--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/opengl/gl2paintengineex/qtriangulatingstroker.cpp Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,340 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtOpenGL module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#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();
+}