File	Doc	Category	Size	Date	Package
FlatteningPathIterator.java	API Doc	Java SE 5 API	11911	Fri Aug 26 14:56:52 BST 2005	java.awt.geom

FlatteningPathIterator

• java.lang.Object

Fields Summary
static final int	GROW_SIZE
PathIterator	src
double	squareflat
int	limit
double[]	hold
double	curx
double	cury
double	movx
double	movy
int	holdType
int	holdEnd
int	holdIndex
int[]	levels
int	levelIndex
boolean	done

Constructors Summary
public FlatteningPathIterator(PathIterator src, double flatness) Constructs a new FlatteningPathIterator object that flattens a path as it iterates over it. The iterator does not subdivide any curve read from the source iterator to more than 10 levels of subdivision which yields a maximum of 1024 line segments per curve. param src the original unflattened path being iterated over param flatness the maximum allowable distance between the control points and the flattened curve // True when iteration is done this(src, flatness, 10);
public FlatteningPathIterator(PathIterator src, double flatness, int limit) Constructs a new FlatteningPathIterator object that flattens a path as it iterates over it. The limit parameter allows you to control the maximum number of recursive subdivisions that the iterator can make before it assumes that the curve is flat enough without measuring against the flatness parameter. The flattened iteration therefore never generates more than a maximum of (2^limit) line segments per curve. param src the original unflattened path being iterated over param flatness the maximum allowable distance between the control points and the flattened curve param limit the maximum number of recursive subdivisions allowed for any curved segment exception IllegalArgumentException if flatness or limit is less than zero if (flatness < 0.0) { throw new IllegalArgumentException("flatness must be >= 0"); } if (limit < 0) { throw new IllegalArgumentException("limit must be >= 0"); } this.src = src; this.squareflat = flatness * flatness; this.limit = limit; this.levels = new int[limit + 1]; // prime the first path segment next(false);

Methods Summary
public int	currentSegment(float[] coords) Returns the coordinates and type of the current path segment in the iteration. The return value is the path segment type: SEG_MOVETO, SEG_LINETO, or SEG_CLOSE. A float array of length 6 must be passed in and can be used to store the coordinates of the point(s). Each point is stored as a pair of float x,y coordinates. SEG_MOVETO and SEG_LINETO types return one point, and SEG_CLOSE does not return any points. param coords an array that holds the data returned from this method return the path segment type of the current path segment. exception NoSuchElementException if there are no more elements in the flattening path to be returned. see PathIterator#SEG_MOVETO see PathIterator#SEG_LINETO see PathIterator#SEG_CLOSE if (isDone()) { throw new NoSuchElementException("flattening iterator out of bounds"); } int type = holdType; if (type != SEG_CLOSE) { coords[0] = (float) hold[holdIndex + 0]; coords[1] = (float) hold[holdIndex + 1]; if (type != SEG_MOVETO) { type = SEG_LINETO; } } return type;
public int	currentSegment(double[] coords) Returns the coordinates and type of the current path segment in the iteration. The return value is the path segment type: SEG_MOVETO, SEG_LINETO, or SEG_CLOSE. A double array of length 6 must be passed in and can be used to store the coordinates of the point(s). Each point is stored as a pair of double x,y coordinates. SEG_MOVETO and SEG_LINETO types return one point, and SEG_CLOSE does not return any points. param coords an array that holds the data returned from this method return the path segment type of the current path segment. exception NoSuchElementException if there are no more elements in the flattening path to be returned. see PathIterator#SEG_MOVETO see PathIterator#SEG_LINETO see PathIterator#SEG_CLOSE if (isDone()) { throw new NoSuchElementException("flattening iterator out of bounds"); } int type = holdType; if (type != SEG_CLOSE) { coords[0] = hold[holdIndex + 0]; coords[1] = hold[holdIndex + 1]; if (type != SEG_MOVETO) { type = SEG_LINETO; } } return type;
void	ensureHoldCapacity(int want) if (holdIndex - want < 0) { int have = hold.length - holdIndex; int newsize = hold.length + GROW_SIZE; double newhold[] = new double[newsize]; System.arraycopy(hold, holdIndex, newhold, holdIndex + GROW_SIZE, have); hold = newhold; holdIndex += GROW_SIZE; holdEnd += GROW_SIZE; }
public double	getFlatness() Returns the flatness of this iterator. return the flatness of this FlatteningPathIterator. return Math.sqrt(squareflat);
public int	getRecursionLimit() Returns the recursion limit of this iterator. return the recursion limit of this FlatteningPathIterator. return limit;
public int	getWindingRule() Returns the winding rule for determining the interior of the path. return the winding rule of the original unflattened path being iterated over. see PathIterator#WIND_EVEN_ODD see PathIterator#WIND_NON_ZERO return src.getWindingRule();
public boolean	isDone() Tests if the iteration is complete. return true if all the segments have been read; false otherwise. return done;
public void	next() Moves the iterator to the next segment of the path forwards along the primary direction of traversal as long as there are more points in that direction. next(true);
private void	next(boolean doNext) int level; if (holdIndex >= holdEnd) { if (doNext) { src.next(); } if (src.isDone()) { done = true; return; } holdType = src.currentSegment(hold); levelIndex = 0; levels[0] = 0; } switch (holdType) { case SEG_MOVETO: case SEG_LINETO: curx = hold[0]; cury = hold[1]; if (holdType == SEG_MOVETO) { movx = curx; movy = cury; } holdIndex = 0; holdEnd = 0; break; case SEG_CLOSE: curx = movx; cury = movy; holdIndex = 0; holdEnd = 0; break; case SEG_QUADTO: if (holdIndex >= holdEnd) { // Move the coordinates to the end of the array. holdIndex = hold.length - 6; holdEnd = hold.length - 2; hold[holdIndex + 0] = curx; hold[holdIndex + 1] = cury; hold[holdIndex + 2] = hold[0]; hold[holdIndex + 3] = hold[1]; hold[holdIndex + 4] = curx = hold[2]; hold[holdIndex + 5] = cury = hold[3]; } level = levels[levelIndex]; while (level < limit) { if (QuadCurve2D.getFlatnessSq(hold, holdIndex) < squareflat) { break; } ensureHoldCapacity(4); QuadCurve2D.subdivide(hold, holdIndex, hold, holdIndex - 4, hold, holdIndex); holdIndex -= 4; // Now that we have subdivided, we have constructed // two curves of one depth lower than the original // curve. One of those curves is in the place of // the former curve and one of them is in the next // set of held coordinate slots. We now set both // curves level values to the next higher level. level++; levels[levelIndex] = level; levelIndex++; levels[levelIndex] = level; } // This curve segment is flat enough, or it is too deep // in recursion levels to try to flatten any more. The // two coordinates at holdIndex+4 and holdIndex+5 now // contain the endpoint of the curve which can be the // endpoint of an approximating line segment. holdIndex += 4; levelIndex--; break; case SEG_CUBICTO: if (holdIndex >= holdEnd) { // Move the coordinates to the end of the array. holdIndex = hold.length - 8; holdEnd = hold.length - 2; hold[holdIndex + 0] = curx; hold[holdIndex + 1] = cury; hold[holdIndex + 2] = hold[0]; hold[holdIndex + 3] = hold[1]; hold[holdIndex + 4] = hold[2]; hold[holdIndex + 5] = hold[3]; hold[holdIndex + 6] = curx = hold[4]; hold[holdIndex + 7] = cury = hold[5]; } level = levels[levelIndex]; while (level < limit) { if (CubicCurve2D.getFlatnessSq(hold, holdIndex) < squareflat) { break; } ensureHoldCapacity(6); CubicCurve2D.subdivide(hold, holdIndex, hold, holdIndex - 6, hold, holdIndex); holdIndex -= 6; // Now that we have subdivided, we have constructed // two curves of one depth lower than the original // curve. One of those curves is in the place of // the former curve and one of them is in the next // set of held coordinate slots. We now set both // curves level values to the next higher level. level++; levels[levelIndex] = level; levelIndex++; levels[levelIndex] = level; } // This curve segment is flat enough, or it is too deep // in recursion levels to try to flatten any more. The // two coordinates at holdIndex+6 and holdIndex+7 now // contain the endpoint of the curve which can be the // endpoint of an approximating line segment. holdIndex += 6; levelIndex--; break; }