edu.mit.blocks.codeblocks.rendering

Class BevelIterator

java.lang.Object

edu.mit.blocks.codeblocks.rendering.BevelIterator

public class BevelIterator
extends java.lang.Object

The BevelIterator class handles the geometry calculations involved in creating a bevel effect around the edge of a shape. Like a FlatteningPathIterator, it iterates over a set of line segments that follows the shape's boundary. For each segment it provides four points, of which the 2nd and 3rd are the endpoints of the current segment, and the 1st and 4th are the endpoints of the neighboring segments. From these four points relevant vectors for drawing a bevel are automatically calculated and provided.

Points and vectors are specified by (x,y) coordinates in an array.

Author:

David Greenspan

See Also:

PathIterator

Field Summary

Fields

Modifier and Type	Field and Description
float[]	inset2 a vector pointing inwards from pt2, bisecting the angle at that point, scaled to have a length appropriate for a bevel of thickness 1.0 (in other words, lying on the line that is parallel to the current segment and a distance of 1.0 inwards).
float[]	inset3 a vector pointing inwards from pt3, bisecting the angle at that point, scaled to have a length appropriate for a bevel of thickness 1.0 (in other words, lying on the line that is parallel to the current segment and a distance of 1.0 inwards).
float[]	perpVec a unit vector perpendicular to the current segment, pointing outwards
float[]	pt1 the point that comes before the current segment's start-point
float[]	pt2 the start-point of the current segment
float[]	pt3 the end-point of the current segment
float[]	pt4 the point that comes after the current segment's end-point

Constructor Summary

Constructors

Constructor and Description
BevelIterator(java.awt.Shape area, double flatness) Constructs a BevelIterator for a given shape.

Method Summary

Modifier and Type	Method and Description
float[]	insetPoint2(float scalar, float[] f) Scales the vector inset2 by the factor scalar and adds it to pt2.
float[]	insetPoint3(float scalar, float[] f) Scales the vector inset3 by the factor scalar and adds it to pt3.
boolean	isDone() Returns true if a call to nextSegment will move to a new segment.
void	nextSegment() Fills in this class's fields with information about the next segment.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

pt1

public float[] pt1

the point that comes before the current segment's start-point

pt2

public float[] pt2

the start-point of the current segment

pt3

public float[] pt3

the end-point of the current segment

pt4

public float[] pt4

the point that comes after the current segment's end-point

inset2

public float[] inset2

a vector pointing inwards from pt2, bisecting the angle at that point, scaled to have a length appropriate for a bevel of thickness 1.0 (in other words, lying on the line that is parallel to the current segment and a distance of 1.0 inwards).

inset3

public float[] inset3

a vector pointing inwards from pt3, bisecting the angle at that point, scaled to have a length appropriate for a bevel of thickness 1.0 (in other words, lying on the line that is parallel to the current segment and a distance of 1.0 inwards).

perpVec

public float[] perpVec

a unit vector perpendicular to the current segment, pointing outwards

Constructor Detail

BevelIterator

public BevelIterator(java.awt.Shape area,
                     double flatness)

Constructs a BevelIterator for a given shape. The shape should be simply-connected and have a boundary that does not intersect itself. The flatness parameter has the same meaning as in the constructor of FlatteningPathIterator. The fields of this class are undefined until nextSegment is first called.

Parameters:

area - the region whose boundary is to be beveled

flatness - the maximum allowable distance by which the segments can deviate from the actual boundary

Method Detail

nextSegment

public void nextSegment()

Fills in this class's fields with information about the next segment. Has no effect if all segments have been encountered.

isDone

public boolean isDone()

Returns true if a call to nextSegment will move to a new segment.

Returns:

whether all segments have been encountered

insetPoint2

public float[] insetPoint2(float scalar,
                           float[] f)

Scales the vector inset2 by the factor scalar and adds it to pt2. The returned point is pt2 inset by an amount appropriate for a bevel of thickness scalar.

Parameters:

scalar - amount to scale inset2 by

f - receives the new point

Returns:

the argument f

insetPoint3

public float[] insetPoint3(float scalar,
                           float[] f)

Scales the vector inset3 by the factor scalar and adds it to pt3. The returned point is pt3 inset by an amount appropriate for a bevel of thickness scalar.

Parameters:

scalar - amount to scale inset3 by

f - receives the new point

Returns:

the argument f