PolygonPen.mesa

Michael Plass, May 11, 1984 10:11:06 am PDT

DIRECTORY

This module provides for the conversion of pen-drawn spline curves to spline-bounded outlines. The simplest kind of pen handled here is the broad pen, which is just a line segment. Polygonal-pen strokes are built up by means of multiple broad-pen strokes.

PolygonPen: CEDAR DEFINITIONS ~

BEGIN

Vec: TYPE ~ GraphicsBasic.Vec;

Bezier: TYPE ~ RECORD[b0, b1, b2, b3: Vec];

Pen: TYPE ~ REF PenRec;

PenRec: TYPE ~ RECORD[point: SEQUENCE n: NAT OF Vec];

a broad pen is represented as a vector, with the reference point at the origin.

The results are sent by calling procedures of the following types:

MoveToProc: TYPE ~ PROCEDURE [z0: Vec];

LineToProc: TYPE ~ PROCEDURE [z1: Vec];

CurveToProc: TYPE ~ PROCEDURE [z1, z2, z3: Vec]; -- three Bezier control points. z3 is the new last point.

SimpleStroke: PROCEDURE [pen: Vec, curve: Bezier, moveTo: MoveToProc, lineTo: LineToProc, curveTo: CurveToProc]; -- for when the interior of the curve is known never to be parallel to the pen

BroadStroke: PROCEDURE [pen: Vec, curve: Bezier, moveTo: MoveToProc, lineTo: LineToProc, curveTo: CurveToProc]; -- for a compound stroke with a broad pen.

Dot: PROCEDURE [pen: Pen, point: Vec, moveTo: MoveToProc, lineTo: LineToProc, curveTo: CurveToProc];

Line: PROCEDURE [pen: Pen, startPoint, endPoint: Vec, moveTo: MoveToProc, lineTo: LineToProc, curveTo: CurveToProc];

Stroke: PROCEDURE [pen: Pen, curve: Bezier, moveTo: MoveToProc, lineTo: LineToProc, curveTo: CurveToProc];

END.