle you pass in the poly parameter by adding the value you specify in the dh parameter to the horizontal coordinates of its points, and by adding the value you specify in the dv parameter to the vertical coordinates of all points of its region boundary. If the values of dh and dv are positive, the movement is to the right and down; if either is negative, the corresponding movement is in the opposite direction. The region retains its size and shape. This does not affect the screen unless you subsequently call a function to draw the region.

OffsetPoly is an especially efficient operation, because the data defining a polygon is stored relative to the first point of the polygon and so is not actually changed by OffsetPoly.

AVAILABILITY

Supported in Carbon. Available in Carbon 1.0.2 and later when running Mac OS 8.1 or later.