131 lines
2.7 KiB
C++
131 lines
2.7 KiB
C++
// Copyright (C) 2016 The Qt Company Ltd.
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// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
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#include "beziercurve.h"
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#include <QtQuick/qsgnode.h>
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#include <QtQuick/qsgflatcolormaterial.h>
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//! [1]
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BezierCurve::BezierCurve(QQuickItem *parent)
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: QQuickItem(parent)
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, m_p1(0, 0)
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, m_p2(1, 0)
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, m_p3(0, 1)
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, m_p4(1, 1)
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, m_segmentCount(32)
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{
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setFlag(ItemHasContents, true);
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}
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//! [1]
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//! [2]
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BezierCurve::~BezierCurve() = default;
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//! [2]
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//! [3]
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void BezierCurve::setP1(const QPointF &p)
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{
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if (p == m_p1)
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return;
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m_p1 = p;
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emit p1Changed(p);
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update();
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}
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//! [3]
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void BezierCurve::setP2(const QPointF &p)
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{
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if (p == m_p2)
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return;
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m_p2 = p;
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emit p2Changed(p);
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update();
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}
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void BezierCurve::setP3(const QPointF &p)
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{
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if (p == m_p3)
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return;
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m_p3 = p;
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emit p3Changed(p);
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update();
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}
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void BezierCurve::setP4(const QPointF &p)
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{
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if (p == m_p4)
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return;
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m_p4 = p;
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emit p4Changed(p);
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update();
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}
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void BezierCurve::setSegmentCount(int count)
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{
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if (m_segmentCount == count)
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return;
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m_segmentCount = count;
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emit segmentCountChanged(count);
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update();
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}
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//! [4]
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QSGNode *BezierCurve::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *)
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{
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QSGGeometryNode *node = nullptr;
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QSGGeometry *geometry = nullptr;
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if (!oldNode) {
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node = new QSGGeometryNode;
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//! [4] //! [5]
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geometry = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), m_segmentCount);
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geometry->setLineWidth(2);
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geometry->setDrawingMode(QSGGeometry::DrawLineStrip);
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node->setGeometry(geometry);
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node->setFlag(QSGNode::OwnsGeometry);
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//! [5] //! [6]
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auto *material = new QSGFlatColorMaterial;
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material->setColor(QColor(255, 0, 0));
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node->setMaterial(material);
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node->setFlag(QSGNode::OwnsMaterial);
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//! [6] //! [7]
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} else {
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node = static_cast<QSGGeometryNode *>(oldNode);
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geometry = node->geometry();
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geometry->allocate(m_segmentCount);
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}
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//! [7]
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//! [8]
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QSizeF itemSize = size();
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QSGGeometry::Point2D *vertices = geometry->vertexDataAsPoint2D();
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for (int i = 0; i < m_segmentCount; ++i) {
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qreal t = i / qreal(m_segmentCount - 1);
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qreal invt = 1 - t;
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QPointF pos = invt * invt * invt * m_p1
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+ 3 * invt * invt * t * m_p2
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+ 3 * invt * t * t * m_p3
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+ t * t * t * m_p4;
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float x = pos.x() * itemSize.width();
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float y = pos.y() * itemSize.height();
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vertices[i].set(x, y);
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}
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node->markDirty(QSGNode::DirtyGeometry);
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//! [8]
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//! [9]
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return node;
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}
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//! [9]
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