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#include "qtriangulatingstroker_p.h"
#include <qmath.h>
#define CURVE_FLATNESS Q_PI / 8
void QTriangulatingStroker::endCapOrJoinClosed(const qreal *start, const qreal *cur,
bool implicitClose, bool endsAtStart)
{
if (endsAtStart) {
join(start + 2);
} else if (implicitClose) {
join(start);
lineTo(start);
join(start+2);
} else {
endCap(cur);
}
}
void QTriangulatingStroker::process(const QVectorPath &path, const QPen &pen)
{
const qreal *pts = path.points();
const QPainterPath::ElementType *types = path.elements();
int count = path.elementCount();
if (count < 2)
return;
float realWidth = qpen_widthf(pen);
if (realWidth == 0)
realWidth = 1;
m_width = realWidth / 2;
bool cosmetic = pen.isCosmetic();
if (cosmetic) {
m_width = m_width * m_inv_scale;
}
m_join_style = qpen_joinStyle(pen);
m_cap_style = qpen_capStyle(pen);
m_vertices.reset();
m_miter_limit = pen.miterLimit() * qpen_widthf(pen);
// The curvyness is based on the notion that I originally wanted
// roughly one line segment pr 4 pixels. This may seem little, but
// because we sample at constantly incrementing B(t) E [0<t<1], we
// will get longer segments where the curvature is small and smaller
// segments when the curvature is high.
//
// To get a rough idea of the length of each curve, I pretend that
// the curve is a 90 degree arc, whose radius is
// qMax(curveBounds.width, curveBounds.height). Based on this
// logic we can estimate the length of the outline edges based on
// the radius + a pen width and adjusting for scale factors
// depending on if the pen is cosmetic or not.
//
// The curvyness value of PI/14 was based on,
// arcLength=2*PI*r/4=PI/2 and splitting length into somewhere
// between 3 and 8 where 5 seemed to be give pretty good results
// hence: Q_PI/14. Lower divisors will give more detail at the
// direct cost of performance.
// simplfy pens that are thin in device size (2px wide or less)
if (realWidth < 2.5 && (cosmetic || m_inv_scale == 1)) {
if (m_cap_style == Qt::RoundCap)
m_cap_style = Qt::SquareCap;
if (m_join_style == Qt::RoundJoin)
m_join_style = Qt::MiterJoin;
m_curvyness_add = 0.5;
m_curvyness_mul = CURVE_FLATNESS;
m_roundness = 1;
} else if (cosmetic) {
m_curvyness_add = realWidth / 2;
m_curvyness_mul = CURVE_FLATNESS;
m_roundness = qMax<int>(4, realWidth * CURVE_FLATNESS);
} else {
m_curvyness_add = m_width;
m_curvyness_mul = CURVE_FLATNESS / m_inv_scale;
m_roundness = qMax<int>(4, realWidth * m_curvyness_mul);
}
// Over this level of segmentation, there doesn't seem to be any
// benefit, even for huge penWidth
if (m_roundness > 24)
m_roundness = 24;
m_sin_theta = qSin(Q_PI / m_roundness); // ### Use qFastSin
m_cos_theta = qCos(Q_PI / m_roundness);
const qreal *endPts = pts + (count<<1);
const qreal *startPts;
Qt::PenCapStyle cap = m_cap_style;
if (!types) {
startPts = pts;
bool endsAtStart = startPts[0] == *(endPts-2) && startPts[1] == *(endPts-1);
Qt::PenCapStyle cap = m_cap_style;
if (endsAtStart || path.hasImplicitClose())
m_cap_style = Qt::FlatCap;
moveTo(pts);
m_cap_style = cap;
pts += 2;
lineTo(pts);
pts += 2;
while (pts < endPts) {
join(pts);
lineTo(pts);
pts += 2;
}
endCapOrJoinClosed(startPts, pts-2, path.hasImplicitClose(), endsAtStart);
} else {
bool endsAtStart;
while (pts < endPts) {
switch (*types) {
case QPainterPath::MoveToElement: {
if (pts != path.points())
endCapOrJoinClosed(startPts, pts, path.hasImplicitClose(), endsAtStart);
startPts = pts;
int end = (endPts - pts) / 2;
int i = 2; // Start looking to ahead since we never have two moveto's in a row
while (i<end && types[i] != QPainterPath::MoveToElement) {
++i;
}
endsAtStart = startPts[0] == pts[i*2 - 2] && startPts[1] == pts[i*2 - 1];
if (endsAtStart || path.hasImplicitClose())
m_cap_style = Qt::FlatCap;
moveTo(pts);
m_cap_style = cap;
pts+=2;
++types;
break; }
case QPainterPath::LineToElement:
if (*(types - 1) != QPainterPath::MoveToElement)
join(pts);
lineTo(pts);
pts+=2;
++types;
break;
case QPainterPath::CurveToElement:
if (*(types - 1) != QPainterPath::MoveToElement)
join(pts);
cubicTo(pts);
pts+=6;
types+=3;
break;
default:
Q_ASSERT(false);
break;
}
}
endCapOrJoinClosed(startPts, pts-2, path.hasImplicitClose(), endsAtStart);
}
}
void QTriangulatingStroker::cubicTo(const qreal *pts)
{
const QPointF *p = (const QPointF *) pts;
QBezier bezier = QBezier::fromPoints(*(p - 1), p[0], p[1], p[2]);
QRectF bounds = bezier.bounds();
float rad = qMax(bounds.width(), bounds.height());
int threshold = qMin<float>(64, (rad + m_curvyness_add) * m_curvyness_mul);
if (threshold < 4)
threshold = 4;
qreal threshold_minus_1 = threshold - 1;
float vx, vy;
float cx = m_cx, cy = m_cy;
float x, y;
for (int i=1; i<threshold; ++i) {
qreal t = qreal(i) / threshold_minus_1;
QPointF p = bezier.pointAt(t);
x = p.x();
y = p.y();
normalVector(cx, cy, x, y, &vx, &vy);
emitLineSegment(x, y, vx, vy);
cx = x;
cy = y;
}
m_cx = cx;
m_cy = cy;
m_nvx = vx;
m_nvy = vy;
}
static void qdashprocessor_moveTo(qreal x, qreal y, void *data)
{
((QDashedStrokeProcessor *) data)->addElement(QPainterPath::MoveToElement, x, y);
}
static void qdashprocessor_lineTo(qreal x, qreal y, void *data)
{
((QDashedStrokeProcessor *) data)->addElement(QPainterPath::LineToElement, x, y);
}
static void qdashprocessor_cubicTo(qreal, qreal, qreal, qreal, qreal, qreal, void *)
{
Q_ASSERT(0); // The dasher should not produce curves...
}
QDashedStrokeProcessor::QDashedStrokeProcessor()
: m_dash_stroker(0), m_inv_scale(1)
{
m_dash_stroker.setMoveToHook(qdashprocessor_moveTo);
m_dash_stroker.setLineToHook(qdashprocessor_lineTo);
m_dash_stroker.setCubicToHook(qdashprocessor_cubicTo);
}
void QDashedStrokeProcessor::process(const QVectorPath &path, const QPen &pen)
{
const qreal *pts = path.points();
const QPainterPath::ElementType *types = path.elements();
int count = path.elementCount();
m_points.reset();
m_types.reset();
qreal width = pen.width();
if (width == 0)
width = 1;
m_dash_stroker.setDashPattern(pen.dashPattern());
m_dash_stroker.setStrokeWidth(width);
m_dash_stroker.setMiterLimit(pen.miterLimit());
qreal curvyness = sqrt(width) * m_inv_scale / 8;
if (count < 2)
return;
const qreal *endPts = pts + (count<<1);
m_dash_stroker.begin(this);
if (!types) {
m_dash_stroker.moveTo(pts[0], pts[1]);
pts += 2;
while (pts < endPts) {
m_dash_stroker.lineTo(pts[0], pts[1]);
pts += 2;
}
} else {
while (pts < endPts) {
switch (*types) {
case QPainterPath::MoveToElement:
m_dash_stroker.moveTo(pts[0], pts[1]);
pts += 2;
++types;
break;
case QPainterPath::LineToElement:
m_dash_stroker.lineTo(pts[0], pts[1]);
pts += 2;
++types;
break;
case QPainterPath::CurveToElement: {
QBezier b = QBezier::fromPoints(*(((const QPointF *) pts) - 1),
*(((const QPointF *) pts)),
*(((const QPointF *) pts) + 1),
*(((const QPointF *) pts) + 2));
QRectF bounds = b.bounds();
int threshold = qMin<float>(64, qMax(bounds.width(), bounds.height()) * curvyness);
if (threshold < 4)
threshold = 4;
qreal threshold_minus_1 = threshold - 1;
for (int i=0; i<threshold; ++i) {
QPointF pt = b.pointAt(i / threshold_minus_1);
m_dash_stroker.lineTo(pt.x(), pt.y());
}
pts += 6;
types += 3;
break; }
default: break;
}
}
}
m_dash_stroker.end();
}