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native-prism.Stroker.c Maven / Gradle / Ivy
/*
* Copyright (c) 2012, 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.
*/
#include
#include
#include
#include
#include "Helpers.h"
#include "PathConsumer.h"
#include "Stroker.h"
// NOTE: some of the arithmetic here is too verbose and prone to hard to
// debug typos. We should consider making a small Point/Vector class that
// has methods like plus(Point), minus(Point), dot(Point), cross(Point)and such
//public final class Stroker implements PathConsumer2D {
#define MOVE_TO 0
#define DRAWING_OP_TO 1 // ie. curve, line, or quad
#define CLOSE 2
static MoveToFunc Stroker_moveTo;
static LineToFunc Stroker_lineTo;
static QuadToFunc Stroker_quadTo;
static CurveToFunc Stroker_curveTo;
static ClosePathFunc Stroker_closePath;
static PathDoneFunc Stroker_pathDone;
#define this (*((Stroker *) pStroker))
static void drawJoin(PathConsumer *pStroker,
jfloat pdx, jfloat pdy,
jfloat x0, jfloat y0,
jfloat dx, jfloat dy,
jfloat omx, jfloat omy,
jfloat mx, jfloat my);
static void drawRoundJoin2(PathConsumer *pStroker,
jfloat cx, jfloat cy,
jfloat omx, jfloat omy,
jfloat mx, jfloat my,
jboolean rev);
static void drawBezApproxForArc(PathConsumer *pStroker,
const jfloat cx, const jfloat cy,
const jfloat omx, const jfloat omy,
const jfloat mx, const jfloat my,
jboolean rev);
static void emitMoveTo(PathConsumer *pStroker, const jfloat x0, const jfloat y0);
static void emitLineTo(PathConsumer *pStroker, const jfloat x1, const jfloat y1,
const jboolean rev);
static void emitCurveTo(PathConsumer *pStroker,
const jfloat x0, const jfloat y0,
const jfloat x1, const jfloat y1,
const jfloat x2, const jfloat y2,
const jfloat x3, const jfloat y3, const jboolean rev);
static void emitClose(PathConsumer *pStroker);
static void emitReverse(PathConsumer *pStroker);
static void finish(PathConsumer *pStroker);
extern void PolyStack_init(PolyStack *pStack);
extern void PolyStack_destroy(PolyStack *pStack);
extern jboolean PolyStack_isEmpty(PolyStack *pStack);
extern void PolyStack_pushLine(PolyStack *pStack,
jfloat x, jfloat y);
extern void PolyStack_pushCubic(PolyStack *pStack,
jfloat x0, jfloat y0,
jfloat x1, jfloat y1,
jfloat x2, jfloat y2);
extern void PolyStack_pushQuad(PolyStack *pStack,
jfloat x0, jfloat y0,
jfloat x1, jfloat y1);
extern void PolyStack_pop(PolyStack *pStack, PathConsumer *io);
/**
* Constructs a Stroker.
*
* @param pc2d an output PathConsumer2D.
* @param lineWidth the desired line width in pixels
* @param capStyle the desired end cap style, one of
* CAP_BUTT, CAP_ROUND or
* CAP_SQUARE.
* @param joinStyle the desired line join style, one of
* JOIN_MITER, JOIN_ROUND or
* JOIN_BEVEL.
* @param miterLimit the desired miter limit
public Stroker(PathConsumer2D pc2d,
float lineWidth,
jint capStyle,
jint joinStyle,
float miterLimit)
{
this(pc2d);
reset(lineWidth, capStyle, joinStyle, miterLimit);
}
public Stroker(PathConsumer2D pc2d) {
setConsumer(pc2d);
}
public void setConsumer(PathConsumer2D pc2d) {
this.out = pc2d;
}
*/
extern void Stroker_reset(Stroker *pStroker, jfloat lineWidth,
jint capStyle, jint joinStyle, jfloat miterLimit);
void Stroker_init(Stroker *pStroker,
PathConsumer *out,
jfloat lineWidth,
jint capStyle,
jint joinStyle,
jfloat miterLimit)
{
memset(pStroker, 0, sizeof(Stroker));
PathConsumer_init(&this.consumer,
Stroker_moveTo,
Stroker_lineTo,
Stroker_quadTo,
Stroker_curveTo,
Stroker_closePath,
Stroker_pathDone);
this.out = out;
Stroker_reset(pStroker, lineWidth, capStyle, joinStyle, miterLimit);
PolyStack_init(&pStroker->reverse);
}
void Stroker_reset(Stroker *pStroker, jfloat lineWidth,
jint capStyle, jint joinStyle, jfloat miterLimit)
{
jfloat limit;
this.lineWidth2 = lineWidth / 2;
this.capStyle = capStyle;
this.joinStyle = joinStyle;
limit = miterLimit * this.lineWidth2;
this.miterLimitSq = limit*limit;
this.prev = CLOSE;
}
void Stroker_destroy(Stroker *pStroker) {
PolyStack_destroy(&pStroker->reverse);
}
void computeOffset(const jfloat lx, const jfloat ly,
const jfloat w, jfloat m[])
{
const jfloat len = (jfloat) sqrt(lx*lx + ly*ly);
if (len == 0) {
m[0] = m[1] = 0;
} else {
m[0] = (ly * w)/len;
m[1] = -(lx * w)/len;
}
}
// Returns true if the vectors (dx1, dy1) and (dx2, dy2) are
// clockwise (if dx1,dy1 needs to be rotated clockwise to close
// the smallest angle between it and dx2,dy2).
// This is equivalent to detecting whether a point q is on the right side
// of a line passing through points p1, p2 where p2 = p1+(dx1,dy1) and
// q = p2+(dx2,dy2), which is the same as saying p1, p2, q are in a
// clockwise order.
// NOTE: "clockwise" here assumes coordinates with 0,0 at the bottom left.
static jboolean isCW(const jfloat dx1, const jfloat dy1,
const jfloat dx2, const jfloat dy2)
{
return dx1 * dy2 <= dy1 * dx2;
}
// pisces used to use fixed point arithmetic with 16 decimal digits. I
// didn't want to change the values of the constant below when I converted
// it to floating point, so that's why the divisions by 2^16 are there.
#define ROUND_JOIN_THRESHOLD (1000/65536.0f)
static void drawRoundJoin(PathConsumer *pStroker,
jfloat x, jfloat y,
jfloat omx, jfloat omy, jfloat mx, jfloat my,
jboolean rev,
jfloat threshold)
{
jfloat domx, domy, len;
if ((omx == 0 && omy == 0) || (mx == 0 && my == 0)) {
return;
}
domx = omx - mx;
domy = omy - my;
len = domx*domx + domy*domy;
if (len < threshold) {
return;
}
if (rev) {
omx = -omx;
omy = -omy;
mx = -mx;
my = -my;
}
drawRoundJoin2(pStroker, x, y, omx, omy, mx, my, rev);
}
static void drawRoundJoin2(PathConsumer *pStroker,
jfloat cx, jfloat cy,
jfloat omx, jfloat omy,
jfloat mx, jfloat my,
jboolean rev)
{
// The sign of the dot product of mx,my and omx,omy is equal to the
// the sign of the cosine of ext
// (ext is the angle between omx,omy and mx,my).
jdouble cosext = omx * mx + omy * my;
// If it is >=0, we know that abs(ext) is <= 90 degrees, so we only
// need 1 curve to approximate the circle section that joins omx,omy
// and mx,my.
const jint numCurves = cosext >= 0 ? 1 : 2;
switch (numCurves) {
case 1:
drawBezApproxForArc(pStroker, cx, cy, omx, omy, mx, my, rev);
break;
case 2:
{
// we need to split the arc into 2 arcs spanning the same angle.
// The point we want will be one of the 2 intersections of the
// perpendicular bisector of the chord (omx,omy)->(mx,my) and the
// circle. We could find this by scaling the vector
// (omx+mx, omy+my)/2 so that it has length=lineWidth2 (and thus lies
// on the circle), but that can have numerical problems when the angle
// between omx,omy and mx,my is close to 180 degrees. So we compute a
// normal of (omx,omy)-(mx,my). This will be the direction of the
// perpendicular bisector. To get one of the intersections, we just scale
// this vector that its length is lineWidth2 (this works because the
// perpendicular bisector goes through the origin). This scaling doesn't
// have numerical problems because we know that lineWidth2 divided by
// this normal's length is at least 0.5 and at most sqrt(2)/2 (because
// we know the angle of the arc is > 90 degrees).
jfloat nx = my - omy, ny = omx - mx;
jfloat nlen = (jfloat) sqrt(nx*nx + ny*ny);
jfloat scale = this.lineWidth2/nlen;
jfloat mmx = nx * scale, mmy = ny * scale;
// if (isCW(omx, omy, mx, my) != isCW(mmx, mmy, mx, my)) then we've
// computed the wrong intersection so we get the other one.
// The test above is equivalent to if (rev).
if (rev) {
mmx = -mmx;
mmy = -mmy;
}
drawBezApproxForArc(pStroker, cx, cy, omx, omy, mmx, mmy, rev);
drawBezApproxForArc(pStroker, cx, cy, mmx, mmy, mx, my, rev);
break;
}
}
}
// the input arc defined by omx,omy and mx,my must span <= 90 degrees.
static void drawBezApproxForArc(PathConsumer *pStroker,
const jfloat cx, const jfloat cy,
const jfloat omx, const jfloat omy,
const jfloat mx, const jfloat my,
jboolean rev)
{
jfloat cosext2 = (omx * mx + omy * my) / (2 * this.lineWidth2 * this.lineWidth2);
// cv is the length of P1-P0 and P2-P3 divided by the radius of the arc
// (so, cv assumes the arc has radius 1). P0, P1, P2, P3 are the points that
// define the bezier curve we're computing.
// It is computed using the constraints that P1-P0 and P3-P2 are parallel
// to the arc tangents at the endpoints, and that |P1-P0|=|P3-P2|.
jfloat cv = (jfloat) ((4.0 / 3.0) * sqrt(0.5-cosext2) /
(1.0 + sqrt(cosext2+0.5)));
jfloat x1, y1, x2, y2, x3, y3, x4, y4;
// if clockwise, we need to negate cv.
if (rev) { // rev is equivalent to isCW(omx, omy, mx, my)
cv = -cv;
}
x1 = cx + omx;
y1 = cy + omy;
x2 = x1 - cv * omy;
y2 = y1 + cv * omx;
x4 = cx + mx;
y4 = cy + my;
x3 = x4 + cv * my;
y3 = y4 - cv * mx;
emitCurveTo(pStroker, x1, y1, x2, y2, x3, y3, x4, y4, rev);
}
static void drawRoundCap(PathConsumer *pStroker, jfloat cx, jfloat cy, jfloat mx, jfloat my) {
const jfloat C = 0.5522847498307933f;
// the first and second arguments of the following two calls
// are really will be ignored by emitCurveTo (because of the false),
// but we put them in anyway, as opposed to just giving it 4 zeroes,
// because it's just 4 additions and it's not good to rely on this
// sort of assumption (right now it's true, but that may change).
emitCurveTo(pStroker,
cx+mx, cy+my,
cx+mx-C*my, cy+my+C*mx,
cx-my+C*mx, cy+mx+C*my,
cx-my, cy+mx,
JNI_FALSE);
emitCurveTo(pStroker,
cx-my, cy+mx,
cx-my-C*mx, cy+mx-C*my,
cx-mx-C*my, cy-my+C*mx,
cx-mx, cy-my,
JNI_FALSE);
}
// Return the intersection point of the lines (x0, y0) -> (x1, y1)
// and (x0p, y0p) -> (x1p, y1p) in m[0] and m[1]
static void computeMiter(const jfloat x0, const jfloat y0,
const jfloat x1, const jfloat y1,
const jfloat x0p, const jfloat y0p,
const jfloat x1p, const jfloat y1p,
jfloat m[], jint off)
{
jfloat x10 = x1 - x0;
jfloat y10 = y1 - y0;
jfloat x10p = x1p - x0p;
jfloat y10p = y1p - y0p;
// if this is 0, the lines are parallel. If they go in the
// same direction, there is no intersection so m[off] and
// m[off+1] will contain infinity, so no miter will be drawn.
// If they go in the same direction that means that the start of the
// current segment and the end of the previous segment have the same
// tangent, in which case this method won't even be involved in
// miter drawing because it won't be called by drawMiter (because
// (mx == omx && my == omy) will be true, and drawMiter will return
// immediately).
jfloat den = x10*y10p - x10p*y10;
jfloat t = x10p*(y0-y0p) - y10p*(x0-x0p);
t /= den;
m[off++] = x0 + t*x10;
m[off] = y0 + t*y10;
}
// Return the intersection point of the lines (x0, y0) -> (x1, y1)
// and (x0p, y0p) -> (x1p, y1p) in m[0] and m[1]
static void safecomputeMiter(const jfloat x0, const jfloat y0,
const jfloat x1, const jfloat y1,
const jfloat x0p, const jfloat y0p,
const jfloat x1p, const jfloat y1p,
jfloat m[], jint off)
{
jfloat x10 = x1 - x0;
jfloat y10 = y1 - y0;
jfloat x10p = x1p - x0p;
jfloat y10p = y1p - y0p;
// if this is 0, the lines are parallel. If they go in the
// same direction, there is no intersection so m[off] and
// m[off+1] will contain infinity, so no miter will be drawn.
// If they go in the same direction that means that the start of the
// current segment and the end of the previous segment have the same
// tangent, in which case this method won't even be involved in
// miter drawing because it won't be called by drawMiter (because
// (mx == omx && my == omy) will be true, and drawMiter will return
// immediately).
jfloat den = x10*y10p - x10p*y10;
jfloat t;
if (den == 0) {
m[off++] = (x0 + x0p) / 2.0f;
m[off] = (y0 + y0p) / 2.0f;
return;
}
t = x10p*(y0-y0p) - y10p*(x0-x0p);
t /= den;
m[off++] = x0 + t*x10;
m[off] = y0 + t*y10;
}
static void drawMiter(PathConsumer *pStroker,
const jfloat pdx, const jfloat pdy,
const jfloat x0, const jfloat y0,
const jfloat dx, const jfloat dy,
jfloat omx, jfloat omy, jfloat mx, jfloat my,
jboolean rev)
{
jfloat lenSq;
if ((mx == omx && my == omy) ||
(pdx == 0 && pdy == 0) ||
(dx == 0 && dy == 0)) {
return;
}
if (rev) {
omx = -omx;
omy = -omy;
mx = -mx;
my = -my;
}
computeMiter((x0 - pdx) + omx, (y0 - pdy) + omy, x0 + omx, y0 + omy,
(dx + x0) + mx, (dy + y0) + my, x0 + mx, y0 + my,
this.miter, 0);
lenSq = (this.miter[0]-x0)*(this.miter[0]-x0) + (this.miter[1]-y0)*(this.miter[1]-y0);
if (lenSq < this.miterLimitSq) {
emitLineTo(pStroker, this.miter[0], this.miter[1], rev);
}
}
static void Stroker_moveTo(PathConsumer *pStroker, jfloat x0, jfloat y0) {
if (this.prev == DRAWING_OP_TO) {
finish(pStroker);
}
this.sx0 = this.cx0 = x0;
this.sy0 = this.cy0 = y0;
this.cdx = this.sdx = 1;
this.cdy = this.sdy = 0;
this.prev = MOVE_TO;
}
static void Stroker_lineTo(PathConsumer *pStroker, jfloat x1, jfloat y1) {
jfloat dx = x1 - this.cx0;
jfloat dy = y1 - this.cy0;
jfloat mx, my;
if (dx == 0.0f && dy == 0.0f) {
dx = 1;
}
computeOffset(dx, dy, this.lineWidth2, this.offset[0]);
mx = this.offset[0][0];
my = this.offset[0][1];
drawJoin(pStroker,
this.cdx, this.cdy, this.cx0, this.cy0,
dx, dy, this.cmx, this.cmy, mx, my);
emitLineTo(pStroker, this.cx0 + mx, this.cy0 + my, JNI_FALSE);
emitLineTo(pStroker, x1 + mx, y1 + my, JNI_FALSE);
emitLineTo(pStroker, this.cx0 - mx, this.cy0 - my, JNI_TRUE);
emitLineTo(pStroker, x1 - mx, y1 - my, JNI_TRUE);
this.cmx = mx;
this.cmy = my;
this.cdx = dx;
this.cdy = dy;
this.cx0 = x1;
this.cy0 = y1;
this.prev = DRAWING_OP_TO;
}
static void Stroker_closePath(PathConsumer *pStroker) {
if (this.prev != DRAWING_OP_TO) {
if (this.prev == CLOSE) {
return;
}
emitMoveTo(pStroker, this.cx0, this.cy0 - this.lineWidth2);
this.cmx = this.smx = 0;
this.cmy = this.smy = -this.lineWidth2;
this.cdx = this.sdx = 1;
this.cdy = this.sdy = 0;
finish(pStroker);
return;
}
if (this.cx0 != this.sx0 || this.cy0 != this.sy0) {
Stroker_lineTo(pStroker, this.sx0, this.sy0);
}
drawJoin(pStroker,
this.cdx, this.cdy, this.cx0, this.cy0,
this.sdx, this.sdy, this.cmx, this.cmy,
this.smx, this.smy);
emitLineTo(pStroker, this.sx0 + this.smx, this.sy0 + this.smy, JNI_FALSE);
emitMoveTo(pStroker, this.sx0 - this.smx, this.sy0 - this.smy);
emitReverse(pStroker);
this.prev = CLOSE;
emitClose(pStroker);
}
static void emitReverse(PathConsumer *pStroker) {
while (!PolyStack_isEmpty(&this.reverse)) {
PolyStack_pop(&this.reverse, this.out);
}
}
static void Stroker_pathDone(PathConsumer *pStroker) {
if (this.prev == DRAWING_OP_TO) {
finish(pStroker);
}
this.out->pathDone(this.out);
// this shouldn't matter since this object won't be used
// after the call to this method.
this.prev = CLOSE;
}
static void finish(PathConsumer *pStroker) {
if (this.capStyle == CAP_ROUND) {
drawRoundCap(pStroker, this.cx0, this.cy0, this.cmx, this.cmy);
} else if (this.capStyle == CAP_SQUARE) {
emitLineTo(pStroker, this.cx0 - this.cmy + this.cmx, this.cy0 + this.cmx + this.cmy, JNI_FALSE);
emitLineTo(pStroker, this.cx0 - this.cmy - this.cmx, this.cy0 + this.cmx - this.cmy, JNI_FALSE);
}
emitReverse(pStroker);
if (this.capStyle == CAP_ROUND) {
drawRoundCap(pStroker, this.sx0, this.sy0, -this.smx, -this.smy);
} else if (this.capStyle == CAP_SQUARE) {
emitLineTo(pStroker, this.sx0 + this.smy - this.smx, this.sy0 - this.smx - this.smy, JNI_FALSE);
emitLineTo(pStroker, this.sx0 + this.smy + this.smx, this.sy0 - this.smx + this.smy, JNI_FALSE);
}
emitClose(pStroker);
}
static void emitMoveTo(PathConsumer *pStroker, const jfloat x0, const jfloat y0) {
this.out->moveTo(this.out, x0, y0);
}
static void emitLineTo(PathConsumer *pStroker, const jfloat x1, const jfloat y1,
const jboolean rev)
{
if (rev) {
PolyStack_pushLine(&this.reverse, x1, y1);
} else {
this.out->lineTo(this.out, x1, y1);
}
}
static void emitQuadTo(PathConsumer *pStroker,
const jfloat x0, const jfloat y0,
const jfloat x1, const jfloat y1,
const jfloat x2, const jfloat y2, const jboolean rev)
{
if (rev) {
PolyStack_pushQuad(&this.reverse, x0, y0, x1, y1);
} else {
this.out->quadTo(this.out, x1, y1, x2, y2);
}
}
static void emitCurveTo(PathConsumer *pStroker,
const jfloat x0, const jfloat y0,
const jfloat x1, const jfloat y1,
const jfloat x2, const jfloat y2,
const jfloat x3, const jfloat y3, const jboolean rev)
{
if (rev) {
PolyStack_pushCubic(&this.reverse, x0, y0, x1, y1, x2, y2);
} else {
this.out->curveTo(this.out, x1, y1, x2, y2, x3, y3);
}
}
static void emitClose(PathConsumer *pStroker) {
this.out->closePath(this.out);
}
static void drawJoin(PathConsumer *pStroker,
jfloat pdx, jfloat pdy,
jfloat x0, jfloat y0,
jfloat dx, jfloat dy,
jfloat omx, jfloat omy,
jfloat mx, jfloat my)
{
if (this.prev != DRAWING_OP_TO) {
emitMoveTo(pStroker, x0 + mx, y0 + my);
this.sdx = dx;
this.sdy = dy;
this.smx = mx;
this.smy = my;
} else {
jboolean cw = isCW(pdx, pdy, dx, dy);
if (this.joinStyle == JOIN_MITER) {
drawMiter(pStroker, pdx, pdy, x0, y0, dx, dy, omx, omy, mx, my, cw);
} else if (this.joinStyle == JOIN_ROUND) {
drawRoundJoin(pStroker,
x0, y0,
omx, omy,
mx, my, cw,
ROUND_JOIN_THRESHOLD);
}
emitLineTo(pStroker, x0, y0, !cw);
}
this.prev = DRAWING_OP_TO;
}
static jboolean withinULP(const jfloat x1, const jfloat y1,
const jfloat x2, const jfloat y2,
const int maxUlps)
{
// assert maxUlps is much smaller than 0x7fffffff;
// compare taxicab distance. ERR will always be small, so using
// true distance won't give much benefit
return (Helpers_withinULP(x1, x2, maxUlps) &&
Helpers_withinULP(y1, y2, maxUlps));
}
static void getLineOffsets(PathConsumer *pStroker,
jfloat x1, jfloat y1,
jfloat x2, jfloat y2,
jfloat left[], jfloat right[]) {
computeOffset(x2 - x1, y2 - y1, this.lineWidth2, this.offset[0]);
left[0] = x1 + this.offset[0][0];
left[1] = y1 + this.offset[0][1];
left[2] = x2 + this.offset[0][0];
left[3] = y2 + this.offset[0][1];
right[0] = x1 - this.offset[0][0];
right[1] = y1 - this.offset[0][1];
right[2] = x2 - this.offset[0][0];
right[3] = y2 - this.offset[0][1];
}
static jint computeOffsetCubic(PathConsumer *pStroker,
jfloat pts[], const jint off,
jfloat leftOff[], jfloat rightOff[])
{
jfloat dotsq, l1sq, l4sq;
jfloat x, y, dxm, dym;
// if p1=p2 or p3=p4 it means that the derivative at the endpoint
// vanishes, which creates problems with computeOffset. Usually
// this happens when this stroker object is trying to winden
// a curve with a cusp. What happens is that curveTo splits
// the input curve at the cusp, and passes it to this function.
// because of inaccuracies in the splitting, we consider points
// equal if they're very close to each other.
const jfloat x1 = pts[off + 0], y1 = pts[off + 1];
const jfloat x2 = pts[off + 2], y2 = pts[off + 3];
const jfloat x3 = pts[off + 4], y3 = pts[off + 5];
const jfloat x4 = pts[off + 6], y4 = pts[off + 7];
jfloat dx4 = x4 - x3;
jfloat dy4 = y4 - y3;
jfloat dx1 = x2 - x1;
jfloat dy1 = y2 - y1;
// if p1 == p2 && p3 == p4: draw line from p1->p4, unless p1 == p4,
// in which case ignore if p1 == p2
const jboolean p1eqp2 = withinULP(x1,y1,x2,y2, 6);
const jboolean p3eqp4 = withinULP(x3,y3,x4,y4, 6);
if (p1eqp2 && p3eqp4) {
getLineOffsets(pStroker, x1, y1, x4, y4, leftOff, rightOff);
return 4;
} else if (p1eqp2) {
dx1 = x3 - x1;
dy1 = y3 - y1;
} else if (p3eqp4) {
dx4 = x4 - x2;
dy4 = y4 - y2;
}
// if p2-p1 and p4-p3 are parallel, that must mean this curve is a line
dotsq = (dx1 * dx4 + dy1 * dy4);
dotsq = dotsq * dotsq;
l1sq = dx1 * dx1 + dy1 * dy1;
l4sq = dx4 * dx4 + dy4 * dy4;
if (Helpers_withinULP(dotsq, l1sq * l4sq, 4)) {
getLineOffsets(pStroker, x1, y1, x4, y4, leftOff, rightOff);
return 4;
}
// What we're trying to do in this function is to approximate an ideal
// offset curve (call it I) of the input curve B using a bezier curve Bp.
// The constraints I use to get the equations are:
//
// 1. The computed curve Bp should go through I(0) and I(1). These are
// x1p, y1p, x4p, y4p, which are p1p and p4p. We still need to find
// 4 variables: the x and y components of p2p and p3p (i.e. x2p, y2p, x3p, y3p).
//
// 2. Bp should have slope equal in absolute value to I at the endpoints. So,
// (by the way, the operator || in the comments below means "aligned with".
// It is defined on vectors, so when we say I'(0) || Bp'(0) we mean that
// vectors I'(0) and Bp'(0) are aligned, which is the same as saying
// that the tangent lines of I and Bp at 0 are parallel. Mathematically
// this means (I'(t) || Bp'(t)) <==> (I'(t) = c * Bp'(t)) where c is some
// nonzero constant.)
// I'(0) || Bp'(0) and I'(1) || Bp'(1). Obviously, I'(0) || B'(0) and
// I'(1) || B'(1); therefore, Bp'(0) || B'(0) and Bp'(1) || B'(1).
// We know that Bp'(0) || (p2p-p1p) and Bp'(1) || (p4p-p3p) and the same
// is true for any bezier curve; therefore, we get the equations
// (1) p2p = c1 * (p2-p1) + p1p
// (2) p3p = c2 * (p4-p3) + p4p
// We know p1p, p4p, p2, p1, p3, and p4; therefore, this reduces the number
// of unknowns from 4 to 2 (i.e. just c1 and c2).
// To eliminate these 2 unknowns we use the following constraint:
//
// 3. Bp(0.5) == I(0.5). Bp(0.5)=(x,y) and I(0.5)=(xi,yi), and I should note
// that I(0.5) is *the only* reason for computing dxm,dym. This gives us
// (3) Bp(0.5) = (p1p + 3 * (p2p + p3p) + p4p)/8, which is equivalent to
// (4) p2p + p3p = (Bp(0.5)*8 - p1p - p4p) / 3
// We can substitute (1) and (2) from above into (4) and we get:
// (5) c1*(p2-p1) + c2*(p4-p3) = (Bp(0.5)*8 - p1p - p4p)/3 - p1p - p4p
// which is equivalent to
// (6) c1*(p2-p1) + c2*(p4-p3) = (4/3) * (Bp(0.5) * 2 - p1p - p4p)
//
// The right side of this is a 2D vector, and we know I(0.5), which gives us
// Bp(0.5), which gives us the value of the right side.
// The left side is just a matrix vector multiplication in disguise. It is
//
// [x2-x1, x4-x3][c1]
// [y2-y1, y4-y3][c2]
// which, is equal to
// [dx1, dx4][c1]
// [dy1, dy4][c2]
// At this point we are left with a simple linear system and we solve it by
// getting the inverse of the matrix above. Then we use [c1,c2] to compute
// p2p and p3p.
x = 0.125f * (x1 + 3 * (x2 + x3) + x4);
y = 0.125f * (y1 + 3 * (y2 + y3) + y4);
// (dxm,dym) is some tangent of B at t=0.5. This means it's equal to
// c*B'(0.5) for some constant c.
dxm = x3 + x4 - x1 - x2;
dym = y3 + y4 - y1 - y2;
// this computes the offsets at t=0, 0.5, 1, using the property that
// for any bezier curve the vectors p2-p1 and p4-p3 are parallel to
// the (dx/dt, dy/dt) vectors at the endpoints.
computeOffset(dx1, dy1, this.lineWidth2, this.offset[0]);
computeOffset(dxm, dym, this.lineWidth2, this.offset[1]);
computeOffset(dx4, dy4, this.lineWidth2, this.offset[2]);
{
jfloat x1p = x1 + this.offset[0][0]; // start
jfloat y1p = y1 + this.offset[0][1]; // point
jfloat xi = x + this.offset[1][0]; // interpolation
jfloat yi = y + this.offset[1][1]; // point
jfloat x4p = x4 + this.offset[2][0]; // end
jfloat y4p = y4 + this.offset[2][1]; // point
jfloat invdet43 = 4.0f / (3.0f * (dx1 * dy4 - dy1 * dx4));
jfloat two_pi_m_p1_m_p4x = 2*xi - x1p - x4p;
jfloat two_pi_m_p1_m_p4y = 2*yi - y1p - y4p;
jfloat c1 = invdet43 * (dy4 * two_pi_m_p1_m_p4x - dx4 * two_pi_m_p1_m_p4y);
jfloat c2 = invdet43 * (dx1 * two_pi_m_p1_m_p4y - dy1 * two_pi_m_p1_m_p4x);
jfloat x2p, y2p, x3p, y3p;
x2p = x1p + c1*dx1;
y2p = y1p + c1*dy1;
x3p = x4p + c2*dx4;
y3p = y4p + c2*dy4;
leftOff[0] = x1p; leftOff[1] = y1p;
leftOff[2] = x2p; leftOff[3] = y2p;
leftOff[4] = x3p; leftOff[5] = y3p;
leftOff[6] = x4p; leftOff[7] = y4p;
x1p = x1 - this.offset[0][0]; y1p = y1 - this.offset[0][1];
xi = xi - 2 * this.offset[1][0]; yi = yi - 2 * this.offset[1][1];
x4p = x4 - this.offset[2][0]; y4p = y4 - this.offset[2][1];
two_pi_m_p1_m_p4x = 2*xi - x1p - x4p;
two_pi_m_p1_m_p4y = 2*yi - y1p - y4p;
c1 = invdet43 * (dy4 * two_pi_m_p1_m_p4x - dx4 * two_pi_m_p1_m_p4y);
c2 = invdet43 * (dx1 * two_pi_m_p1_m_p4y - dy1 * two_pi_m_p1_m_p4x);
x2p = x1p + c1*dx1;
y2p = y1p + c1*dy1;
x3p = x4p + c2*dx4;
y3p = y4p + c2*dy4;
rightOff[0] = x1p; rightOff[1] = y1p;
rightOff[2] = x2p; rightOff[3] = y2p;
rightOff[4] = x3p; rightOff[5] = y3p;
rightOff[6] = x4p; rightOff[7] = y4p;
}
return 8;
}
// compute offset curves using bezier spline through t=0.5 (i.e.
// ComputedCurve(0.5) == IdealParallelCurve(0.5))
// return the kind of curve in the right and left arrays.
static jint computeOffsetQuad(PathConsumer *pStroker,
jfloat pts[], const jint off,
jfloat leftOff[], jfloat rightOff[])
{
const jfloat x1 = pts[off + 0], y1 = pts[off + 1];
const jfloat x2 = pts[off + 2], y2 = pts[off + 3];
const jfloat x3 = pts[off + 4], y3 = pts[off + 5];
jfloat dotsq, l1sq, l3sq;
jfloat dx3 = x3 - x2;
jfloat dy3 = y3 - y2;
jfloat dx1 = x2 - x1;
jfloat dy1 = y2 - y1;
// if p1=p2 or p3=p4 it means that the derivative at the endpoint
// vanishes, which creates problems with computeOffset. Usually
// this happens when this stroker object is trying to winden
// a curve with a cusp. What happens is that curveTo splits
// the input curve at the cusp, and passes it to this function.
// because of inaccuracies in the splitting, we consider points
// equal if they're very close to each other.
// if p1 == p2 && p3 == p4: draw line from p1->p4, unless p1 == p4,
// in which case ignore.
const jboolean p1eqp2 = withinULP(x1,y1,x2,y2, 6);
const jboolean p2eqp3 = withinULP(x2,y2,x3,y3, 6);
if (p1eqp2 || p2eqp3) {
getLineOffsets(pStroker, x1, y1, x3, y3, leftOff, rightOff);
return 4;
}
// if p2-p1 and p4-p3 are parallel, that must mean this curve is a line
dotsq = (dx1 * dx3 + dy1 * dy3);
dotsq = dotsq * dotsq;
l1sq = dx1 * dx1 + dy1 * dy1;
l3sq = dx3 * dx3 + dy3 * dy3;
if (Helpers_withinULP(dotsq, l1sq * l3sq, 4)) {
getLineOffsets(pStroker, x1, y1, x3, y3, leftOff, rightOff);
return 4;
}
// this computes the offsets at t=0, 0.5, 1, using the property that
// for any bezier curve the vectors p2-p1 and p4-p3 are parallel to
// the (dx/dt, dy/dt) vectors at the endpoints.
computeOffset(dx1, dy1, this.lineWidth2, this.offset[0]);
computeOffset(dx3, dy3, this.lineWidth2, this.offset[1]);
{
jfloat x1p = x1 + this.offset[0][0]; // start
jfloat y1p = y1 + this.offset[0][1]; // point
jfloat x3p = x3 + this.offset[1][0]; // end
jfloat y3p = y3 + this.offset[1][1]; // point
safecomputeMiter(x1p, y1p, x1p+dx1, y1p+dy1, x3p, y3p, x3p-dx3, y3p-dy3, leftOff, 2);
leftOff[0] = x1p; leftOff[1] = y1p;
leftOff[4] = x3p; leftOff[5] = y3p;
x1p = x1 - this.offset[0][0]; y1p = y1 - this.offset[0][1];
x3p = x3 - this.offset[1][0]; y3p = y3 - this.offset[1][1];
safecomputeMiter(x1p, y1p, x1p+dx1, y1p+dy1, x3p, y3p, x3p-dx3, y3p-dy3, rightOff, 2);
rightOff[0] = x1p; rightOff[1] = y1p;
rightOff[4] = x3p; rightOff[5] = y3p;
}
return 6;
}
// This is where the curve to be processed is put. We give it
// enough room to store 2 curves: one for the current subdivision, the
// other for the rest of the curve.
#define MAX_N_CURVES 11
static jfloat middle[MAX_N_CURVES*8];
static jfloat lp[8];
static jfloat rp[8];
static jfloat subdivTs[MAX_N_CURVES - 1];
// The following variation of somethingTo() caused problems when this was
// Java code as indicated by the following comment. Now that this code has
// been converted into C, we should look at investigating the potential
// performance benefits of using this version instead of the "safer" version
// that survived in the Java sources and is currently being used below.
// If this class is compiled with ecj, then Hotspot crashes when OSR
// compiling this function. See bugs 7004570 and 6675699
// NOTE: until those are fixed, we should work around that by
// manually inlining this into curveTo and quadTo.
/******************************* WORKAROUND **********************************
private void somethingTo(final int type) {
// need these so we can update the state at the end of this method
final float xf = middle[type-2], yf = middle[type-1];
float dxs = middle[2] - middle[0];
float dys = middle[3] - middle[1];
float dxf = middle[type - 2] - middle[type - 4];
float dyf = middle[type - 1] - middle[type - 3];
switch(type) {
case 6:
if ((dxs == 0f && dys == 0f) ||
(dxf == 0f && dyf == 0f)) {
dxs = dxf = middle[4] - middle[0];
dys = dyf = middle[5] - middle[1];
}
break;
case 8:
boolean p1eqp2 = (dxs == 0f && dys == 0f);
boolean p3eqp4 = (dxf == 0f && dyf == 0f);
if (p1eqp2) {
dxs = middle[4] - middle[0];
dys = middle[5] - middle[1];
if (dxs == 0f && dys == 0f) {
dxs = middle[6] - middle[0];
dys = middle[7] - middle[1];
}
}
if (p3eqp4) {
dxf = middle[6] - middle[2];
dyf = middle[7] - middle[3];
if (dxf == 0f && dyf == 0f) {
dxf = middle[6] - middle[0];
dyf = middle[7] - middle[1];
}
}
}
if (dxs == 0f && dys == 0f) {
// this happens iff the "curve" is just a point
lineTo(middle[0], middle[1]);
return;
}
// if these vectors are too small, normalize them, to avoid future
// precision problems.
if (Math.abs(dxs) < 0.1f && Math.abs(dys) < 0.1f) {
float len = (float)Math.sqrt(dxs*dxs + dys*dys);
dxs /= len;
dys /= len;
}
if (Math.abs(dxf) < 0.1f && Math.abs(dyf) < 0.1f) {
float len = (float)Math.sqrt(dxf*dxf + dyf*dyf);
dxf /= len;
dyf /= len;
}
computeOffset(dxs, dys, lineWidth2, offset[0]);
final float mx = offset[0][0];
final float my = offset[0][1];
drawJoin(pStroker, cdx, cdy, cx0, cy0, dxs, dys, cmx, cmy, mx, my);
int nSplits = findSubdivPoints(pStroker, middle, subdivTs, type, lineWidth2);
int kind = 0;
Iterator it = Curve.breakPtsAtTs(middle, type, subdivTs, nSplits);
while(it.hasNext()) {
int curCurveOff = it.next();
kind = 0;
switch (type) {
case 8:
kind = computeOffsetCubic(middle, curCurveOff, lp, rp);
break;
case 6:
kind = computeOffsetQuad(middle, curCurveOff, lp, rp);
break;
}
if (kind != 0) {
emitLineTo(pStroker, lp[0], lp[1], JNI_FALSE);
switch(kind) {
case 8:
emitCurveTo(pStroker, lp[0], lp[1], lp[2], lp[3], lp[4], lp[5], lp[6], lp[7], false);
emitCurveTo(pStroker, rp[0], rp[1], rp[2], rp[3], rp[4], rp[5], rp[6], rp[7], true);
break;
case 6:
emitQuadTo(pStroker, lp[0], lp[1], lp[2], lp[3], lp[4], lp[5], false);
emitQuadTo(pStroker, rp[0], rp[1], rp[2], rp[3], rp[4], rp[5], true);
break;
case 4:
emitLineTo(pStroker, lp[2], lp[3], JNI_FALSE);
emitLineTo(pStroker, rp[0], rp[1], JNI_TRUE);
break;
}
emitLineTo(pStroker, rp[kind - 2], rp[kind - 1], true);
}
}
this.cmx = (lp[kind - 2] - rp[kind - 2]) / 2;
this.cmy = (lp[kind - 1] - rp[kind - 1]) / 2;
this.cdx = dxf;
this.cdy = dyf;
this.cx0 = xf;
this.cy0 = yf;
this.prev = DRAWING_OP_TO;
}
****************************** END WORKAROUND *******************************/
// finds values of t where the curve in pts should be subdivided in order
// to get good offset curves a distance of w away from the middle curve.
// Stores the points in ts, and returns how many of them there were.
static jint findSubdivPoints(PathConsumer *pStroker,
jfloat pts[], jfloat ts[],
const jint type, const jfloat w)
{
jint ret = 0;
const jfloat x12 = pts[2] - pts[0];
const jfloat y12 = pts[3] - pts[1];
// if the curve is already parallel to either axis we gain nothing
// from rotating it.
if (y12 != 0.0f && x12 != 0.0f) {
// we rotate it so that the first vector in the control polygon is
// parallel to the x-axis. This will ensure that rotated quarter
// circles won't be subdivided.
const jfloat hypot = (jfloat) sqrt(x12 * x12 + y12 * y12);
const jfloat cos = x12 / hypot;
const jfloat sin = y12 / hypot;
const jfloat x1 = cos * pts[0] + sin * pts[1];
const jfloat y1 = cos * pts[1] - sin * pts[0];
const jfloat x2 = cos * pts[2] + sin * pts[3];
const jfloat y2 = cos * pts[3] - sin * pts[2];
const jfloat x3 = cos * pts[4] + sin * pts[5];
const jfloat y3 = cos * pts[5] - sin * pts[4];
switch(type) {
case 8:
{
const jfloat x4 = cos * pts[6] + sin * pts[7];
const jfloat y4 = cos * pts[7] - sin * pts[6];
Curve_setcubic(&this.c, x1, y1, x2, y2, x3, y3, x4, y4);
break;
}
case 6:
Curve_setquad(&this.c, x1, y1, x2, y2, x3, y3);
break;
}
} else {
Curve_set(&this.c, pts, type);
}
// we subdivide at values of t such that the remaining rotated
// curves are monotonic in x and y.
ret += Curve_dxRoots(&this.c, ts, ret);
ret += Curve_dyRoots(&this.c, ts, ret);
// subdivide at inflection points.
if (type == 8) {
// quadratic curves can't have inflection points
ret += Curve_infPoints(&this.c, ts, ret);
}
// now we must subdivide at points where one of the offset curves will have
// a cusp. This happens at ts where the radius of curvature is equal to w.
ret += Curve_rootsOfROCMinusW(&this.c, ts, ret, w, 0.0001f);
ret = Helpers_filterOutNotInAB(ts, 0, ret, 0.0001f, 0.9999f);
Helpers_isort(ts, 0, ret);
return ret;
}
static void Stroker_curveTo(PathConsumer *pStroker,
jfloat x1, jfloat y1,
jfloat x2, jfloat y2,
jfloat x3, jfloat y3)
{
jfloat xf, yf, dxs, dys, dxf, dyf;
jfloat mx, my;
jint nSplits;
jfloat prevT;
jint i, kind;
jboolean p1eqp2, p3eqp4;
middle[0] = this.cx0; middle[1] = this.cy0;
middle[2] = x1; middle[3] = y1;
middle[4] = x2; middle[5] = y2;
middle[6] = x3; middle[7] = y3;
// inlined version of somethingTo(8);
// See the NOTE on somethingTo
// need these so we can update the state at the end of this method
xf = middle[6], yf = middle[7];
dxs = middle[2] - middle[0];
dys = middle[3] - middle[1];
dxf = middle[6] - middle[4];
dyf = middle[7] - middle[5];
p1eqp2 = (dxs == 0.0f && dys == 0.0f);
p3eqp4 = (dxf == 0.0f && dyf == 0.0f);
if (p1eqp2) {
dxs = middle[4] - middle[0];
dys = middle[5] - middle[1];
if (dxs == 0.0f && dys == 0.0f) {
dxs = middle[6] - middle[0];
dys = middle[7] - middle[1];
}
}
if (p3eqp4) {
dxf = middle[6] - middle[2];
dyf = middle[7] - middle[3];
if (dxf == 0.0f && dyf == 0.0f) {
dxf = middle[6] - middle[0];
dyf = middle[7] - middle[1];
}
}
if (dxs == 0.0f && dys == 0.0f) {
// this happens iff the "curve" is just a point
Stroker_lineTo(pStroker, middle[0], middle[1]);
return;
}
// if these vectors are too small, normalize them, to avoid future
// precision problems.
if (fabs(dxs) < 0.1f && fabs(dys) < 0.1f) {
jfloat len = (jfloat) sqrt(dxs*dxs + dys*dys);
dxs /= len;
dys /= len;
}
if (fabs(dxf) < 0.1f && fabs(dyf) < 0.1f) {
jfloat len = (jfloat) sqrt(dxf*dxf + dyf*dyf);
dxf /= len;
dyf /= len;
}
computeOffset(dxs, dys, this.lineWidth2, this.offset[0]);
mx = this.offset[0][0];
my = this.offset[0][1];
drawJoin(pStroker,
this.cdx, this.cdy, this.cx0, this.cy0,
dxs, dys, this.cmx, this.cmy,
mx, my);
nSplits = findSubdivPoints(pStroker, middle, subdivTs, 8, this.lineWidth2);
prevT = 0.0f;
for (i = 0; i < nSplits; i++) {
jfloat t = subdivTs[i];
Helpers_subdivideCubicAt((t - prevT) / (1 - prevT),
middle, i*6,
middle, i*6,
middle, i*6+6);
prevT = t;
}
kind = 0;
for (i = 0; i <= nSplits; i++) {
kind = computeOffsetCubic(pStroker, middle, i*6, lp, rp);
if (kind != 0) {
emitLineTo(pStroker, lp[0], lp[1], JNI_FALSE);
switch(kind) {
case 8:
emitCurveTo(pStroker, lp[0], lp[1], lp[2], lp[3], lp[4], lp[5], lp[6], lp[7], JNI_FALSE);
emitCurveTo(pStroker, rp[0], rp[1], rp[2], rp[3], rp[4], rp[5], rp[6], rp[7], JNI_TRUE);
break;
case 4:
emitLineTo(pStroker, lp[2], lp[3], JNI_FALSE);
emitLineTo(pStroker, rp[0], rp[1], JNI_TRUE);
break;
}
emitLineTo(pStroker, rp[kind - 2], rp[kind - 1], JNI_TRUE);
}
}
this.cmx = (lp[kind - 2] - rp[kind - 2]) / 2;
this.cmy = (lp[kind - 1] - rp[kind - 1]) / 2;
this.cdx = dxf;
this.cdy = dyf;
this.cx0 = xf;
this.cy0 = yf;
this.prev = DRAWING_OP_TO;
}
static void Stroker_quadTo(PathConsumer *pStroker,
jfloat x1, jfloat y1,
jfloat x2, jfloat y2)
{
jfloat xf, yf, dxs, dys, dxf, dyf;
jfloat mx, my;
jint nSplits, i, kind;
jfloat prevt;
middle[0] = this.cx0; middle[1] = this.cy0;
middle[2] = x1; middle[3] = y1;
middle[4] = x2; middle[5] = y2;
// inlined version of somethingTo(8);
// See the NOTE on somethingTo
// need these so we can update the state at the end of this method
xf = middle[4], yf = middle[5];
dxs = middle[2] - middle[0];
dys = middle[3] - middle[1];
dxf = middle[4] - middle[2];
dyf = middle[5] - middle[3];
if ((dxs == 0.0f && dys == 0.0f) || (dxf == 0.0f && dyf == 0.0f)) {
dxs = dxf = middle[4] - middle[0];
dys = dyf = middle[5] - middle[1];
}
if (dxs == 0.0f && dys == 0.0f) {
// this happens iff the "curve" is just a point
Stroker_lineTo(pStroker, middle[0], middle[1]);
return;
}
// if these vectors are too small, normalize them, to avoid future
// precision problems.
if (fabs(dxs) < 0.1f && fabs(dys) < 0.1f) {
jfloat len = (jfloat) sqrt(dxs*dxs + dys*dys);
dxs /= len;
dys /= len;
}
if (fabs(dxf) < 0.1f && fabs(dyf) < 0.1f) {
jfloat len = (jfloat) sqrt(dxf*dxf + dyf*dyf);
dxf /= len;
dyf /= len;
}
computeOffset(dxs, dys, this.lineWidth2, this.offset[0]);
mx = this.offset[0][0];
my = this.offset[0][1];
drawJoin(pStroker,
this.cdx, this.cdy, this.cx0, this.cy0,
dxs, dys, this.cmx, this.cmy,
mx, my);
nSplits = findSubdivPoints(pStroker, middle, subdivTs, 6, this.lineWidth2);
prevt = 0.0f;
for (i = 0; i < nSplits; i++) {
jfloat t = subdivTs[i];
Helpers_subdivideQuadAt((t - prevt) / (1 - prevt),
middle, i*4,
middle, i*4,
middle, i*4+4);
prevt = t;
}
kind = 0;
for (i = 0; i <= nSplits; i++) {
kind = computeOffsetQuad(pStroker, middle, i*4, lp, rp);
if (kind != 0) {
emitLineTo(pStroker, lp[0], lp[1], JNI_FALSE);
switch(kind) {
case 6:
emitQuadTo(pStroker, lp[0], lp[1], lp[2], lp[3], lp[4], lp[5], JNI_FALSE);
emitQuadTo(pStroker, rp[0], rp[1], rp[2], rp[3], rp[4], rp[5], JNI_TRUE);
break;
case 4:
emitLineTo(pStroker, lp[2], lp[3], JNI_FALSE);
emitLineTo(pStroker, rp[0], rp[1], JNI_TRUE);
break;
}
emitLineTo(pStroker, rp[kind - 2], rp[kind - 1], JNI_TRUE);
}
}
this.cmx = (lp[kind - 2] - rp[kind - 2]) / 2;
this.cmy = (lp[kind - 1] - rp[kind - 1]) / 2;
this.cdx = dxf;
this.cdy = dyf;
this.cx0 = xf;
this.cy0 = yf;
this.prev = DRAWING_OP_TO;
}
// a stack of polynomial curves where each curve shares endpoints with
// adjacent ones.
/*
private static const class PolyStack {
jfloat[] curves;
int end;
int[] curveTypes;
int numCurves;
*/
#define INIT_SIZE 50
#undef this
#define this (*((PolyStack *)pStack))
void PolyStack_init(PolyStack *pStack) {
this.curves = new_float(8 * INIT_SIZE);
this.curvesSIZE = 8 * INIT_SIZE;
this.curveTypes = new_int(INIT_SIZE);
this.curveTypesSIZE = INIT_SIZE;
this.end = 0;
this.numCurves = 0;
}
void PolyStack_destroy(PolyStack *pStack) {
free(this.curves);
this.curves = NULL;
this.curvesSIZE = 0;
free(this.curveTypes);
this.curveTypes = NULL;
this.curveTypesSIZE = 0;
}
jboolean PolyStack_isEmpty(PolyStack *pStack) {
return this.numCurves == 0;
}
static void ensureSpace(PolyStack *pStack, jint n) {
if (this.end + n >= this.curvesSIZE) {
jint newSize = (this.end + n) * 2;
jfloat *newCurves = new_float(newSize);
System_arraycopy(this.curves, 0, newCurves, 0, this.end);
free(this.curves);
this.curves = newCurves;
this.curvesSIZE = newSize;
}
if (this.numCurves >= this.curveTypesSIZE) {
jint newSize = this.numCurves * 2;
jint *newTypes = new_int(newSize);
System_arraycopy(this.curveTypes, 0, newTypes, 0, this.numCurves);
free(this.curveTypes);
this.curveTypes = newTypes;
this.curveTypesSIZE = newSize;
}
}
void PolyStack_pushCubic(PolyStack *pStack,
jfloat x0, jfloat y0,
jfloat x1, jfloat y1,
jfloat x2, jfloat y2)
{
ensureSpace(pStack, 6);
this.curveTypes[this.numCurves++] = 8;
// assert(x0 == lastX && y0 == lastY)
// we reverse the coordinate order to make popping easier
this.curves[this.end++] = x2; this.curves[this.end++] = y2;
this.curves[this.end++] = x1; this.curves[this.end++] = y1;
this.curves[this.end++] = x0; this.curves[this.end++] = y0;
}
void PolyStack_pushQuad(PolyStack *pStack,
jfloat x0, jfloat y0,
jfloat x1, jfloat y1)
{
ensureSpace(pStack, 4);
this.curveTypes[this.numCurves++] = 6;
// assert(x0 == lastX && y0 == lastY)
this.curves[this.end++] = x1; this.curves[this.end++] = y1;
this.curves[this.end++] = x0; this.curves[this.end++] = y0;
}
void PolyStack_pushLine(PolyStack *pStack,
jfloat x, jfloat y)
{
ensureSpace(pStack, 2);
this.curveTypes[this.numCurves++] = 4;
// assert(x0 == lastX && y0 == lastY)
this.curves[this.end++] = x; this.curves[this.end++] = y;
}
//@SuppressWarnings("unused")
/*
jint PolyStack_pop(PolyStack *pStack, jfloat pts[]) {
jint ret = this.curveTypes[this.numCurves - 1];
this.numCurves--;
this.end -= (ret - 2);
System_arraycopy(curves, end, pts, 0, ret - 2);
return ret;
}
*/
void PolyStack_pop(PolyStack *pStack, PathConsumer *io) {
jint type;
this.numCurves--;
type = this.curveTypes[this.numCurves];
this.end -= (type - 2);
switch(type) {
case 8:
io->curveTo(io,
this.curves[this.end+0], this.curves[this.end+1],
this.curves[this.end+2], this.curves[this.end+3],
this.curves[this.end+4], this.curves[this.end+5]);
break;
case 6:
io->quadTo(io,
this.curves[this.end+0], this.curves[this.end+1],
this.curves[this.end+2], this.curves[this.end+3]);
break;
case 4:
io->lineTo(io, this.curves[this.end], this.curves[this.end+1]);
}
}
//@Override
/*
public String toString() {
String ret = "";
jint nc = numCurves;
jint last = this.end;
while (nc > 0) {
nc--;
jint type = curveTypes[numCurves];
last -= (type - 2);
switch(type) {
case 8:
ret += "cubic: ";
break;
case 6:
ret += "quad: ";
break;
case 4:
ret += "line: ";
break;
}
ret += Arrays.toString(Arrays.copyOfRange(curves, last, last+type-2)) + "\n";
}
return ret;
}
*/
