1
2/*
3 * Copyright 2011 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9#include "GrAAHairLinePathRenderer.h"
10
11#include "GrContext.h"
12#include "GrDrawState.h"
13#include "GrGpu.h"
14#include "GrIndexBuffer.h"
15#include "GrPathUtils.h"
16#include "SkGeometry.h"
17#include "SkTemplates.h"
18
19namespace {
20// quadratics are rendered as 5-sided polys in order to bound the
21// AA stroke around the center-curve. See comments in push_quad_index_buffer and
22// bloat_quad.
23static const int kVertsPerQuad = 5;
24static const int kIdxsPerQuad = 9;
25
26static const int kVertsPerLineSeg = 4;
27static const int kIdxsPerLineSeg = 6;
28
29static const int kNumQuadsInIdxBuffer = 256;
30static const size_t kQuadIdxSBufize = kIdxsPerQuad *
31                                      sizeof(uint16_t) *
32                                      kNumQuadsInIdxBuffer;
33
34bool push_quad_index_data(GrIndexBuffer* qIdxBuffer) {
35    uint16_t* data = (uint16_t*) qIdxBuffer->lock();
36    bool tempData = NULL == data;
37    if (tempData) {
38        data = new uint16_t[kNumQuadsInIdxBuffer * kIdxsPerQuad];
39    }
40    for (int i = 0; i < kNumQuadsInIdxBuffer; ++i) {
41
42        // Each quadratic is rendered as a five sided polygon. This poly bounds
43        // the quadratic's bounding triangle but has been expanded so that the
44        // 1-pixel wide area around the curve is inside the poly.
45        // If a,b,c are the original control points then the poly a0,b0,c0,c1,a1
46        // that is rendered would look like this:
47        //              b0
48        //              b
49        //
50        //     a0              c0
51        //      a            c
52        //       a1       c1
53        // Each is drawn as three triagnles specified by these 9 indices:
54        int baseIdx = i * kIdxsPerQuad;
55        uint16_t baseVert = (uint16_t)(i * kVertsPerQuad);
56        data[0 + baseIdx] = baseVert + 0; // a0
57        data[1 + baseIdx] = baseVert + 1; // a1
58        data[2 + baseIdx] = baseVert + 2; // b0
59        data[3 + baseIdx] = baseVert + 2; // b0
60        data[4 + baseIdx] = baseVert + 4; // c1
61        data[5 + baseIdx] = baseVert + 3; // c0
62        data[6 + baseIdx] = baseVert + 1; // a1
63        data[7 + baseIdx] = baseVert + 4; // c1
64        data[8 + baseIdx] = baseVert + 2; // b0
65    }
66    if (tempData) {
67        bool ret = qIdxBuffer->updateData(data, kQuadIdxSBufize);
68        delete[] data;
69        return ret;
70    } else {
71        qIdxBuffer->unlock();
72        return true;
73    }
74}
75}
76
77GrPathRenderer* GrAAHairLinePathRenderer::Create(GrContext* context) {
78    const GrIndexBuffer* lIdxBuffer = context->getQuadIndexBuffer();
79    if (NULL == lIdxBuffer) {
80        return NULL;
81    }
82    GrGpu* gpu = context->getGpu();
83    GrIndexBuffer* qIdxBuf = gpu->createIndexBuffer(kQuadIdxSBufize, false);
84    SkAutoTUnref<GrIndexBuffer> qIdxBuffer(qIdxBuf);
85    if (NULL == qIdxBuf ||
86        !push_quad_index_data(qIdxBuf)) {
87        return NULL;
88    }
89    return new GrAAHairLinePathRenderer(context,
90                                        lIdxBuffer,
91                                        qIdxBuf);
92}
93
94GrAAHairLinePathRenderer::GrAAHairLinePathRenderer(
95                                        const GrContext* context,
96                                        const GrIndexBuffer* linesIndexBuffer,
97                                        const GrIndexBuffer* quadsIndexBuffer) {
98    fLinesIndexBuffer = linesIndexBuffer;
99    linesIndexBuffer->ref();
100    fQuadsIndexBuffer = quadsIndexBuffer;
101    quadsIndexBuffer->ref();
102}
103
104GrAAHairLinePathRenderer::~GrAAHairLinePathRenderer() {
105    fLinesIndexBuffer->unref();
106    fQuadsIndexBuffer->unref();
107}
108
109namespace {
110
111typedef SkTArray<SkPoint, true> PtArray;
112#define PREALLOC_PTARRAY(N) SkSTArray<(N),SkPoint, true>
113typedef SkTArray<int, true> IntArray;
114
115// Takes 178th time of logf on Z600 / VC2010
116int get_float_exp(float x) {
117    GR_STATIC_ASSERT(sizeof(int) == sizeof(float));
118#if GR_DEBUG
119    static bool tested;
120    if (!tested) {
121        tested = true;
122        GrAssert(get_float_exp(0.25f) == -2);
123        GrAssert(get_float_exp(0.3f) == -2);
124        GrAssert(get_float_exp(0.5f) == -1);
125        GrAssert(get_float_exp(1.f) == 0);
126        GrAssert(get_float_exp(2.f) == 1);
127        GrAssert(get_float_exp(2.5f) == 1);
128        GrAssert(get_float_exp(8.f) == 3);
129        GrAssert(get_float_exp(100.f) == 6);
130        GrAssert(get_float_exp(1000.f) == 9);
131        GrAssert(get_float_exp(1024.f) == 10);
132        GrAssert(get_float_exp(3000000.f) == 21);
133    }
134#endif
135    const int* iptr = (const int*)&x;
136    return (((*iptr) & 0x7f800000) >> 23) - 127;
137}
138
139// we subdivide the quads to avoid huge overfill
140// if it returns -1 then should be drawn as lines
141int num_quad_subdivs(const SkPoint p[3]) {
142    static const SkScalar gDegenerateToLineTol = SK_Scalar1;
143    static const SkScalar gDegenerateToLineTolSqd =
144        SkScalarMul(gDegenerateToLineTol, gDegenerateToLineTol);
145
146    if (p[0].distanceToSqd(p[1]) < gDegenerateToLineTolSqd ||
147        p[1].distanceToSqd(p[2]) < gDegenerateToLineTolSqd) {
148        return -1;
149    }
150
151    GrScalar dsqd = p[1].distanceToLineBetweenSqd(p[0], p[2]);
152    if (dsqd < gDegenerateToLineTolSqd) {
153        return -1;
154    }
155
156    if (p[2].distanceToLineBetweenSqd(p[1], p[0]) < gDegenerateToLineTolSqd) {
157        return -1;
158    }
159
160    static const int kMaxSub = 4;
161    // tolerance of triangle height in pixels
162    // tuned on windows  Quadro FX 380 / Z600
163    // trade off of fill vs cpu time on verts
164    // maybe different when do this using gpu (geo or tess shaders)
165    static const SkScalar gSubdivTol = 175 * SK_Scalar1;
166
167    if (dsqd <= gSubdivTol*gSubdivTol) {
168        return 0;
169    } else {
170        // subdividing the quad reduces d by 4. so we want x = log4(d/tol)
171        // = log4(d*d/tol*tol)/2
172        // = log2(d*d/tol*tol)
173
174#ifdef SK_SCALAR_IS_FLOAT
175        // +1 since we're ignoring the mantissa contribution.
176        int log = get_float_exp(dsqd/(gSubdivTol*gSubdivTol)) + 1;
177        log = GrMin(GrMax(0, log), kMaxSub);
178        return log;
179#else
180        SkScalar log = SkScalarLog(SkScalarDiv(dsqd,gSubdivTol*gSubdivTol));
181        static const SkScalar conv = SkScalarInvert(SkScalarLog(2));
182        log = SkScalarMul(log, conv);
183        return  GrMin(GrMax(0, SkScalarCeilToInt(log)),kMaxSub);
184#endif
185    }
186}
187
188/**
189 * Generates the lines and quads to be rendered. Lines are always recorded in
190 * device space. We will do a device space bloat to account for the 1pixel
191 * thickness.
192 * Quads are recorded in device space unless m contains
193 * perspective, then in they are in src space. We do this because we will
194 * subdivide large quads to reduce over-fill. This subdivision has to be
195 * performed before applying the perspective matrix.
196 */
197int generate_lines_and_quads(const SkPath& path,
198                             const SkMatrix& m,
199                             const SkVector& translate,
200                             GrIRect clip,
201                             PtArray* lines,
202                             PtArray* quads,
203                             IntArray* quadSubdivCnts) {
204    SkPath::Iter iter(path, false);
205
206    int totalQuadCount = 0;
207    GrRect bounds;
208    GrIRect ibounds;
209
210    bool persp = m.hasPerspective();
211
212    for (;;) {
213        GrPoint pts[4];
214        GrPoint devPts[4];
215        GrPathCmd cmd = (GrPathCmd)iter.next(pts);
216        switch (cmd) {
217            case kMove_PathCmd:
218                break;
219            case kLine_PathCmd:
220                SkPoint::Offset(pts, 2, translate);
221                m.mapPoints(devPts, pts, 2);
222                bounds.setBounds(devPts, 2);
223                bounds.outset(SK_Scalar1, SK_Scalar1);
224                bounds.roundOut(&ibounds);
225                if (SkIRect::Intersects(clip, ibounds)) {
226                    SkPoint* pts = lines->push_back_n(2);
227                    pts[0] = devPts[0];
228                    pts[1] = devPts[1];
229                }
230                break;
231            case kQuadratic_PathCmd:
232                SkPoint::Offset(pts, 3, translate);
233                m.mapPoints(devPts, pts, 3);
234                bounds.setBounds(devPts, 3);
235                bounds.outset(SK_Scalar1, SK_Scalar1);
236                bounds.roundOut(&ibounds);
237                if (SkIRect::Intersects(clip, ibounds)) {
238                    int subdiv = num_quad_subdivs(devPts);
239                    GrAssert(subdiv >= -1);
240                    if (-1 == subdiv) {
241                        SkPoint* pts = lines->push_back_n(4);
242                        pts[0] = devPts[0];
243                        pts[1] = devPts[1];
244                        pts[2] = devPts[1];
245                        pts[3] = devPts[2];
246                    } else {
247                        // when in perspective keep quads in src space
248                        SkPoint* qPts = persp ? pts : devPts;
249                        SkPoint* pts = quads->push_back_n(3);
250                        pts[0] = qPts[0];
251                        pts[1] = qPts[1];
252                        pts[2] = qPts[2];
253                        quadSubdivCnts->push_back() = subdiv;
254                        totalQuadCount += 1 << subdiv;
255                    }
256                }
257            break;
258            case kCubic_PathCmd:
259                SkPoint::Offset(pts, 4, translate);
260                m.mapPoints(devPts, pts, 4);
261                bounds.setBounds(devPts, 4);
262                bounds.outset(SK_Scalar1, SK_Scalar1);
263                bounds.roundOut(&ibounds);
264                if (SkIRect::Intersects(clip, ibounds)) {
265                    PREALLOC_PTARRAY(32) q;
266                    // We convert cubics to quadratics (for now).
267                    // In perspective have to do conversion in src space.
268                    if (persp) {
269                        SkScalar tolScale =
270                            GrPathUtils::scaleToleranceToSrc(SK_Scalar1, m,
271                                                             path.getBounds());
272                        GrPathUtils::convertCubicToQuads(pts, tolScale, &q);
273                    } else {
274                        GrPathUtils::convertCubicToQuads(devPts, SK_Scalar1, &q);
275                    }
276                    for (int i = 0; i < q.count(); i += 3) {
277                        SkPoint* qInDevSpace;
278                        // bounds has to be calculated in device space, but q is
279                        // in src space when there is perspective.
280                        if (persp) {
281                            m.mapPoints(devPts, &q[i], 3);
282                            bounds.setBounds(devPts, 3);
283                            qInDevSpace = devPts;
284                        } else {
285                            bounds.setBounds(&q[i], 3);
286                            qInDevSpace = &q[i];
287                        }
288                        bounds.outset(SK_Scalar1, SK_Scalar1);
289                        bounds.roundOut(&ibounds);
290                        if (SkIRect::Intersects(clip, ibounds)) {
291                            int subdiv = num_quad_subdivs(qInDevSpace);
292                            GrAssert(subdiv >= -1);
293                            if (-1 == subdiv) {
294                                SkPoint* pts = lines->push_back_n(4);
295                                // lines should always be in device coords
296                                pts[0] = qInDevSpace[0];
297                                pts[1] = qInDevSpace[1];
298                                pts[2] = qInDevSpace[1];
299                                pts[3] = qInDevSpace[2];
300                            } else {
301                                SkPoint* pts = quads->push_back_n(3);
302                                // q is already in src space when there is no
303                                // perspective and dev coords otherwise.
304                                pts[0] = q[0 + i];
305                                pts[1] = q[1 + i];
306                                pts[2] = q[2 + i];
307                                quadSubdivCnts->push_back() = subdiv;
308                                totalQuadCount += 1 << subdiv;
309                            }
310                        }
311                    }
312                }
313            break;
314            case kClose_PathCmd:
315                break;
316            case kEnd_PathCmd:
317                return totalQuadCount;
318        }
319    }
320}
321
322struct Vertex {
323    GrPoint fPos;
324    union {
325        struct {
326            GrScalar fA;
327            GrScalar fB;
328            GrScalar fC;
329        } fLine;
330        GrVec   fQuadCoord;
331        struct {
332            GrScalar fBogus[4];
333        };
334    };
335};
336GR_STATIC_ASSERT(sizeof(Vertex) == 3 * sizeof(GrPoint));
337
338void intersect_lines(const SkPoint& ptA, const SkVector& normA,
339                     const SkPoint& ptB, const SkVector& normB,
340                     SkPoint* result) {
341
342    SkScalar lineAW = -normA.dot(ptA);
343    SkScalar lineBW = -normB.dot(ptB);
344
345    SkScalar wInv = SkScalarMul(normA.fX, normB.fY) -
346                    SkScalarMul(normA.fY, normB.fX);
347    wInv = SkScalarInvert(wInv);
348
349    result->fX = SkScalarMul(normA.fY, lineBW) - SkScalarMul(lineAW, normB.fY);
350    result->fX = SkScalarMul(result->fX, wInv);
351
352    result->fY = SkScalarMul(lineAW, normB.fX) - SkScalarMul(normA.fX, lineBW);
353    result->fY = SkScalarMul(result->fY, wInv);
354}
355
356void bloat_quad(const SkPoint qpts[3], const GrMatrix* toDevice,
357                const GrMatrix* toSrc, Vertex verts[kVertsPerQuad]) {
358    GrAssert(!toDevice == !toSrc);
359    // original quad is specified by tri a,b,c
360    SkPoint a = qpts[0];
361    SkPoint b = qpts[1];
362    SkPoint c = qpts[2];
363
364    // this should be in the src space, not dev coords, when we have perspective
365    SkMatrix DevToUV;
366    GrPathUtils::quadDesignSpaceToUVCoordsMatrix(qpts, &DevToUV);
367
368    if (toDevice) {
369        toDevice->mapPoints(&a, 1);
370        toDevice->mapPoints(&b, 1);
371        toDevice->mapPoints(&c, 1);
372    }
373    // make a new poly where we replace a and c by a 1-pixel wide edges orthog
374    // to edges ab and bc:
375    //
376    //   before       |        after
377    //                |              b0
378    //         b      |
379    //                |
380    //                |     a0            c0
381    // a         c    |        a1       c1
382    //
383    // edges a0->b0 and b0->c0 are parallel to original edges a->b and b->c,
384    // respectively.
385    Vertex& a0 = verts[0];
386    Vertex& a1 = verts[1];
387    Vertex& b0 = verts[2];
388    Vertex& c0 = verts[3];
389    Vertex& c1 = verts[4];
390
391    SkVector ab = b;
392    ab -= a;
393    SkVector ac = c;
394    ac -= a;
395    SkVector cb = b;
396    cb -= c;
397
398    // We should have already handled degenerates
399    GrAssert(ab.length() > 0 && cb.length() > 0);
400
401    ab.normalize();
402    SkVector abN;
403    abN.setOrthog(ab, SkVector::kLeft_Side);
404    if (abN.dot(ac) > 0) {
405        abN.negate();
406    }
407
408    cb.normalize();
409    SkVector cbN;
410    cbN.setOrthog(cb, SkVector::kLeft_Side);
411    if (cbN.dot(ac) < 0) {
412        cbN.negate();
413    }
414
415    a0.fPos = a;
416    a0.fPos += abN;
417    a1.fPos = a;
418    a1.fPos -= abN;
419
420    c0.fPos = c;
421    c0.fPos += cbN;
422    c1.fPos = c;
423    c1.fPos -= cbN;
424
425    intersect_lines(a0.fPos, abN, c0.fPos, cbN, &b0.fPos);
426
427    if (toSrc) {
428        toSrc->mapPointsWithStride(&verts[0].fPos, sizeof(Vertex), kVertsPerQuad);
429    }
430    DevToUV.mapPointsWithStride(&verts[0].fQuadCoord,
431                                &verts[0].fPos, sizeof(Vertex), kVertsPerQuad);
432}
433
434void add_quads(const SkPoint p[3],
435               int subdiv,
436               const GrMatrix* toDevice,
437               const GrMatrix* toSrc,
438               Vertex** vert) {
439    GrAssert(subdiv >= 0);
440    if (subdiv) {
441        SkPoint newP[5];
442        SkChopQuadAtHalf(p, newP);
443        add_quads(newP + 0, subdiv-1, toDevice, toSrc, vert);
444        add_quads(newP + 2, subdiv-1, toDevice, toSrc, vert);
445    } else {
446        bloat_quad(p, toDevice, toSrc, *vert);
447        *vert += kVertsPerQuad;
448    }
449}
450
451void add_line(const SkPoint p[2],
452              int rtHeight,
453              const SkMatrix* toSrc,
454              Vertex** vert) {
455    const SkPoint& a = p[0];
456    const SkPoint& b = p[1];
457
458    SkVector orthVec = b;
459    orthVec -= a;
460
461    if (orthVec.setLength(SK_Scalar1)) {
462        orthVec.setOrthog(orthVec);
463
464        // the values we pass down to the frag shader
465        // have to be in y-points-up space;
466        SkVector normal;
467        normal.fX = orthVec.fX;
468        normal.fY = -orthVec.fY;
469        SkPoint aYDown;
470        aYDown.fX = a.fX;
471        aYDown.fY = rtHeight - a.fY;
472
473        SkScalar lineC = -(aYDown.dot(normal));
474        for (int i = 0; i < kVertsPerLineSeg; ++i) {
475            (*vert)[i].fPos = (i < 2) ? a : b;
476            if (0 == i || 3 == i) {
477                (*vert)[i].fPos -= orthVec;
478            } else {
479                (*vert)[i].fPos += orthVec;
480            }
481            (*vert)[i].fLine.fA = normal.fX;
482            (*vert)[i].fLine.fB = normal.fY;
483            (*vert)[i].fLine.fC = lineC;
484        }
485        if (NULL != toSrc) {
486            toSrc->mapPointsWithStride(&(*vert)->fPos,
487                                       sizeof(Vertex),
488                                       kVertsPerLineSeg);
489        }
490    } else {
491        // just make it degenerate and likely offscreen
492        (*vert)[0].fPos.set(SK_ScalarMax, SK_ScalarMax);
493        (*vert)[1].fPos.set(SK_ScalarMax, SK_ScalarMax);
494        (*vert)[2].fPos.set(SK_ScalarMax, SK_ScalarMax);
495        (*vert)[3].fPos.set(SK_ScalarMax, SK_ScalarMax);
496    }
497
498    *vert += kVertsPerLineSeg;
499}
500
501}
502
503bool GrAAHairLinePathRenderer::createGeom(const SkPath& path,
504                                          const GrVec* translate,
505                                          GrDrawTarget* target,
506                                          GrDrawState::StageMask stageMask,
507                                          int* lineCnt,
508                                          int* quadCnt) {
509    const GrDrawState& drawState = target->getDrawState();
510    int rtHeight = drawState.getRenderTarget()->height();
511
512    GrIRect clip;
513    if (target->getClip().hasConservativeBounds()) {
514        GrRect clipRect =  target->getClip().getConservativeBounds();
515        clipRect.roundOut(&clip);
516    } else {
517        clip.setLargest();
518    }
519
520
521    GrVertexLayout layout = GrDrawTarget::kEdge_VertexLayoutBit;
522    for (int s = 0; s < GrDrawState::kNumStages; ++s) {
523        if ((1 << s) & stageMask) {
524            layout |= GrDrawTarget::StagePosAsTexCoordVertexLayoutBit(s);
525        }
526    }
527
528    GrMatrix viewM = drawState.getViewMatrix();
529
530    PREALLOC_PTARRAY(128) lines;
531    PREALLOC_PTARRAY(128) quads;
532    IntArray qSubdivs;
533    static const GrVec gZeroVec = {0, 0};
534    if (NULL == translate) {
535        translate = &gZeroVec;
536    }
537    *quadCnt = generate_lines_and_quads(path, viewM, *translate, clip,
538                                        &lines, &quads, &qSubdivs);
539
540    *lineCnt = lines.count() / 2;
541    int vertCnt = kVertsPerLineSeg * *lineCnt + kVertsPerQuad * *quadCnt;
542
543    GrAssert(sizeof(Vertex) == GrDrawTarget::VertexSize(layout));
544
545    Vertex* verts;
546    if (!target->reserveVertexSpace(layout, vertCnt, (void**)&verts)) {
547        return false;
548    }
549
550    const GrMatrix* toDevice = NULL;
551    const GrMatrix* toSrc = NULL;
552    GrMatrix ivm;
553
554    if (viewM.hasPerspective()) {
555        if (viewM.invert(&ivm)) {
556            toDevice = &viewM;
557            toSrc = &ivm;
558        }
559    }
560
561    for (int i = 0; i < *lineCnt; ++i) {
562        add_line(&lines[2*i], rtHeight, toSrc, &verts);
563    }
564
565    int unsubdivQuadCnt = quads.count() / 3;
566    for (int i = 0; i < unsubdivQuadCnt; ++i) {
567        GrAssert(qSubdivs[i] >= 0);
568        add_quads(&quads[3*i], qSubdivs[i], toDevice, toSrc, &verts);
569    }
570
571    return true;
572}
573
574bool GrAAHairLinePathRenderer::canDrawPath(const SkPath& path,
575                                           GrPathFill fill,
576                                           const GrDrawTarget* target,
577                                           bool antiAlias) const {
578    if (fill != kHairLine_PathFill || !antiAlias) {
579        return false;
580    }
581
582    static const uint32_t gReqDerivMask = SkPath::kCubic_SegmentMask |
583                                          SkPath::kQuad_SegmentMask;
584    if (!target->getCaps().fShaderDerivativeSupport &&
585        (gReqDerivMask & path.getSegmentMasks())) {
586        return false;
587    }
588    return true;
589}
590
591bool GrAAHairLinePathRenderer::onDrawPath(const SkPath& path,
592                                          GrPathFill fill,
593                                          const GrVec* translate,
594                                          GrDrawTarget* target,
595                                          GrDrawState::StageMask stageMask,
596                                          bool antiAlias) {
597
598    int lineCnt;
599    int quadCnt;
600
601    if (!this->createGeom(path,
602                          translate,
603                          target,
604                          stageMask,
605                          &lineCnt,
606                          &quadCnt)) {
607        return false;
608    }
609
610    GrDrawState* drawState = target->drawState();
611
612    GrDrawTarget::AutoStateRestore asr;
613    if (!drawState->getViewMatrix().hasPerspective()) {
614        asr.set(target);
615        GrMatrix ivm;
616        if (drawState->getViewInverse(&ivm)) {
617            drawState->preConcatSamplerMatrices(stageMask, ivm);
618        }
619        drawState->setViewMatrix(GrMatrix::I());
620    }
621
622    // TODO: See whether rendering lines as degenerate quads improves perf
623    // when we have a mix
624    target->setIndexSourceToBuffer(fLinesIndexBuffer);
625    int lines = 0;
626    int nBufLines = fLinesIndexBuffer->maxQuads();
627    while (lines < lineCnt) {
628        int n = GrMin(lineCnt - lines, nBufLines);
629        drawState->setVertexEdgeType(GrDrawState::kHairLine_EdgeType);
630        target->drawIndexed(kTriangles_PrimitiveType,
631                            kVertsPerLineSeg*lines,    // startV
632                            0,                         // startI
633                            kVertsPerLineSeg*n,        // vCount
634                            kIdxsPerLineSeg*n);        // iCount
635        lines += n;
636    }
637
638    target->setIndexSourceToBuffer(fQuadsIndexBuffer);
639    int quads = 0;
640    while (quads < quadCnt) {
641        int n = GrMin(quadCnt - quads, kNumQuadsInIdxBuffer);
642        drawState->setVertexEdgeType(GrDrawState::kHairQuad_EdgeType);
643        target->drawIndexed(kTriangles_PrimitiveType,
644                            4 * lineCnt + kVertsPerQuad*quads, // startV
645                            0,                                 // startI
646                            kVertsPerQuad*n,                   // vCount
647                            kIdxsPerQuad*n);                   // iCount
648        quads += n;
649    }
650    return true;
651}
652
653