DDasher class takes a series of linear commands
+ * (moveTo, lineTo, close and
+ * end) and breaks them into smaller segments according to a
+ * dash pattern array and a starting dash phase.
+ *
+ * Issues: in J2Se, a zero length dash segment as drawn as a very
+ * short dash, whereas Pisces does not draw anything. The PostScript
+ * semantics are unclear.
+ *
+ */
+final class DDasher implements DPathConsumer2D, MarlinConst {
+
+ static final int REC_LIMIT = 4;
+ static final double ERR = 0.01d;
+ static final double MIN_T_INC = 1.0d / (1 << REC_LIMIT);
+
+ // More than 24 bits of mantissa means we can no longer accurately
+ // measure the number of times cycled through the dash array so we
+ // punt and override the phase to just be 0 past that point.
+ static final double MAX_CYCLES = 16000000.0d;
+
+ private DPathConsumer2D out;
+ private double[] dash;
+ private int dashLen;
+ private double startPhase;
+ private boolean startDashOn;
+ private int startIdx;
+
+ private boolean starting;
+ private boolean needsMoveTo;
+
+ private int idx;
+ private boolean dashOn;
+ private double phase;
+
+ private double sx, sy;
+ private double x0, y0;
+
+ // temporary storage for the current curve
+ private final double[] curCurvepts;
+
+ // per-thread renderer context
+ final DRendererContext rdrCtx;
+
+ // flag to recycle dash array copy
+ boolean recycleDashes;
+
+ // dashes ref (dirty)
+ final DoubleArrayCache.Reference dashes_ref;
+ // firstSegmentsBuffer ref (dirty)
+ final DoubleArrayCache.Reference firstSegmentsBuffer_ref;
+
+ /**
+ * Constructs a DDasher.
+ * @param rdrCtx per-thread renderer context
+ */
+ DDasher(final DRendererContext rdrCtx) {
+ this.rdrCtx = rdrCtx;
+
+ dashes_ref = rdrCtx.newDirtyDoubleArrayRef(INITIAL_ARRAY); // 1K
+
+ firstSegmentsBuffer_ref = rdrCtx.newDirtyDoubleArrayRef(INITIAL_ARRAY); // 1K
+ firstSegmentsBuffer = firstSegmentsBuffer_ref.initial;
+
+ // we need curCurvepts to be able to contain 2 curves because when
+ // dashing curves, we need to subdivide it
+ curCurvepts = new double[8 * 2];
+ }
+
+ /**
+ * Initialize the DDasher.
+ *
+ * @param out an output DPathConsumer2D.
+ * @param dash an array of doubles containing the dash pattern
+ * @param dashLen length of the given dash array
+ * @param phase a double containing the dash phase
+ * @param recycleDashes true to indicate to recycle the given dash array
+ * @return this instance
+ */
+ DDasher init(final DPathConsumer2D out, double[] dash, int dashLen,
+ double phase, boolean recycleDashes)
+ {
+ this.out = out;
+
+ // Normalize so 0 <= phase < dash[0]
+ int sidx = 0;
+ dashOn = true;
+ double sum = 0.0d;
+ for (double d : dash) {
+ sum += d;
+ }
+ double cycles = phase / sum;
+ if (phase < 0.0d) {
+ if (-cycles >= MAX_CYCLES) {
+ phase = 0.0d;
+ } else {
+ int fullcycles = FloatMath.floor_int(-cycles);
+ if ((fullcycles & dash.length & 1) != 0) {
+ dashOn = !dashOn;
+ }
+ phase += fullcycles * sum;
+ while (phase < 0.0d) {
+ if (--sidx < 0) {
+ sidx = dash.length - 1;
+ }
+ phase += dash[sidx];
+ dashOn = !dashOn;
+ }
+ }
+ } else if (phase > 0) {
+ if (cycles >= MAX_CYCLES) {
+ phase = 0.0d;
+ } else {
+ int fullcycles = FloatMath.floor_int(cycles);
+ if ((fullcycles & dash.length & 1) != 0) {
+ dashOn = !dashOn;
+ }
+ phase -= fullcycles * sum;
+ double d;
+ while (phase >= (d = dash[sidx])) {
+ phase -= d;
+ sidx = (sidx + 1) % dash.length;
+ dashOn = !dashOn;
+ }
+ }
+ }
+
+ this.dash = dash;
+ this.dashLen = dashLen;
+ this.startPhase = this.phase = phase;
+ this.startDashOn = dashOn;
+ this.startIdx = sidx;
+ this.starting = true;
+ needsMoveTo = false;
+ firstSegidx = 0;
+
+ this.recycleDashes = recycleDashes;
+
+ return this; // fluent API
+ }
+
+ /**
+ * Disposes this dasher:
+ * clean up before reusing this instance
+ */
+ void dispose() {
+ if (DO_CLEAN_DIRTY) {
+ // Force zero-fill dirty arrays:
+ Arrays.fill(curCurvepts, 0.0d);
+ }
+ // Return arrays:
+ if (recycleDashes) {
+ dash = dashes_ref.putArray(dash);
+ }
+ firstSegmentsBuffer = firstSegmentsBuffer_ref.putArray(firstSegmentsBuffer);
+ }
+
+ double[] copyDashArray(final float[] dashes) {
+ final int len = dashes.length;
+ final double[] newDashes;
+ if (len <= MarlinConst.INITIAL_ARRAY) {
+ newDashes = dashes_ref.initial;
+ } else {
+ if (DO_STATS) {
+ rdrCtx.stats.stat_array_dasher_dasher.add(len);
+ }
+ newDashes = dashes_ref.getArray(len);
+ }
+ for (int i = 0; i < len; i++) { newDashes[i] = dashes[i]; }
+ return newDashes;
+ }
+
+ @Override
+ public void moveTo(double x0, double y0) {
+ if (firstSegidx > 0) {
+ out.moveTo(sx, sy);
+ emitFirstSegments();
+ }
+ needsMoveTo = true;
+ this.idx = startIdx;
+ this.dashOn = this.startDashOn;
+ this.phase = this.startPhase;
+ this.sx = this.x0 = x0;
+ this.sy = this.y0 = y0;
+ this.starting = true;
+ }
+
+ private void emitSeg(double[] buf, int off, int type) {
+ switch (type) {
+ case 8:
+ out.curveTo(buf[off+0], buf[off+1],
+ buf[off+2], buf[off+3],
+ buf[off+4], buf[off+5]);
+ return;
+ case 6:
+ out.quadTo(buf[off+0], buf[off+1],
+ buf[off+2], buf[off+3]);
+ return;
+ case 4:
+ out.lineTo(buf[off], buf[off+1]);
+ return;
+ default:
+ }
+ }
+
+ private void emitFirstSegments() {
+ final double[] fSegBuf = firstSegmentsBuffer;
+
+ for (int i = 0; i < firstSegidx; ) {
+ int type = (int)fSegBuf[i];
+ emitSeg(fSegBuf, i + 1, type);
+ i += (type - 1);
+ }
+ firstSegidx = 0;
+ }
+ // We don't emit the first dash right away. If we did, caps would be
+ // drawn on it, but we need joins to be drawn if there's a closePath()
+ // So, we store the path elements that make up the first dash in the
+ // buffer below.
+ private double[] firstSegmentsBuffer; // dynamic array
+ private int firstSegidx;
+
+ // precondition: pts must be in relative coordinates (relative to x0,y0)
+ private void goTo(double[] pts, int off, final int type) {
+ double x = pts[off + type - 4];
+ double y = pts[off + type - 3];
+ if (dashOn) {
+ if (starting) {
+ int len = type - 1; // - 2 + 1
+ int segIdx = firstSegidx;
+ double[] buf = firstSegmentsBuffer;
+ if (segIdx + len > buf.length) {
+ if (DO_STATS) {
+ rdrCtx.stats.stat_array_dasher_firstSegmentsBuffer
+ .add(segIdx + len);
+ }
+ firstSegmentsBuffer = buf
+ = firstSegmentsBuffer_ref.widenArray(buf, segIdx,
+ segIdx + len);
+ }
+ buf[segIdx++] = type;
+ len--;
+ // small arraycopy (2, 4 or 6) but with offset:
+ System.arraycopy(pts, off, buf, segIdx, len);
+ segIdx += len;
+ firstSegidx = segIdx;
+ } else {
+ if (needsMoveTo) {
+ out.moveTo(x0, y0);
+ needsMoveTo = false;
+ }
+ emitSeg(pts, off, type);
+ }
+ } else {
+ starting = false;
+ needsMoveTo = true;
+ }
+ this.x0 = x;
+ this.y0 = y;
+ }
+
+ @Override
+ public void lineTo(double x1, double y1) {
+ double dx = x1 - x0;
+ double dy = y1 - y0;
+
+ double len = dx*dx + dy*dy;
+ if (len == 0.0d) {
+ return;
+ }
+ len = Math.sqrt(len);
+
+ // The scaling factors needed to get the dx and dy of the
+ // transformed dash segments.
+ final double cx = dx / len;
+ final double cy = dy / len;
+
+ final double[] _curCurvepts = curCurvepts;
+ final double[] _dash = dash;
+
+ double leftInThisDashSegment;
+ double dashdx, dashdy, p;
+
+ while (true) {
+ leftInThisDashSegment = _dash[idx] - phase;
+
+ if (len <= leftInThisDashSegment) {
+ _curCurvepts[0] = x1;
+ _curCurvepts[1] = y1;
+ goTo(_curCurvepts, 0, 4);
+
+ // Advance phase within current dash segment
+ phase += len;
+ // TODO: compare double values using epsilon:
+ if (len == leftInThisDashSegment) {
+ phase = 0.0d;
+ idx = (idx + 1) % dashLen;
+ dashOn = !dashOn;
+ }
+ return;
+ }
+
+ dashdx = _dash[idx] * cx;
+ dashdy = _dash[idx] * cy;
+
+ if (phase == 0.0d) {
+ _curCurvepts[0] = x0 + dashdx;
+ _curCurvepts[1] = y0 + dashdy;
+ } else {
+ p = leftInThisDashSegment / _dash[idx];
+ _curCurvepts[0] = x0 + p * dashdx;
+ _curCurvepts[1] = y0 + p * dashdy;
+ }
+
+ goTo(_curCurvepts, 0, 4);
+
+ len -= leftInThisDashSegment;
+ // Advance to next dash segment
+ idx = (idx + 1) % dashLen;
+ dashOn = !dashOn;
+ phase = 0.0d;
+ }
+ }
+
+ // shared instance in DDasher
+ private final LengthIterator li = new LengthIterator();
+
+ // preconditions: curCurvepts must be an array of length at least 2 * type,
+ // that contains the curve we want to dash in the first type elements
+ private void somethingTo(int type) {
+ if (pointCurve(curCurvepts, type)) {
+ return;
+ }
+ li.initializeIterationOnCurve(curCurvepts, type);
+
+ // initially the current curve is at curCurvepts[0...type]
+ int curCurveoff = 0;
+ double lastSplitT = 0.0d;
+ double t;
+ double leftInThisDashSegment = dash[idx] - phase;
+
+ while ((t = li.next(leftInThisDashSegment)) < 1.0d) {
+ if (t != 0.0d) {
+ DHelpers.subdivideAt((t - lastSplitT) / (1.0d - lastSplitT),
+ curCurvepts, curCurveoff,
+ curCurvepts, 0,
+ curCurvepts, type, type);
+ lastSplitT = t;
+ goTo(curCurvepts, 2, type);
+ curCurveoff = type;
+ }
+ // Advance to next dash segment
+ idx = (idx + 1) % dashLen;
+ dashOn = !dashOn;
+ phase = 0.0d;
+ leftInThisDashSegment = dash[idx];
+ }
+ goTo(curCurvepts, curCurveoff+2, type);
+ phase += li.lastSegLen();
+ if (phase >= dash[idx]) {
+ phase = 0.0d;
+ idx = (idx + 1) % dashLen;
+ dashOn = !dashOn;
+ }
+ // reset LengthIterator:
+ li.reset();
+ }
+
+ private static boolean pointCurve(double[] curve, int type) {
+ for (int i = 2; i < type; i++) {
+ if (curve[i] != curve[i-2]) {
+ return false;
+ }
+ }
+ return true;
+ }
+
+ // Objects of this class are used to iterate through curves. They return
+ // t values where the left side of the curve has a specified length.
+ // It does this by subdividing the input curve until a certain error
+ // condition has been met. A recursive subdivision procedure would
+ // return as many as 1<