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50 | |
51 | #include "beziercurve.h" |
52 | |
53 | #include <QtQuick/qsgnode.h> |
54 | #include <QtQuick/qsgflatcolormaterial.h> |
55 | |
56 | //! [1] |
57 | BezierCurve::BezierCurve(QQuickItem *parent) |
58 | : QQuickItem(parent) |
59 | , m_p1(0, 0) |
60 | , m_p2(1, 0) |
61 | , m_p3(0, 1) |
62 | , m_p4(1, 1) |
63 | , m_segmentCount(32) |
64 | { |
65 | setFlag(flag: ItemHasContents, enabled: true); |
66 | } |
67 | //! [1] |
68 | |
69 | //! [2] |
70 | BezierCurve::~BezierCurve() |
71 | { |
72 | } |
73 | //! [2] |
74 | |
75 | //! [3] |
76 | void BezierCurve::setP1(const QPointF &p) |
77 | { |
78 | if (p == m_p1) |
79 | return; |
80 | |
81 | m_p1 = p; |
82 | emit p1Changed(p); |
83 | update(); |
84 | } |
85 | //! [3] |
86 | |
87 | void BezierCurve::setP2(const QPointF &p) |
88 | { |
89 | if (p == m_p2) |
90 | return; |
91 | |
92 | m_p2 = p; |
93 | emit p2Changed(p); |
94 | update(); |
95 | } |
96 | |
97 | void BezierCurve::setP3(const QPointF &p) |
98 | { |
99 | if (p == m_p3) |
100 | return; |
101 | |
102 | m_p3 = p; |
103 | emit p3Changed(p); |
104 | update(); |
105 | } |
106 | |
107 | void BezierCurve::setP4(const QPointF &p) |
108 | { |
109 | if (p == m_p4) |
110 | return; |
111 | |
112 | m_p4 = p; |
113 | emit p4Changed(p); |
114 | update(); |
115 | } |
116 | |
117 | void BezierCurve::setSegmentCount(int count) |
118 | { |
119 | if (m_segmentCount == count) |
120 | return; |
121 | |
122 | m_segmentCount = count; |
123 | emit segmentCountChanged(count); |
124 | update(); |
125 | } |
126 | |
127 | //! [4] |
128 | QSGNode *BezierCurve::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *) |
129 | { |
130 | QSGGeometryNode *node = nullptr; |
131 | QSGGeometry *geometry = nullptr; |
132 | |
133 | if (!oldNode) { |
134 | node = new QSGGeometryNode; |
135 | //! [4] //! [5] |
136 | geometry = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), m_segmentCount); |
137 | geometry->setLineWidth(2); |
138 | geometry->setDrawingMode(QSGGeometry::DrawLineStrip); |
139 | node->setGeometry(geometry); |
140 | node->setFlag(QSGNode::OwnsGeometry); |
141 | //! [5] //! [6] |
142 | QSGFlatColorMaterial *material = new QSGFlatColorMaterial; |
143 | material->setColor(QColor(255, 0, 0)); |
144 | node->setMaterial(material); |
145 | node->setFlag(QSGNode::OwnsMaterial); |
146 | //! [6] //! [7] |
147 | } else { |
148 | node = static_cast<QSGGeometryNode *>(oldNode); |
149 | geometry = node->geometry(); |
150 | geometry->allocate(vertexCount: m_segmentCount); |
151 | } |
152 | //! [7] |
153 | |
154 | //! [8] |
155 | QSizeF itemSize = size(); |
156 | QSGGeometry::Point2D *vertices = geometry->vertexDataAsPoint2D(); |
157 | for (int i = 0; i < m_segmentCount; ++i) { |
158 | qreal t = i / qreal(m_segmentCount - 1); |
159 | qreal invt = 1 - t; |
160 | |
161 | QPointF pos = invt * invt * invt * m_p1 |
162 | + 3 * invt * invt * t * m_p2 |
163 | + 3 * invt * t * t * m_p3 |
164 | + t * t * t * m_p4; |
165 | |
166 | float x = pos.x() * itemSize.width(); |
167 | float y = pos.y() * itemSize.height(); |
168 | |
169 | vertices[i].set(nx: x, ny: y); |
170 | } |
171 | node->markDirty(bits: QSGNode::DirtyGeometry); |
172 | //! [8] |
173 | |
174 | |
175 | //! [9] |
176 | return node; |
177 | } |
178 | //! [9] |
179 | |
180 | |