1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
| #include <QApplication>
#include <QWidget>
#include <QLabel>
#include <QSlider>
#include <QLayout>
#include <QPainter>
#include <QMouseEvent>
#include <QSignalMapper>
class Widget: public QWidget {
Q_OBJECT
public:
Widget();
public slots:
// from 0 to 100%
void setT0(int val) { setPart(0, 0.01*val); }
void setT1(int val) { setPart(1, 0.01*val); }
protected:
virtual void paintEvent(QPaintEvent *event);
virtual void mousePressEvent(QMouseEvent *event);
virtual void mouseReleaseEvent(QMouseEvent *event);
virtual void mouseMoveEvent(QMouseEvent *event);
private:
int pointIdx(const QPointF& p);
void updatePart();
void setPart(int idx, qreal val);
QList<QPointF> pts;
QList<QPointF> ptsPart;
qreal t0, t1;
QPointF prev;
int movingIdx;
int overIdx;
};
const qreal r = 5.0;
Widget::Widget()
: t0(0), t1(1), movingIdx(-1), overIdx(-1)
{
setMouseTracking(true);
pts << QPointF(50, 50) << QPointF(450, 100)
<< QPointF(350, 450) << QPointF(750, 500);
ptsPart = pts;
updatePart();
}
void Widget::paintEvent(QPaintEvent *event)
{
Q_UNUSED(event)
QPainter painter(this);
painter.fillRect(0, 0, width(), height(), Qt::darkGray);
painter.setRenderHint(QPainter::Antialiasing);
// draw original bezier
painter.setPen(QPen(QBrush(Qt::white), 1.5));
painter.setBrush(Qt::NoBrush);
QPainterPath path(pts[0]);
path.cubicTo(pts[1], pts[2], pts[3]);
painter.drawPath(path);
// draw path for control points
path = QPainterPath(pts[0]);
path.lineTo(pts[1]);
path.lineTo(pts[2]);
path.lineTo(pts[3]);
QBrush b(Qt::yellow);
painter.setPen(QPen(b, 0.75));
painter.setBrush(Qt::NoBrush);
painter.drawPath(path);
// draw control points
QBrush b1(Qt::cyan);
painter.setPen(Qt::NoPen);
for (int idx = 0; idx < pts.size(); ++idx) {
painter.setBrush(idx == overIdx ? b1 : b);
painter.drawEllipse(pts[idx], r, r);
}
// draw part of original bezier
painter.setPen(QPen(QBrush(QColor(0, 255, 0, 100)), 12.0));
painter.setBrush(Qt::NoBrush);
path = QPainterPath(ptsPart[0]);
path.cubicTo(ptsPart[1], ptsPart[2], ptsPart[3]);
painter.drawPath(path);
}
void Widget::mousePressEvent(QMouseEvent *event)
{
if (movingIdx == -1 && event->button() == Qt::LeftButton) {
movingIdx = pointIdx(event->posF());
prev = event->posF();
}
}
void Widget::mouseReleaseEvent(QMouseEvent *event)
{
if (movingIdx != -1 && event->button() == Qt::LeftButton)
movingIdx = -1;
}
void Widget::mouseMoveEvent(QMouseEvent *event)
{
if (movingIdx != -1) {
pts[movingIdx] += (event->posF() - prev);
updatePart();
prev = event->posF();
update();
} else {
int idx = pointIdx(event->posF());
if (idx != overIdx)
update();
overIdx = idx;
}
}
int Widget::pointIdx(const QPointF& p)
{
for (int idx = 0; idx < pts.size(); ++idx) {
if (QLineF(p, pts[idx]).length() <= 1.2*r)
return idx;
}
return -1;
}
void Widget::updatePart()
{
qreal u0 = 1.0 - t0;
qreal u1 = 1.0 - t1;
qreal x1 = pts[0].x();
qreal y1 = pts[0].y();
qreal x2 = pts[3].x();
qreal y2 = pts[3].y();
qreal bx1 = pts[1].x();
qreal by1 = pts[1].y();
qreal bx2 = pts[2].x();
qreal by2 = pts[2].y();
qreal qxa = x1*u0*u0 + bx1*2*t0*u0 + bx2*t0*t0;
qreal qxb = x1*u1*u1 + bx1*2*t1*u1 + bx2*t1*t1;
qreal qxc = bx1*u0*u0 + bx2*2*t0*u0 + x2*t0*t0;
qreal qxd = bx1*u1*u1 + bx2*2*t1*u1 + x2*t1*t1;
qreal qya = y1*u0*u0 + by1*2*t0*u0 + by2*t0*t0;
qreal qyb = y1*u1*u1 + by1*2*t1*u1 + by2*t1*t1;
qreal qyc = by1*u0*u0 + by2*2*t0*u0 + y2*t0*t0;
qreal qyd = by1*u1*u1 + by2*2*t1*u1 + y2*t1*t1;
ptsPart[0].setX(qxa*u0 + qxc*t0);
ptsPart[1].setX(qxa*u1 + qxc*t1);
ptsPart[2].setX(qxb*u0 + qxd*t0);
ptsPart[3].setX(qxb*u1 + qxd*t1);
ptsPart[0].setY(qya*u0 + qyc*t0);
ptsPart[1].setY(qya*u1 + qyc*t1);
ptsPart[2].setY(qyb*u0 + qyd*t0);
ptsPart[3].setY(qyb*u1 + qyd*t1);
}
void Widget::setPart(int idx, qreal val)
{
qreal& t = (idx == 0) ? t0 : t1;
t = val;
updatePart();
update();
}
int main(int argc, char* argv[])
{
QApplication app(argc, argv);
QWidget root;
QGridLayout* layout = new QGridLayout(&root);
layout->addWidget(new QLabel("t0:"), 0, 0);
layout->addWidget(new QLabel("t1:"), 1, 0);
QSlider* s0 = new QSlider(Qt::Horizontal);
QSlider* s1 = new QSlider(Qt::Horizontal);
layout->addWidget(s0, 0, 1);
layout->addWidget(s1, 1, 1);
s0->setRange(0, 100);
s1->setRange(0, 100);
Widget* widget = new Widget();
layout->addWidget(widget, 2, 0, 1, 2);
QObject::connect(s0, SIGNAL(valueChanged(int)), widget, SLOT(setT0(int)));
QObject::connect(s1, SIGNAL(valueChanged(int)), widget, SLOT(setT1(int)));
s0->setSliderPosition(20);
s1->setSliderPosition(75);
root.resize(800, 600);
root.setWindowTitle("Bezier part");
root.show();
return app.exec();
}
#include "main.moc" |
(
Сообщение от free334
