OpenPoly

Start recording a polygon definition

#include <Quickdraw.h> Quickdraw

PolyHandle OpenPoly( );

OpenPoly allocates and initializes an empty Polygon structure. It hides the

pen. The endpoints of subsequent Line and LineTo operations are recorded

into the polygon's data structure until you stop the recording via ClosePoly.

Returns: a PolyHandle; a handle to a variable-length Polygon structure that

is allocated and initialized by this call. The polySize field is set to 10

and the polyBBox field is set to the empty rectangle (0,0)(0,0).

Notes: This call begins accumulating the definition of a polygon by recording the

endpoints of the line segments drawn with Line and LineTo. Upon stopping

recording (see ClosePoly), the polygon should be a series of connected

lines:

Unlike OpenRgn, this call allocates the handle and data structure for you.

However, many other features are similar:

• The pen is hidden (unless a previous call to ShowPen has not been

balanced) and you can use ShowPen after opening the picture if you want

to see the pen while drawing.

• Don't open another Polygon or Region when one is already open.

• To temporarily interrupt polygon-definition recording, you can switch to

a different GrafPort (see SetPort), or you can save the current value of

polySave, and set it to NIL. Restore the saved value to resume recording.

Polygons are limited to 32K bytes (8192 vertices). Use GetHandleSize

to track the size of an open polygon as it grows. After the polygon is closed,

you can read its size directly by accessing the polySize field of the Polygon

structure.

The following example creates a triangular polygon, fills it, then discards

it.

Example

#include <Quickdraw.h>

PolyHandle thePoly;

thePoly = OpenPoly( ); „/* start recording */

MoveTo( 100,100 ); „/* start and end point */

LineTo( 50,200 ); „/* left side */

LineTo(150,200 ); „/* bottom */

LineTo(100,100 ); „/* right side */

ClosePoly(); [TOKEN:12074] stop recording */

FillPoly( thePoly, black ); /* fill inside */

KillPoly( thePoly ); „/* deallocate all memory used here */