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42 #include "qtriangulatingstroker_p.h"
47 #define CURVE_FLATNESS Q_PI / 8
52 void QTriangulatingStroker::endCapOrJoinClosed(const qreal *start, const qreal *cur,
53 bool implicitClose, bool endsAtStart)
57 } else if (implicitClose) {
64 int count = m_vertices.size();
66 // Copy the (x, y) values because QDataBuffer::add(const float& t)
67 // may resize the buffer, which will leave t pointing at the
68 // previous buffer's memory region if we don't copy first.
69 float x = m_vertices.at(count-2);
70 float y = m_vertices.at(count-1);
75 static inline void skipDuplicatePoints(const qreal **pts, const qreal *endPts)
77 while ((*pts + 2) < endPts && float((*pts)[0]) == float((*pts)[2])
78 && float((*pts)[1]) == float((*pts)[3]))
84 void QTriangulatingStroker::process(const QVectorPath &path, const QPen &pen, const QRectF &)
86 const qreal *pts = path.points();
87 const QPainterPath::ElementType *types = path.elements();
88 int count = path.elementCount();
92 float realWidth = qpen_widthf(pen);
96 m_width = realWidth / 2;
98 bool cosmetic = pen.isCosmetic();
100 m_width = m_width * m_inv_scale;
103 m_join_style = qpen_joinStyle(pen);
104 m_cap_style = qpen_capStyle(pen);
106 m_miter_limit = pen.miterLimit() * qpen_widthf(pen);
108 // The curvyness is based on the notion that I originally wanted
109 // roughly one line segment pr 4 pixels. This may seem little, but
110 // because we sample at constantly incrementing B(t) E [0<t<1], we
111 // will get longer segments where the curvature is small and smaller
112 // segments when the curvature is high.
114 // To get a rough idea of the length of each curve, I pretend that
115 // the curve is a 90 degree arc, whose radius is
116 // qMax(curveBounds.width, curveBounds.height). Based on this
117 // logic we can estimate the length of the outline edges based on
118 // the radius + a pen width and adjusting for scale factors
119 // depending on if the pen is cosmetic or not.
121 // The curvyness value of PI/14 was based on,
122 // arcLength = 2*PI*r/4 = PI*r/2 and splitting length into somewhere
123 // between 3 and 8 where 5 seemed to be give pretty good results
124 // hence: Q_PI/14. Lower divisors will give more detail at the
125 // direct cost of performance.
127 // simplfy pens that are thin in device size (2px wide or less)
128 if (realWidth < 2.5 && (cosmetic || m_inv_scale == 1)) {
129 if (m_cap_style == Qt::RoundCap)
130 m_cap_style = Qt::SquareCap;
131 if (m_join_style == Qt::RoundJoin)
132 m_join_style = Qt::MiterJoin;
133 m_curvyness_add = 0.5;
134 m_curvyness_mul = CURVE_FLATNESS / m_inv_scale;
136 } else if (cosmetic) {
137 m_curvyness_add = realWidth / 2;
138 m_curvyness_mul = CURVE_FLATNESS;
139 m_roundness = qMax<int>(4, realWidth * CURVE_FLATNESS);
141 m_curvyness_add = m_width;
142 m_curvyness_mul = CURVE_FLATNESS / m_inv_scale;
143 m_roundness = qMax<int>(4, realWidth * m_curvyness_mul);
146 // Over this level of segmentation, there doesn't seem to be any
147 // benefit, even for huge penWidth
148 if (m_roundness > 24)
151 m_sin_theta = qFastSin(Q_PI / m_roundness);
152 m_cos_theta = qFastCos(Q_PI / m_roundness);
154 const qreal *endPts = pts + (count<<1);
155 const qreal *startPts = 0;
157 Qt::PenCapStyle cap = m_cap_style;
160 skipDuplicatePoints(&pts, endPts);
161 if ((pts + 2) == endPts)
166 bool endsAtStart = float(startPts[0]) == float(endPts[-2])
167 && float(startPts[1]) == float(endPts[-1]);
169 if (endsAtStart || path.hasImplicitClose())
170 m_cap_style = Qt::FlatCap;
174 skipDuplicatePoints(&pts, endPts);
177 skipDuplicatePoints(&pts, endPts);
178 while (pts < endPts) {
182 skipDuplicatePoints(&pts, endPts);
184 endCapOrJoinClosed(startPts, pts-2, path.hasImplicitClose(), endsAtStart);
187 bool endsAtStart = false;
188 QPainterPath::ElementType previousType = QPainterPath::MoveToElement;
189 const qreal *previousPts = pts;
190 while (pts < endPts) {
192 case QPainterPath::MoveToElement: {
193 if (previousType != QPainterPath::MoveToElement)
194 endCapOrJoinClosed(startPts, previousPts, path.hasImplicitClose(), endsAtStart);
197 skipDuplicatePoints(&startPts, endPts); // Skip duplicates to find correct normal.
198 if (startPts + 2 >= endPts)
199 return; // Nothing to see here...
201 int end = (endPts - pts) / 2;
202 int i = 2; // Start looking to ahead since we never have two moveto's in a row
203 while (i<end && types[i] != QPainterPath::MoveToElement) {
206 endsAtStart = float(startPts[0]) == float(pts[i*2 - 2])
207 && float(startPts[1]) == float(pts[i*2 - 1]);
208 if (endsAtStart || path.hasImplicitClose())
209 m_cap_style = Qt::FlatCap;
213 previousType = QPainterPath::MoveToElement;
218 case QPainterPath::LineToElement:
219 if (float(m_cx) != float(pts[0]) || float(m_cy) != float(pts[1])) {
220 if (previousType != QPainterPath::MoveToElement)
223 previousType = QPainterPath::LineToElement;
229 case QPainterPath::CurveToElement:
230 if (float(m_cx) != float(pts[0]) || float(m_cy) != float(pts[1])
231 || float(pts[0]) != float(pts[2]) || float(pts[1]) != float(pts[3])
232 || float(pts[2]) != float(pts[4]) || float(pts[3]) != float(pts[5]))
234 if (float(m_cx) != float(pts[0]) || float(m_cy) != float(pts[1])) {
235 if (previousType != QPainterPath::MoveToElement)
239 previousType = QPainterPath::CurveToElement;
240 previousPts = pts + 4;
251 if (previousType != QPainterPath::MoveToElement)
252 endCapOrJoinClosed(startPts, previousPts, path.hasImplicitClose(), endsAtStart);
256 void QTriangulatingStroker::moveTo(const qreal *pts)
263 normalVector(m_cx, m_cy, x2, y2, &m_nvx, &m_nvy);
266 // To acheive jumps we insert zero-area tringles. This is done by
267 // adding two identical points in both the end of previous strip
268 // and beginning of next strip
269 bool invisibleJump = m_vertices.size();
271 switch (m_cap_style) {
274 m_vertices.add(m_cx + m_nvx);
275 m_vertices.add(m_cy + m_nvy);
278 case Qt::SquareCap: {
279 float sx = m_cx - m_nvy;
280 float sy = m_cy + m_nvx;
282 m_vertices.add(sx + m_nvx);
283 m_vertices.add(sy + m_nvy);
285 emitLineSegment(sx, sy, m_nvx, m_nvy);
288 QVarLengthArray<float> points;
289 arcPoints(m_cx, m_cy, m_cx + m_nvx, m_cy + m_nvy, m_cx - m_nvx, m_cy - m_nvy, points);
290 m_vertices.resize(m_vertices.size() + points.size() + 2 * int(invisibleJump));
291 int count = m_vertices.size();
293 int end = points.size() / 2;
294 while (front != end) {
295 m_vertices.at(--count) = points[2 * end - 1];
296 m_vertices.at(--count) = points[2 * end - 2];
300 m_vertices.at(--count) = points[2 * front + 1];
301 m_vertices.at(--count) = points[2 * front + 0];
306 m_vertices.at(count - 1) = m_vertices.at(count + 1);
307 m_vertices.at(count - 2) = m_vertices.at(count + 0);
310 default: break; // ssssh gcc...
312 emitLineSegment(m_cx, m_cy, m_nvx, m_nvy);
315 void QTriangulatingStroker::cubicTo(const qreal *pts)
317 const QPointF *p = (const QPointF *) pts;
318 QBezier bezier = QBezier::fromPoints(*(p - 1), p[0], p[1], p[2]);
320 QRectF bounds = bezier.bounds();
321 float rad = qMax(bounds.width(), bounds.height());
322 int threshold = qMin<float>(64, (rad + m_curvyness_add) * m_curvyness_mul);
325 qreal threshold_minus_1 = threshold - 1;
328 float cx = m_cx, cy = m_cy;
331 for (int i=1; i<threshold; ++i) {
332 qreal t = qreal(i) / threshold_minus_1;
333 QPointF p = bezier.pointAt(t);
337 normalVector(cx, cy, x, y, &vx, &vy);
339 emitLineSegment(x, y, vx, vy);
352 void QTriangulatingStroker::join(const qreal *pts)
354 // Creates a join to the next segment (m_cx, m_cy) -> (pts[0], pts[1])
355 normalVector(m_cx, m_cy, pts[0], pts[1], &m_nvx, &m_nvy);
357 switch (m_join_style) {
360 case Qt::SvgMiterJoin:
361 case Qt::MiterJoin: {
362 // Find out on which side the join should be.
363 int count = m_vertices.size();
364 float prevNvx = m_vertices.at(count - 2) - m_cx;
365 float prevNvy = m_vertices.at(count - 1) - m_cy;
366 float xprod = prevNvx * m_nvy - prevNvy * m_nvx;
367 float px, py, qx, qy;
369 // If the segments are parallel, use bevel join.
370 if (qFuzzyIsNull(xprod))
373 // Find the corners of the previous and next segment to join.
375 px = m_vertices.at(count - 2);
376 py = m_vertices.at(count - 1);
380 px = m_vertices.at(count - 4);
381 py = m_vertices.at(count - 3);
386 // Find intersection point.
387 float pu = px * prevNvx + py * prevNvy;
388 float qv = qx * m_nvx + qy * m_nvy;
389 float ix = (m_nvy * pu - prevNvy * qv) / xprod;
390 float iy = (prevNvx * qv - m_nvx * pu) / xprod;
392 // Check that the distance to the intersection point is less than the miter limit.
393 if ((ix - px) * (ix - px) + (iy - py) * (iy - py) <= m_miter_limit * m_miter_limit) {
400 // Do a plain bevel join if the miter limit is exceeded or if
401 // the lines are parallel. This is not what the raster
402 // engine's stroker does, but it is both faster and similar to
403 // what some other graphics API's do.
406 case Qt::RoundJoin: {
407 QVarLengthArray<float> points;
408 int count = m_vertices.size();
409 float prevNvx = m_vertices.at(count - 2) - m_cx;
410 float prevNvy = m_vertices.at(count - 1) - m_cy;
411 if (m_nvx * prevNvy - m_nvy * prevNvx < 0) {
412 arcPoints(0, 0, m_nvx, m_nvy, -prevNvx, -prevNvy, points);
413 for (int i = points.size() / 2; i > 0; --i)
414 emitLineSegment(m_cx, m_cy, points[2 * i - 2], points[2 * i - 1]);
416 arcPoints(0, 0, -prevNvx, -prevNvy, m_nvx, m_nvy, points);
417 for (int i = 0; i < points.size() / 2; ++i)
418 emitLineSegment(m_cx, m_cy, points[2 * i + 0], points[2 * i + 1]);
421 default: break; // gcc warn--
424 emitLineSegment(m_cx, m_cy, m_nvx, m_nvy);
427 void QTriangulatingStroker::endCap(const qreal *)
429 switch (m_cap_style) {
433 emitLineSegment(m_cx + m_nvy, m_cy - m_nvx, m_nvx, m_nvy);
436 QVarLengthArray<float> points;
437 int count = m_vertices.size();
438 arcPoints(m_cx, m_cy, m_vertices.at(count - 2), m_vertices.at(count - 1), m_vertices.at(count - 4), m_vertices.at(count - 3), points);
440 int end = points.size() / 2;
441 while (front != end) {
442 m_vertices.add(points[2 * end - 2]);
443 m_vertices.add(points[2 * end - 1]);
447 m_vertices.add(points[2 * front + 0]);
448 m_vertices.add(points[2 * front + 1]);
452 default: break; // to shut gcc up...
456 void QTriangulatingStroker::arcPoints(float cx, float cy, float fromX, float fromY, float toX, float toY, QVarLengthArray<float> &points)
458 float dx1 = fromX - cx;
459 float dy1 = fromY - cy;
460 float dx2 = toX - cx;
461 float dy2 = toY - cy;
463 // while more than 180 degrees left:
464 while (dx1 * dy2 - dx2 * dy1 < 0) {
465 float tmpx = dx1 * m_cos_theta - dy1 * m_sin_theta;
466 float tmpy = dx1 * m_sin_theta + dy1 * m_cos_theta;
469 points.append(cx + dx1);
470 points.append(cy + dy1);
473 // while more than 90 degrees left:
474 while (dx1 * dx2 + dy1 * dy2 < 0) {
475 float tmpx = dx1 * m_cos_theta - dy1 * m_sin_theta;
476 float tmpy = dx1 * m_sin_theta + dy1 * m_cos_theta;
479 points.append(cx + dx1);
480 points.append(cy + dy1);
483 // while more than 0 degrees left:
484 while (dx1 * dy2 - dx2 * dy1 > 0) {
485 float tmpx = dx1 * m_cos_theta - dy1 * m_sin_theta;
486 float tmpy = dx1 * m_sin_theta + dy1 * m_cos_theta;
489 points.append(cx + dx1);
490 points.append(cy + dy1);
493 // remove last point which was rotated beyond [toX, toY].
494 if (!points.isEmpty())
495 points.resize(points.size() - 2);
498 static void qdashprocessor_moveTo(qreal x, qreal y, void *data)
500 ((QDashedStrokeProcessor *) data)->addElement(QPainterPath::MoveToElement, x, y);
503 static void qdashprocessor_lineTo(qreal x, qreal y, void *data)
505 ((QDashedStrokeProcessor *) data)->addElement(QPainterPath::LineToElement, x, y);
508 static void qdashprocessor_cubicTo(qreal, qreal, qreal, qreal, qreal, qreal, void *)
510 Q_ASSERT(0); // The dasher should not produce curves...
513 QDashedStrokeProcessor::QDashedStrokeProcessor()
514 : m_points(0), m_types(0),
515 m_dash_stroker(0), m_inv_scale(1)
517 m_dash_stroker.setMoveToHook(qdashprocessor_moveTo);
518 m_dash_stroker.setLineToHook(qdashprocessor_lineTo);
519 m_dash_stroker.setCubicToHook(qdashprocessor_cubicTo);
522 void QDashedStrokeProcessor::process(const QVectorPath &path, const QPen &pen, const QRectF &clip)
525 const qreal *pts = path.points();
526 const QPainterPath::ElementType *types = path.elements();
527 int count = path.elementCount();
529 bool cosmetic = pen.isCosmetic();
533 m_points.reserve(path.elementCount());
534 m_types.reserve(path.elementCount());
536 qreal width = qpen_widthf(pen);
540 m_dash_stroker.setDashPattern(pen.dashPattern());
541 m_dash_stroker.setStrokeWidth(cosmetic ? width * m_inv_scale : width);
542 m_dash_stroker.setDashOffset(pen.dashOffset());
543 m_dash_stroker.setMiterLimit(pen.miterLimit());
544 m_dash_stroker.setClipRect(clip);
546 float curvynessAdd, curvynessMul;
548 // simplify pens that are thin in device size (2px wide or less)
549 if (width < 2.5 && (cosmetic || m_inv_scale == 1)) {
551 curvynessMul = CURVE_FLATNESS / m_inv_scale;
552 } else if (cosmetic) {
553 curvynessAdd= width / 2;
554 curvynessMul= CURVE_FLATNESS;
556 curvynessAdd = width * m_inv_scale;
557 curvynessMul = CURVE_FLATNESS / m_inv_scale;
563 const qreal *endPts = pts + (count<<1);
565 m_dash_stroker.begin(this);
568 m_dash_stroker.moveTo(pts[0], pts[1]);
570 while (pts < endPts) {
571 m_dash_stroker.lineTo(pts[0], pts[1]);
575 while (pts < endPts) {
577 case QPainterPath::MoveToElement:
578 m_dash_stroker.moveTo(pts[0], pts[1]);
582 case QPainterPath::LineToElement:
583 m_dash_stroker.lineTo(pts[0], pts[1]);
587 case QPainterPath::CurveToElement: {
588 QBezier b = QBezier::fromPoints(*(((const QPointF *) pts) - 1),
589 *(((const QPointF *) pts)),
590 *(((const QPointF *) pts) + 1),
591 *(((const QPointF *) pts) + 2));
592 QRectF bounds = b.bounds();
593 float rad = qMax(bounds.width(), bounds.height());
594 int threshold = qMin<float>(64, (rad + curvynessAdd) * curvynessMul);
598 qreal threshold_minus_1 = threshold - 1;
599 for (int i=0; i<threshold; ++i) {
600 QPointF pt = b.pointAt(i / threshold_minus_1);
601 m_dash_stroker.lineTo(pt.x(), pt.y());
611 m_dash_stroker.end();