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1 | // Copyright Vladimir Prus 2005. |
2 | // Distributed under the Boost Software License, Version 1.0. | |
3 | // (See accompanying file LICENSE_1_0.txt | |
4 | // or copy at http://www.boost.org/LICENSE_1_0.txt) | |
5 | ||
6 | #include "arrow.h" | |
7 | ||
8 | #include <QtGui/qapplication.h> | |
9 | ||
10 | #include <QtGui/qwidget.h> | |
11 | #include <QtGui/qpainter.h> | |
12 | #include <QtGui/qpainterpath.h> | |
13 | ||
14 | #include <stdlib.h> | |
15 | #include <math.h> | |
16 | ||
17 | Arrow_widget::Arrow_widget(QWidget* parent) : QWidget(parent), color_(0) | |
18 | { | |
19 | QPalette pal = palette(); | |
20 | pal.setBrush(backgroundRole(), QBrush(Qt::white)); | |
21 | setPalette(pal); | |
22 | } | |
23 | ||
24 | void Arrow_widget::slotChangeColor() | |
25 | { | |
26 | color_ = (color_ + 1) % 3; | |
27 | update(); | |
28 | } | |
29 | ||
30 | void | |
31 | Arrow_widget::draw_arrow(int x1, int y1, int x2, int y2, QPainter& painter) | |
32 | { | |
33 | // The length of the from the tip of the arrow to the point | |
34 | // where line starts. | |
35 | const int arrowhead_length = 16; | |
36 | ||
37 | QPainterPath arrow; | |
38 | arrow.moveTo(x1, y1); | |
39 | ||
40 | // Determine the angle of the straight line. | |
41 | double a1 = (x2-x1); | |
42 | double a2 = (y2-y1); | |
43 | double b1 = 1; | |
44 | double b2 = 0; | |
45 | ||
46 | double straight_length = sqrt(a1*a1 + a2*a2); | |
47 | ||
48 | double dot_product = a1*b1 + a2*b2; | |
49 | double cosine = dot_product/ | |
50 | (sqrt(pow(a1, 2) + pow(a2, 2))*sqrt(b1 + b2)); | |
51 | double angle = acos(cosine); | |
52 | if (y1 < y2) | |
53 | { | |
54 | angle = -angle; | |
55 | } | |
56 | double straight_angle = angle*180/M_PI; | |
57 | ||
58 | double limit = 10; | |
59 | ||
60 | double angle_to_vertical; | |
61 | if (fabs(straight_angle) < 90) | |
62 | angle_to_vertical = fabs(straight_angle); | |
63 | else if (straight_angle > 0) | |
64 | angle_to_vertical = 180-straight_angle; | |
65 | else | |
66 | angle_to_vertical = 180-(-straight_angle); | |
67 | ||
68 | double angle_delta = 0; | |
69 | if (angle_to_vertical > limit) | |
70 | angle_delta = 30 * (angle_to_vertical - limit)/90; | |
71 | double start_angle = straight_angle > 0 | |
72 | ? straight_angle - angle_delta : | |
73 | straight_angle + angle_delta; | |
74 | ||
75 | ||
76 | QMatrix m1; | |
77 | m1.translate(x1, y1); | |
78 | m1.rotate(-start_angle); | |
79 | ||
80 | double end_angle = straight_angle > 0 | |
81 | ? (straight_angle + 180 + angle_delta) : | |
82 | (straight_angle + 180 - angle_delta); | |
83 | ||
84 | QMatrix m2; | |
85 | m2.reset(); | |
86 | m2.translate(x2, y2); | |
87 | m2.rotate(-end_angle); | |
88 | ||
89 | arrow.cubicTo(m1.map(QPointF(straight_length/2, 0)), | |
90 | m2.map(QPointF(straight_length/2, 0)), | |
91 | m2.map(QPointF(arrowhead_length, 0))); | |
92 | ||
93 | painter.save(); | |
94 | painter.setBrush(Qt::NoBrush); | |
95 | painter.drawPath(arrow); | |
96 | painter.restore(); | |
97 | ||
98 | painter.save(); | |
99 | painter.translate(x2, y2); | |
100 | ||
101 | painter.rotate(-90); | |
102 | painter.rotate(-end_angle); | |
103 | painter.rotate(180); | |
104 | ||
105 | QPolygon arrowhead(4); | |
106 | arrowhead.setPoint(0, 0, 0); | |
107 | arrowhead.setPoint(1, arrowhead_length/3, -arrowhead_length*5/4); | |
108 | arrowhead.setPoint(2, 0, -arrowhead_length); | |
109 | arrowhead.setPoint(3, -arrowhead_length/3, -arrowhead_length*5/4); | |
110 | ||
111 | painter.drawPolygon(arrowhead); | |
112 | ||
113 | painter.restore(); | |
114 | ||
115 | } | |
116 | ||
117 | ||
118 | void Arrow_widget::paintEvent(QPaintEvent*) | |
119 | { | |
120 | QPainter p(this); | |
121 | ||
122 | p.setRenderHint(QPainter::Antialiasing); | |
123 | ||
124 | int base_x = 550; | |
125 | int base_y = 200; | |
126 | ||
127 | if (color_ == 0) | |
128 | p.setBrush(Qt::black); | |
129 | else if (color_ == 1) | |
130 | p.setBrush(Qt::green); | |
131 | else if (color_ == 2) | |
132 | p.setBrush(Qt::yellow); | |
133 | else | |
134 | p.setBrush(Qt::black); | |
135 | ||
136 | for (int x_step = 0; x_step < 6; ++x_step) | |
137 | { | |
138 | for (int y_step = 1; y_step <= 3; ++y_step) | |
139 | { | |
140 | draw_arrow(base_x, base_y, base_x+x_step*100, | |
141 | base_y - y_step*50, p); | |
142 | ||
143 | draw_arrow(base_x, base_y, base_x+x_step*100, | |
144 | base_y + y_step*50, p); | |
145 | ||
146 | draw_arrow(base_x, base_y, base_x-x_step*100, | |
147 | base_y + y_step*50, p); | |
148 | ||
149 | draw_arrow(base_x, base_y, base_x-x_step*100, | |
150 | base_y - y_step*50, p); | |
151 | } | |
152 | } | |
153 | ||
154 | draw_arrow(50, 400, 1000, 450, p); | |
155 | draw_arrow(1000, 400, 50, 450, p); | |
156 | ||
157 | } | |
158 |