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    41 

    42 #include "qtriangulatingstroker_p.h"

    43 #include <qmath.h>

    44 

    45 

    46 #define CURVE_FLATNESS Q_PI / 8

    47 

    48 

    49 

    50 

    51 void QTriangulatingStroker::endCapOrJoinClosed(const qreal *start, const qreal *cur,

    52                                                bool implicitClose, bool endsAtStart)

    53 {

    54     if (endsAtStart) {

    55         join(start + 2);

    56     } else if (implicitClose) {

    57         join(start);

    58         lineTo(start);

    59         join(start+2);

    60     } else {

    61         endCap(cur);

    62     }

    63 }

    64 

    65 

    66 void QTriangulatingStroker::process(const QVectorPath &path, const QPen &pen)

    67 {

    68     const qreal *pts = path.points();

    69     const QPainterPath::ElementType *types = path.elements();

    70     int count = path.elementCount();

    71     if (count < 2)

    72         return;

    73 

    74     float realWidth = qpen_widthf(pen);

    75     if (realWidth == 0)

    76         realWidth = 1;

    77 

    78     m_width = realWidth / 2;

    79 

    80     bool cosmetic = pen.isCosmetic();

    81     if (cosmetic) {

    82         m_width = m_width * m_inv_scale;

    83     }

    84 

    85     m_join_style = qpen_joinStyle(pen);

    86     m_cap_style = qpen_capStyle(pen);

    87     m_vertices.reset();

    88     m_miter_limit = pen.miterLimit() * qpen_widthf(pen);

    89 

    90     // The curvyness is based on the notion that I originally wanted

    91     // roughly one line segment pr 4 pixels. This may seem little, but

    92     // because we sample at constantly incrementing B(t) E [0<t<1], we

    93     // will get longer segments where the curvature is small and smaller

    94     // segments when the curvature is high.

    95     //

    96     // To get a rough idea of the length of each curve, I pretend that

    97     // the curve is a 90 degree arc, whose radius is

    98     // qMax(curveBounds.width, curveBounds.height). Based on this

    99     // logic we can estimate the length of the outline edges based on

   100     // the radius + a pen width and adjusting for scale factors

   101     // depending on if the pen is cosmetic or not.

   102     //

   103     // The curvyness value of PI/14 was based on,

   104     // arcLength=2*PI*r/4=PI/2 and splitting length into somewhere

   105     // between 3 and 8 where 5 seemed to be give pretty good results

   106     // hence: Q_PI/14. Lower divisors will give more detail at the

   107     // direct cost of performance.

   108 

   109     // simplfy pens that are thin in device size (2px wide or less)

   110     if (realWidth < 2.5 && (cosmetic || m_inv_scale == 1)) {

   111         if (m_cap_style == Qt::RoundCap)

   112             m_cap_style = Qt::SquareCap;

   113         if (m_join_style == Qt::RoundJoin)

   114             m_join_style = Qt::MiterJoin;

   115         m_curvyness_add = 0.5;

   116         m_curvyness_mul = CURVE_FLATNESS;

   117         m_roundness = 1;

   118     } else if (cosmetic) {

   119         m_curvyness_add = realWidth / 2;

   120         m_curvyness_mul = CURVE_FLATNESS;

   121         m_roundness = qMax<int>(4, realWidth * CURVE_FLATNESS);

   122     } else {

   123         m_curvyness_add = m_width;

   124         m_curvyness_mul = CURVE_FLATNESS / m_inv_scale;

   125         m_roundness = qMax<int>(4, realWidth * m_curvyness_mul);

   126     }

   127 

   128     // Over this level of segmentation, there doesn't seem to be any

   129     // benefit, even for huge penWidth

   130     if (m_roundness > 24)

   131         m_roundness = 24;

   132 

   133     m_sin_theta = qSin(Q_PI / m_roundness); // ### Use qFastSin

   134     m_cos_theta = qCos(Q_PI / m_roundness);

   135 

   136     const qreal *endPts = pts + (count<<1);

   137     const qreal *startPts;

   138 

   139     Qt::PenCapStyle cap = m_cap_style;

   140 

   141     if (!types) {

   142         startPts = pts;

   143 

   144         bool endsAtStart = startPts[0] == *(endPts-2) && startPts[1] == *(endPts-1);

   145 

   146         Qt::PenCapStyle cap = m_cap_style;

   147         if (endsAtStart || path.hasImplicitClose())

   148             m_cap_style = Qt::FlatCap;

   149         moveTo(pts);

   150         m_cap_style = cap;

   151         pts += 2;

   152         lineTo(pts);

   153         pts += 2;

   154         while (pts < endPts) {

   155             join(pts);

   156             lineTo(pts);

   157             pts += 2;

   158         }

   159 

   160         endCapOrJoinClosed(startPts, pts-2, path.hasImplicitClose(), endsAtStart);

   161 

   162     } else {

   163         bool endsAtStart;

   164         while (pts < endPts) {

   165             switch (*types) {

   166             case QPainterPath::MoveToElement: {

   167                 if (pts != path.points())

   168                     endCapOrJoinClosed(startPts, pts, path.hasImplicitClose(), endsAtStart);

   169 

   170                 startPts = pts;

   171                 int end = (endPts - pts) / 2;

   172                 int i = 2; // Start looking to ahead since we never have two moveto's in a row

   173                 while (i<end && types[i] != QPainterPath::MoveToElement) {

   174                     ++i;

   175                 }

   176                 endsAtStart = startPts[0] == pts[i*2 - 2] && startPts[1] == pts[i*2 - 1];

   177                 if (endsAtStart || path.hasImplicitClose())

   178                     m_cap_style = Qt::FlatCap;

   179 

   180                 moveTo(pts);

   181                 m_cap_style = cap;

   182                 pts+=2;

   183                 ++types;

   184                 break; }

   185             case QPainterPath::LineToElement:

   186                 if (*(types - 1) != QPainterPath::MoveToElement)

   187                     join(pts);

   188                 lineTo(pts);

   189                 pts+=2;

   190                 ++types;

   191                 break;

   192             case QPainterPath::CurveToElement:

   193                 if (*(types - 1) != QPainterPath::MoveToElement)

   194                     join(pts);

   195                 cubicTo(pts);

   196                 pts+=6;

   197                 types+=3;

   198                 break;

   199             default:

   200                 Q_ASSERT(false);

   201                 break;

   202             }

   203         }

   204 

   205         endCapOrJoinClosed(startPts, pts-2, path.hasImplicitClose(), endsAtStart);

   206     }

   207 }

   208 

   209 void QTriangulatingStroker::cubicTo(const qreal *pts)

   210 {

   211     const QPointF *p = (const QPointF *) pts;

   212     QBezier bezier = QBezier::fromPoints(*(p - 1), p[0], p[1], p[2]);

   213 

   214     QRectF bounds = bezier.bounds();

   215     float rad = qMax(bounds.width(), bounds.height());

   216     int threshold = qMin<float>(64, (rad + m_curvyness_add) * m_curvyness_mul);

   217     if (threshold < 4)

   218         threshold = 4;

   219     qreal threshold_minus_1 = threshold - 1;

   220     float vx, vy;

   221 

   222     float cx = m_cx, cy = m_cy;

   223     float x, y;

   224 

   225     for (int i=1; i<threshold; ++i) {

   226         qreal t = qreal(i) / threshold_minus_1;

   227         QPointF p = bezier.pointAt(t);

   228         x = p.x();

   229         y = p.y();

   230 

   231         normalVector(cx, cy, x, y, &vx, &vy);

   232 

   233         emitLineSegment(x, y, vx, vy);

   234 

   235         cx = x;

   236         cy = y;

   237     }

   238 

   239     m_cx = cx;

   240     m_cy = cy;

   241 

   242     m_nvx = vx;

   243     m_nvy = vy;

   244 }

   245 

   246 

   247 

   248 static void qdashprocessor_moveTo(qreal x, qreal y, void *data)

   249 {

   250     ((QDashedStrokeProcessor *) data)->addElement(QPainterPath::MoveToElement, x, y);

   251 }

   252 

   253 static void qdashprocessor_lineTo(qreal x, qreal y, void *data)

   254 {

   255     ((QDashedStrokeProcessor *) data)->addElement(QPainterPath::LineToElement, x, y);

   256 }

   257 

   258 static void qdashprocessor_cubicTo(qreal, qreal, qreal, qreal, qreal, qreal, void *)

   259 {

   260     Q_ASSERT(0); // The dasher should not produce curves...

   261 }

   262 

   263 QDashedStrokeProcessor::QDashedStrokeProcessor()

   264     : m_dash_stroker(0), m_inv_scale(1)

   265 {

   266     m_dash_stroker.setMoveToHook(qdashprocessor_moveTo);

   267     m_dash_stroker.setLineToHook(qdashprocessor_lineTo);

   268     m_dash_stroker.setCubicToHook(qdashprocessor_cubicTo);

   269 }

   270 

   271 void QDashedStrokeProcessor::process(const QVectorPath &path, const QPen &pen)

   272 {

   273 

   274     const qreal *pts = path.points();

   275     const QPainterPath::ElementType *types = path.elements();

   276     int count = path.elementCount();

   277 

   278     m_points.reset();

   279     m_types.reset();

   280 

   281     qreal width = pen.width();

   282     if (width == 0)

   283         width = 1;

   284 

   285     m_dash_stroker.setDashPattern(pen.dashPattern());

   286     m_dash_stroker.setStrokeWidth(width);

   287     m_dash_stroker.setMiterLimit(pen.miterLimit());

   288     qreal curvyness = sqrt(width) * m_inv_scale / 8;

   289 

   290     if (count < 2)

   291         return;

   292 

   293     const qreal *endPts = pts + (count<<1);

   294 

   295     m_dash_stroker.begin(this);

   296 

   297     if (!types) {

   298         m_dash_stroker.moveTo(pts[0], pts[1]);

   299         pts += 2;

   300         while (pts < endPts) {

   301             m_dash_stroker.lineTo(pts[0], pts[1]);

   302             pts += 2;

   303         }

   304     } else {

   305         while (pts < endPts) {

   306             switch (*types) {

   307             case QPainterPath::MoveToElement:

   308                 m_dash_stroker.moveTo(pts[0], pts[1]);

   309                 pts += 2;

   310                 ++types;

   311                 break;

   312             case QPainterPath::LineToElement:

   313                 m_dash_stroker.lineTo(pts[0], pts[1]);

   314                 pts += 2;

   315                 ++types;

   316                 break;

   317             case QPainterPath::CurveToElement: {

   318                 QBezier b = QBezier::fromPoints(*(((const QPointF *) pts) - 1),

   319                                                 *(((const QPointF *) pts)),

   320                                                 *(((const QPointF *) pts) + 1),

   321                                                 *(((const QPointF *) pts) + 2));

   322                 QRectF bounds = b.bounds();

   323                 int threshold = qMin<float>(64, qMax(bounds.width(), bounds.height()) * curvyness);

   324                 if (threshold < 4)

   325                     threshold = 4;

   326                 qreal threshold_minus_1 = threshold - 1;

   327                 for (int i=0; i<threshold; ++i) {

   328                     QPointF pt = b.pointAt(i / threshold_minus_1);

   329                     m_dash_stroker.lineTo(pt.x(), pt.y());

   330                 }

   331                 pts += 6;

   332                 types += 3;

   333                 break; }

   334             default: break;

   335             }

   336         }

   337     }

   338 

   339     m_dash_stroker.end();

   340 }