Back to index...

	/*
	* Copyright (c) 2007, 2013, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package sun.java2d.pisces;

	import java.awt.Shape;
	import java.awt.BasicStroke;
	import java.awt.geom.Path2D;
	import java.awt.geom.AffineTransform;
	import java.awt.geom.PathIterator;

	import sun.awt.geom.PathConsumer2D;
	import sun.java2d.pipe.Region;
	import sun.java2d.pipe.RenderingEngine;
	import sun.java2d.pipe.AATileGenerator;

	public class PiscesRenderingEngine extends RenderingEngine {
	private static enum NormMode {OFF, ON_NO_AA, ON_WITH_AA}

	/**
	* Create a widened path as specified by the parameters.
	* <p>
	* The specified {@code src} {@link Shape} is widened according
	* to the specified attribute parameters as per the
	* {@link BasicStroke} specification.
	*
	* @param src the source path to be widened
	* @param width the width of the widened path as per {@code BasicStroke}
	* @param caps the end cap decorations as per {@code BasicStroke}
	* @param join the segment join decorations as per {@code BasicStroke}
	* @param miterlimit the miter limit as per {@code BasicStroke}
	* @param dashes the dash length array as per {@code BasicStroke}
	* @param dashphase the initial dash phase as per {@code BasicStroke}
	* @return the widened path stored in a new {@code Shape} object
	* @since 1.7
	*/
	public Shape createStrokedShape(Shape src,
	float width,
	int caps,
	int join,
	float miterlimit,
	float dashes[],
	float dashphase)
	{
	final Path2D p2d = new Path2D.Float();

	strokeTo(src,
	null,
	width,
	NormMode.OFF,
	caps,
	join,
	miterlimit,
	dashes,
	dashphase,
	new PathConsumer2D() {
	public void moveTo(float x0, float y0) {
	p2d.moveTo(x0, y0);
	}
	public void lineTo(float x1, float y1) {
	p2d.lineTo(x1, y1);
	}
	public void closePath() {
	p2d.closePath();
	}
	public void pathDone() {}
	public void curveTo(float x1, float y1,
	float x2, float y2,
	float x3, float y3) {
	p2d.curveTo(x1, y1, x2, y2, x3, y3);
	}
	public void quadTo(float x1, float y1, float x2, float y2) {
	p2d.quadTo(x1, y1, x2, y2);
	}
	public long getNativeConsumer() {
	throw new InternalError("Not using a native peer");
	}
	});
	return p2d;
	}

	/**
	* Sends the geometry for a widened path as specified by the parameters
	* to the specified consumer.
	* <p>
	* The specified {@code src} {@link Shape} is widened according
	* to the parameters specified by the {@link BasicStroke} object.
	* Adjustments are made to the path as appropriate for the
	* {@link VALUE_STROKE_NORMALIZE} hint if the {@code normalize}
	* boolean parameter is true.
	* Adjustments are made to the path as appropriate for the
	* {@link VALUE_ANTIALIAS_ON} hint if the {@code antialias}
	* boolean parameter is true.
	* <p>
	* The geometry of the widened path is forwarded to the indicated
	* {@link PathConsumer2D} object as it is calculated.
	*
	* @param src the source path to be widened
	* @param bs the {@code BasicSroke} object specifying the
	* decorations to be applied to the widened path
	* @param normalize indicates whether stroke normalization should
	* be applied
	* @param antialias indicates whether or not adjustments appropriate
	* to antialiased rendering should be applied
	* @param consumer the {@code PathConsumer2D} instance to forward
	* the widened geometry to
	* @since 1.7
	*/
	public void strokeTo(Shape src,
	AffineTransform at,
	BasicStroke bs,
	boolean thin,
	boolean normalize,
	boolean antialias,
	final PathConsumer2D consumer)
	{
	NormMode norm = (normalize) ?
	((antialias) ? NormMode.ON_WITH_AA : NormMode.ON_NO_AA)
	: NormMode.OFF;
	strokeTo(src, at, bs, thin, norm, antialias, consumer);
	}

	void strokeTo(Shape src,
	AffineTransform at,
	BasicStroke bs,
	boolean thin,
	NormMode normalize,
	boolean antialias,
	PathConsumer2D pc2d)
	{
	float lw;
	if (thin) {
	if (antialias) {
	lw = userSpaceLineWidth(at, 0.5f);
	} else {
	lw = userSpaceLineWidth(at, 1.0f);
	}
	} else {
	lw = bs.getLineWidth();
	}
	strokeTo(src,
	at,
	lw,
	normalize,
	bs.getEndCap(),
	bs.getLineJoin(),
	bs.getMiterLimit(),
	bs.getDashArray(),
	bs.getDashPhase(),
	pc2d);
	}

	private float userSpaceLineWidth(AffineTransform at, float lw) {

	double widthScale;

	if ((at.getType() & (AffineTransform.TYPE_GENERAL_TRANSFORM \|
	AffineTransform.TYPE_GENERAL_SCALE)) != 0) {
	widthScale = Math.sqrt(at.getDeterminant());
	} else {
	/* First calculate the "maximum scale" of this transform. */
	double A = at.getScaleX(); // m00
	double C = at.getShearX(); // m01
	double B = at.getShearY(); // m10
	double D = at.getScaleY(); // m11

	/*
	* Given a 2 x 2 affine matrix [ A B ] such that
	* [ C D ]
	* v' = [x' y'] = [Ax + Cy, Bx + Dy], we want to
	* find the maximum magnitude (norm) of the vector v'
	* with the constraint (x^2 + y^2 = 1).
	* The equation to maximize is
	* \|v'\| = sqrt((Ax+Cy)^2+(Bx+Dy)^2)
	* or \|v'\| = sqrt((AA+BB)x^2 + 2(AC+BD)xy + (CC+DD)y^2).
	* Since sqrt is monotonic we can maximize \|v'\|^2
	* instead and plug in the substitution y = sqrt(1 - x^2).
	* Trigonometric equalities can then be used to get
	* rid of most of the sqrt terms.
	*/

	double EA = AA + BB; // x^2 coefficient
	double EB = 2(AC + B*D); // xy coefficient
	double EC = CC + DD; // y^2 coefficient

	/*
	* There is a lot of calculus omitted here.
	*
	* Conceptually, in the interests of understanding the
	* terms that the calculus produced we can consider
	* that EA and EC end up providing the lengths along
	* the major axes and the hypot term ends up being an
	* adjustment for the additional length along the off-axis
	* angle of rotated or sheared ellipses as well as an
	* adjustment for the fact that the equation below
	* averages the two major axis lengths. (Notice that
	* the hypot term contains a part which resolves to the
	* difference of these two axis lengths in the absence
	* of rotation.)
	*
	* In the calculus, the ratio of the EB and (EA-EC) terms
	* ends up being the tangent of 2*theta where theta is
	* the angle that the long axis of the ellipse makes
	* with the horizontal axis. Thus, this equation is
	* calculating the length of the hypotenuse of a triangle
	* along that axis.
	*/

	double hypot = Math.sqrt(EBEB + (EA-EC)(EA-EC));
	/* sqrt omitted, compare to squared limits below. */
	double widthsquared = ((EA + EC + hypot)/2.0);

	widthScale = Math.sqrt(widthsquared);
	}

	return (float) (lw / widthScale);
	}

	void strokeTo(Shape src,
	AffineTransform at,
	float width,
	NormMode normalize,
	int caps,
	int join,
	float miterlimit,
	float dashes[],
	float dashphase,
	PathConsumer2D pc2d)
	{
	// We use strokerat and outat so that in Stroker and Dasher we can work only
	// with the pre-transformation coordinates. This will repeat a lot of
	// computations done in the path iterator, but the alternative is to
	// work with transformed paths and compute untransformed coordinates
	// as needed. This would be faster but I do not think the complexity
	// of working with both untransformed and transformed coordinates in
	// the same code is worth it.
	// However, if a path's width is constant after a transformation,
	// we can skip all this untransforming.

	// If normalization is off we save some transformations by not
	// transforming the input to pisces. Instead, we apply the
	// transformation after the path processing has been done.
	// We can't do this if normalization is on, because it isn't a good
	// idea to normalize before the transformation is applied.
	AffineTransform strokerat = null;
	AffineTransform outat = null;

	PathIterator pi = null;

	if (at != null && !at.isIdentity()) {
	final double a = at.getScaleX();
	final double b = at.getShearX();
	final double c = at.getShearY();
	final double d = at.getScaleY();
	final double det = a * d - c * b;
	if (Math.abs(det) <= 2 * Float.MIN_VALUE) {
	// this rendering engine takes one dimensional curves and turns
	// them into 2D shapes by giving them width.
	// However, if everything is to be passed through a singular
	// transformation, these 2D shapes will be squashed down to 1D
	// again so, nothing can be drawn.

	// Every path needs an initial moveTo and a pathDone. If these
	// are not there this causes a SIGSEGV in libawt.so (at the time
	// of writing of this comment (September 16, 2010)). Actually,
	// I am not sure if the moveTo is necessary to avoid the SIGSEGV
	// but the pathDone is definitely needed.
	pc2d.moveTo(0, 0);
	pc2d.pathDone();
	return;
	}

	// If the transform is a constant multiple of an orthogonal transformation
	// then every length is just multiplied by a constant, so we just
	// need to transform input paths to stroker and tell stroker
	// the scaled width. This condition is satisfied if
	// ab == -cd && aa+cc == bb+dd. In the actual check below, we
	// leave a bit of room for error.
	if (nearZero(ab + cd, 2) && nearZero(aa+cc - (bb+dd), 2)) {
	double scale = Math.sqrt(aa + cc);
	if (dashes != null) {
	dashes = java.util.Arrays.copyOf(dashes, dashes.length);
	for (int i = 0; i < dashes.length; i++) {
	dashes[i] = (float)(scale * dashes[i]);
	}
	dashphase = (float)(scale * dashphase);
	}
	width = (float)(scale * width);
	pi = src.getPathIterator(at);
	if (normalize != NormMode.OFF) {
	pi = new NormalizingPathIterator(pi, normalize);
	}
	// by now strokerat == null && outat == null. Input paths to
	// stroker (and maybe dasher) will have the full transform at
	// applied to them and nothing will happen to the output paths.
	} else {
	if (normalize != NormMode.OFF) {
	strokerat = at;
	pi = src.getPathIterator(at);
	pi = new NormalizingPathIterator(pi, normalize);
	// by now strokerat == at && outat == null. Input paths to
	// stroker (and maybe dasher) will have the full transform at
	// applied to them, then they will be normalized, and then
	// the inverse of only the non translation part of at will
	// be applied to the normalized paths. This won't cause problems
	// in stroker, because, suppose at = T*A, where T is just the
	// translation part of at, and A is the rest. T*A has already
	// been applied to Stroker/Dasher's input. Then Ainv will be
	// applied. AinvTA is not equal to T, but it is a translation,
	// which means that none of stroker's assumptions about its
	// input will be violated. After all this, A will be applied
	// to stroker's output.
	} else {
	outat = at;
	pi = src.getPathIterator(null);
	// outat == at && strokerat == null. This is because if no
	// normalization is done, we can just apply all our
	// transformations to stroker's output.
	}
	}
	} else {
	// either at is null or it's the identity. In either case
	// we don't transform the path.
	pi = src.getPathIterator(null);
	if (normalize != NormMode.OFF) {
	pi = new NormalizingPathIterator(pi, normalize);
	}
	}

	// by now, at least one of outat and strokerat will be null. Unless at is not
	// a constant multiple of an orthogonal transformation, they will both be
	// null. In other cases, outat == at if normalization is off, and if
	// normalization is on, strokerat == at.
	pc2d = TransformingPathConsumer2D.transformConsumer(pc2d, outat);
	pc2d = TransformingPathConsumer2D.deltaTransformConsumer(pc2d, strokerat);
	pc2d = new Stroker(pc2d, width, caps, join, miterlimit);
	if (dashes != null) {
	pc2d = new Dasher(pc2d, dashes, dashphase);
	}
	pc2d = TransformingPathConsumer2D.inverseDeltaTransformConsumer(pc2d, strokerat);
	pathTo(pi, pc2d);
	}

	private static boolean nearZero(double num, int nulps) {
	return Math.abs(num) < nulps * Math.ulp(num);
	}

	private static class NormalizingPathIterator implements PathIterator {

	private final PathIterator src;

	// the adjustment applied to the current position.
	private float curx_adjust, cury_adjust;
	// the adjustment applied to the last moveTo position.
	private float movx_adjust, movy_adjust;

	// constants used in normalization computations
	private final float lval, rval;

	NormalizingPathIterator(PathIterator src, NormMode mode) {
	this.src = src;
	switch (mode) {
	case ON_NO_AA:
	// round to nearest (0.25, 0.25) pixel
	lval = rval = 0.25f;
	break;
	case ON_WITH_AA:
	// round to nearest pixel center
	lval = 0f;
	rval = 0.5f;
	break;
	case OFF:
	throw new InternalError("A NormalizingPathIterator should " +
	"not be created if no normalization is being done");
	default:
	throw new InternalError("Unrecognized normalization mode");
	}
	}

	public int currentSegment(float[] coords) {
	int type = src.currentSegment(coords);

	int lastCoord;
	switch(type) {
	case PathIterator.SEG_CUBICTO:
	lastCoord = 4;
	break;
	case PathIterator.SEG_QUADTO:
	lastCoord = 2;
	break;
	case PathIterator.SEG_LINETO:
	case PathIterator.SEG_MOVETO:
	lastCoord = 0;
	break;
	case PathIterator.SEG_CLOSE:
	// we don't want to deal with this case later. We just exit now
	curx_adjust = movx_adjust;
	cury_adjust = movy_adjust;
	return type;
	default:
	throw new InternalError("Unrecognized curve type");
	}

	// normalize endpoint
	float x_adjust = (float)Math.floor(coords[lastCoord] + lval) +
	rval - coords[lastCoord];
	float y_adjust = (float)Math.floor(coords[lastCoord+1] + lval) +
	rval - coords[lastCoord + 1];

	coords[lastCoord ] += x_adjust;
	coords[lastCoord + 1] += y_adjust;

	// now that the end points are done, normalize the control points
	switch(type) {
	case PathIterator.SEG_CUBICTO:
	coords[0] += curx_adjust;
	coords[1] += cury_adjust;
	coords[2] += x_adjust;
	coords[3] += y_adjust;
	break;
	case PathIterator.SEG_QUADTO:
	coords[0] += (curx_adjust + x_adjust) / 2;
	coords[1] += (cury_adjust + y_adjust) / 2;
	break;
	case PathIterator.SEG_LINETO:
	break;
	case PathIterator.SEG_MOVETO:
	movx_adjust = x_adjust;
	movy_adjust = y_adjust;
	break;
	case PathIterator.SEG_CLOSE:
	throw new InternalError("This should be handled earlier.");
	}
	curx_adjust = x_adjust;
	cury_adjust = y_adjust;
	return type;
	}

	public int currentSegment(double[] coords) {
	float[] tmp = new float[6];
	int type = this.currentSegment(tmp);
	for (int i = 0; i < 6; i++) {
	coords[i] = (float) tmp[i];
	}
	return type;
	}

	public int getWindingRule() {
	return src.getWindingRule();
	}

	public boolean isDone() {
	return src.isDone();
	}

	public void next() {
	src.next();
	}
	}

	static void pathTo(PathIterator pi, PathConsumer2D pc2d) {
	RenderingEngine.feedConsumer(pi, pc2d);
	pc2d.pathDone();
	}

	/**
	* Construct an antialiased tile generator for the given shape with
	* the given rendering attributes and store the bounds of the tile
	* iteration in the bbox parameter.
	* The {@code at} parameter specifies a transform that should affect
	* both the shape and the {@code BasicStroke} attributes.
	* The {@code clip} parameter specifies the current clip in effect
	* in device coordinates and can be used to prune the data for the
	* operation, but the renderer is not required to perform any
	* clipping.
	* If the {@code BasicStroke} parameter is null then the shape
	* should be filled as is, otherwise the attributes of the
	* {@code BasicStroke} should be used to specify a draw operation.
	* The {@code thin} parameter indicates whether or not the
	* transformed {@code BasicStroke} represents coordinates smaller
	* than the minimum resolution of the antialiasing rasterizer as
	* specified by the {@code getMinimumAAPenWidth()} method.
	* <p>
	* Upon returning, this method will fill the {@code bbox} parameter
	* with 4 values indicating the bounds of the iteration of the
	* tile generator.
	* The iteration order of the tiles will be as specified by the
	* pseudo-code:
	* <pre>
	* for (y = bbox[1]; y < bbox[3]; y += tileheight) {
	* for (x = bbox[0]; x < bbox[2]; x += tilewidth) {
	* }
	* }
	* </pre>
	* If there is no output to be rendered, this method may return
	* null.
	*
	* @param s the shape to be rendered (fill or draw)
	* @param at the transform to be applied to the shape and the
	* stroke attributes
	* @param clip the current clip in effect in device coordinates
	* @param bs if non-null, a {@code BasicStroke} whose attributes
	* should be applied to this operation
	* @param thin true if the transformed stroke attributes are smaller
	* than the minimum dropout pen width
	* @param normalize true if the {@code VALUE_STROKE_NORMALIZE}
	* {@code RenderingHint} is in effect
	* @param bbox returns the bounds of the iteration
	* @return the {@code AATileGenerator} instance to be consulted
	* for tile coverages, or null if there is no output to render
	* @since 1.7
	*/
	public AATileGenerator getAATileGenerator(Shape s,
	AffineTransform at,
	Region clip,
	BasicStroke bs,
	boolean thin,
	boolean normalize,
	int bbox[])
	{
	Renderer r;
	NormMode norm = (normalize) ? NormMode.ON_WITH_AA : NormMode.OFF;
	if (bs == null) {
	PathIterator pi;
	if (normalize) {
	pi = new NormalizingPathIterator(s.getPathIterator(at), norm);
	} else {
	pi = s.getPathIterator(at);
	}
	r = new Renderer(3, 3,
	clip.getLoX(), clip.getLoY(),
	clip.getWidth(), clip.getHeight(),
	pi.getWindingRule());
	pathTo(pi, r);
	} else {
	r = new Renderer(3, 3,
	clip.getLoX(), clip.getLoY(),
	clip.getWidth(), clip.getHeight(),
	PathIterator.WIND_NON_ZERO);
	strokeTo(s, at, bs, thin, norm, true, r);
	}
	r.endRendering();
	PiscesTileGenerator ptg = new PiscesTileGenerator(r, r.MAX_AA_ALPHA);
	ptg.getBbox(bbox);
	return ptg;
	}

	public AATileGenerator getAATileGenerator(double x, double y,
	double dx1, double dy1,
	double dx2, double dy2,
	double lw1, double lw2,
	Region clip,
	int bbox[])
	{
	// REMIND: Deal with large coordinates!
	double ldx1, ldy1, ldx2, ldy2;
	boolean innerpgram = (lw1 > 0 && lw2 > 0);

	if (innerpgram) {
	ldx1 = dx1 * lw1;
	ldy1 = dy1 * lw1;
	ldx2 = dx2 * lw2;
	ldy2 = dy2 * lw2;
	x -= (ldx1 + ldx2) / 2.0;
	y -= (ldy1 + ldy2) / 2.0;
	dx1 += ldx1;
	dy1 += ldy1;
	dx2 += ldx2;
	dy2 += ldy2;
	if (lw1 > 1 && lw2 > 1) {
	// Inner parallelogram was entirely consumed by stroke...
	innerpgram = false;
	}
	} else {
	ldx1 = ldy1 = ldx2 = ldy2 = 0;
	}

	Renderer r = new Renderer(3, 3,
	clip.getLoX(), clip.getLoY(),
	clip.getWidth(), clip.getHeight(),
	PathIterator.WIND_EVEN_ODD);

	r.moveTo((float) x, (float) y);
	r.lineTo((float) (x+dx1), (float) (y+dy1));
	r.lineTo((float) (x+dx1+dx2), (float) (y+dy1+dy2));
	r.lineTo((float) (x+dx2), (float) (y+dy2));
	r.closePath();

	if (innerpgram) {
	x += ldx1 + ldx2;
	y += ldy1 + ldy2;
	dx1 -= 2.0 * ldx1;
	dy1 -= 2.0 * ldy1;
	dx2 -= 2.0 * ldx2;
	dy2 -= 2.0 * ldy2;
	r.moveTo((float) x, (float) y);
	r.lineTo((float) (x+dx1), (float) (y+dy1));
	r.lineTo((float) (x+dx1+dx2), (float) (y+dy1+dy2));
	r.lineTo((float) (x+dx2), (float) (y+dy2));
	r.closePath();
	}

	r.pathDone();

	r.endRendering();
	PiscesTileGenerator ptg = new PiscesTileGenerator(r, r.MAX_AA_ALPHA);
	ptg.getBbox(bbox);
	return ptg;
	}

	/**
	* Returns the minimum pen width that the antialiasing rasterizer
	* can represent without dropouts occurring.
	* @since 1.7
	*/
	public float getMinimumAAPenSize() {
	return 0.5f;
	}

	static {
	if (PathIterator.WIND_NON_ZERO != Renderer.WIND_NON_ZERO \|\|
	PathIterator.WIND_EVEN_ODD != Renderer.WIND_EVEN_ODD \|\|
	BasicStroke.JOIN_MITER != Stroker.JOIN_MITER \|\|
	BasicStroke.JOIN_ROUND != Stroker.JOIN_ROUND \|\|
	BasicStroke.JOIN_BEVEL != Stroker.JOIN_BEVEL \|\|
	BasicStroke.CAP_BUTT != Stroker.CAP_BUTT \|\|
	BasicStroke.CAP_ROUND != Stroker.CAP_ROUND \|\|
	BasicStroke.CAP_SQUARE != Stroker.CAP_SQUARE)
	{
	throw new InternalError("mismatched renderer constants");
	}
	}
	}

Back to index...