diff options
Diffstat (limited to 'src/opengl/gl2paintengineex/qtriangulatingstroker.cpp')
| -rw-r--r-- | src/opengl/gl2paintengineex/qtriangulatingstroker.cpp | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/src/opengl/gl2paintengineex/qtriangulatingstroker.cpp b/src/opengl/gl2paintengineex/qtriangulatingstroker.cpp index 1478b09..c78f73f 100644 --- a/src/opengl/gl2paintengineex/qtriangulatingstroker.cpp +++ b/src/opengl/gl2paintengineex/qtriangulatingstroker.cpp @@ -209,6 +209,65 @@ void QTriangulatingStroker::process(const QVectorPath &path, const QPen &pen) } } +void QTriangulatingStroker::moveTo(const qreal *pts) +{ + m_cx = pts[0]; + m_cy = pts[1]; + + float x2 = pts[2]; + float y2 = pts[3]; + normalVector(m_cx, m_cy, x2, y2, &m_nvx, &m_nvy); + + + // To acheive jumps we insert zero-area tringles. This is done by + // adding two identical points in both the end of previous strip + // and beginning of next strip + bool invisibleJump = m_vertices.size(); + + switch (m_cap_style) { + case Qt::FlatCap: + if (invisibleJump) { + m_vertices.add(m_cx + m_nvx); + m_vertices.add(m_cy + m_nvy); + } + break; + case Qt::SquareCap: { + float sx = m_cx - m_nvy; + float sy = m_cy + m_nvx; + if (invisibleJump) { + m_vertices.add(sx + m_nvx); + m_vertices.add(sy + m_nvy); + } + emitLineSegment(sx, sy, m_nvx, m_nvy); + break; } + case Qt::RoundCap: { + QVarLengthArray<float> points; + arcPoints(m_cx, m_cy, m_cx + m_nvx, m_cy + m_nvy, m_cx - m_nvx, m_cy - m_nvy, points); + m_vertices.resize(m_vertices.size() + points.size() + 2 * int(invisibleJump)); + int count = m_vertices.size(); + int front = 0; + int end = points.size() / 2; + while (front != end) { + m_vertices.at(--count) = points[2 * end - 1]; + m_vertices.at(--count) = points[2 * end - 2]; + --end; + if (front == end) + break; + m_vertices.at(--count) = points[2 * front + 1]; + m_vertices.at(--count) = points[2 * front + 0]; + ++front; + } + + if (invisibleJump) { + m_vertices.at(count - 1) = m_vertices.at(count + 1); + m_vertices.at(count - 2) = m_vertices.at(count + 0); + } + break; } + default: break; // ssssh gcc... + } + emitLineSegment(m_cx, m_cy, m_nvx, m_nvy); +} + void QTriangulatingStroker::cubicTo(const qreal *pts) { const QPointF *p = (const QPointF *) pts; @@ -246,6 +305,151 @@ void QTriangulatingStroker::cubicTo(const qreal *pts) m_nvy = vy; } +void QTriangulatingStroker::join(const qreal *pts) +{ + // Creates a join to the next segment (m_cx, m_cy) -> (pts[0], pts[1]) + normalVector(m_cx, m_cy, pts[0], pts[1], &m_nvx, &m_nvy); + + switch (m_join_style) { + case Qt::BevelJoin: + break; + case Qt::MiterJoin: { + // Find out on which side the join should be. + int count = m_vertices.size(); + float prevNvx = m_vertices.at(count - 2) - m_cx; + float prevNvy = m_vertices.at(count - 1) - m_cy; + float xprod = prevNvx * m_nvy - prevNvy * m_nvx; + float px, py, qx, qy; + + // If the segments are parallel, use bevel join. + if (qFuzzyIsNull(xprod)) + break; + + // Find the corners of the previous and next segment to join. + if (xprod < 0) { + px = m_vertices.at(count - 2); + py = m_vertices.at(count - 1); + qx = m_cx - m_nvx; + qy = m_cy - m_nvy; + } else { + px = m_vertices.at(count - 4); + py = m_vertices.at(count - 3); + qx = m_cx + m_nvx; + qy = m_cy + m_nvy; + } + + // Find intersection point. + float pu = px * prevNvx + py * prevNvy; + float qv = qx * m_nvx + qy * m_nvy; + float ix = (m_nvy * pu - prevNvy * qv) / xprod; + float iy = (prevNvx * qv - m_nvx * pu) / xprod; + + // Check that the distance to the intersection point is less than the miter limit. + if ((ix - px) * (ix - px) + (iy - py) * (iy - py) <= m_miter_limit * m_miter_limit) { + m_vertices.add(ix); + m_vertices.add(iy); + m_vertices.add(ix); + m_vertices.add(iy); + } + // else + // Do a plain bevel join if the miter limit is exceeded or if + // the lines are parallel. This is not what the raster + // engine's stroker does, but it is both faster and similar to + // what some other graphics API's do. + + break; } + case Qt::RoundJoin: { + QVarLengthArray<float> points; + int count = m_vertices.size(); + float prevNvx = m_vertices.at(count - 2) - m_cx; + float prevNvy = m_vertices.at(count - 1) - m_cy; + if (m_nvx * prevNvy - m_nvy * prevNvx < 0) { + arcPoints(0, 0, m_nvx, m_nvy, -prevNvx, -prevNvy, points); + for (int i = points.size() / 2; i > 0; --i) + emitLineSegment(m_cx, m_cy, points[2 * i - 2], points[2 * i - 1]); + } else { + arcPoints(0, 0, -prevNvx, -prevNvy, m_nvx, m_nvy, points); + for (int i = 0; i < points.size() / 2; ++i) + emitLineSegment(m_cx, m_cy, points[2 * i + 0], points[2 * i + 1]); + } + break; } + default: break; // gcc warn-- + } + + emitLineSegment(m_cx, m_cy, m_nvx, m_nvy); +} + +void QTriangulatingStroker::endCap(const qreal *) +{ + switch (m_cap_style) { + case Qt::FlatCap: + break; + case Qt::SquareCap: + emitLineSegment(m_cx + m_nvy, m_cy - m_nvx, m_nvx, m_nvy); + break; + case Qt::RoundCap: { + QVarLengthArray<float> points; + int count = m_vertices.size(); + 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); + int front = 0; + int end = points.size() / 2; + while (front != end) { + m_vertices.add(points[2 * end - 2]); + m_vertices.add(points[2 * end - 1]); + --end; + if (front == end) + break; + m_vertices.add(points[2 * front + 0]); + m_vertices.add(points[2 * front + 1]); + ++front; + } + break; } + default: break; // to shut gcc up... + } +} + +void QTriangulatingStroker::arcPoints(float cx, float cy, float fromX, float fromY, float toX, float toY, QVarLengthArray<float> &points) +{ + float dx1 = fromX - cx; + float dy1 = fromY - cy; + float dx2 = toX - cx; + float dy2 = toY - cy; + + // while more than 180 degrees left: + while (dx1 * dy2 - dx2 * dy1 < 0) { + float tmpx = dx1 * m_cos_theta - dy1 * m_sin_theta; + float tmpy = dx1 * m_sin_theta + dy1 * m_cos_theta; + dx1 = tmpx; + dy1 = tmpy; + points.append(cx + dx1); + points.append(cy + dy1); + } + + // while more than 90 degrees left: + while (dx1 * dx2 + dy1 * dy2 < 0) { + float tmpx = dx1 * m_cos_theta - dy1 * m_sin_theta; + float tmpy = dx1 * m_sin_theta + dy1 * m_cos_theta; + dx1 = tmpx; + dy1 = tmpy; + points.append(cx + dx1); + points.append(cy + dy1); + } + + // while more than 0 degrees left: + while (dx1 * dy2 - dx2 * dy1 > 0) { + float tmpx = dx1 * m_cos_theta - dy1 * m_sin_theta; + float tmpy = dx1 * m_sin_theta + dy1 * m_cos_theta; + dx1 = tmpx; + dy1 = tmpy; + points.append(cx + dx1); + points.append(cy + dy1); + } + + // remove last point which was rotated beyond [toX, toY]. + if (!points.isEmpty()) + points.resize(points.size() - 2); +} + static void qdashprocessor_moveTo(qreal x, qreal y, void *data) { ((QDashedStrokeProcessor *) data)->addElement(QPainterPath::MoveToElement, x, y); |