159 lines
4.0 KiB
C++
159 lines
4.0 KiB
C++
// Copyright Vladimir Prus 2005.
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt
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// or copy at http://www.boost.org/LICENSE_1_0.txt)
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#include "arrow.h"
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#include <QtGui/qapplication.h>
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#include <QtGui/qwidget.h>
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#include <QtGui/qpainter.h>
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#include <QtGui/qpainterpath.h>
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#include <stdlib.h>
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#include <math.h>
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Arrow_widget::Arrow_widget(QWidget* parent) : QWidget(parent), color_(0)
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{
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QPalette pal = palette();
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pal.setBrush(backgroundRole(), QBrush(Qt::white));
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setPalette(pal);
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}
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void Arrow_widget::slotChangeColor()
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{
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color_ = (color_ + 1) % 3;
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update();
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}
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void
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Arrow_widget::draw_arrow(int x1, int y1, int x2, int y2, QPainter& painter)
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{
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// The length of the from the tip of the arrow to the point
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// where line starts.
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const int arrowhead_length = 16;
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QPainterPath arrow;
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arrow.moveTo(x1, y1);
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// Determine the angle of the straight line.
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double a1 = (x2-x1);
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double a2 = (y2-y1);
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double b1 = 1;
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double b2 = 0;
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double straight_length = sqrt(a1*a1 + a2*a2);
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double dot_product = a1*b1 + a2*b2;
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double cosine = dot_product/
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(sqrt(pow(a1, 2) + pow(a2, 2))*sqrt(b1 + b2));
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double angle = acos(cosine);
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if (y1 < y2)
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{
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angle = -angle;
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}
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double straight_angle = angle*180/M_PI;
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double limit = 10;
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double angle_to_vertical;
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if (fabs(straight_angle) < 90)
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angle_to_vertical = fabs(straight_angle);
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else if (straight_angle > 0)
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angle_to_vertical = 180-straight_angle;
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else
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angle_to_vertical = 180-(-straight_angle);
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double angle_delta = 0;
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if (angle_to_vertical > limit)
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angle_delta = 30 * (angle_to_vertical - limit)/90;
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double start_angle = straight_angle > 0
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? straight_angle - angle_delta :
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straight_angle + angle_delta;
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QMatrix m1;
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m1.translate(x1, y1);
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m1.rotate(-start_angle);
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double end_angle = straight_angle > 0
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? (straight_angle + 180 + angle_delta) :
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(straight_angle + 180 - angle_delta);
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QMatrix m2;
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m2.reset();
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m2.translate(x2, y2);
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m2.rotate(-end_angle);
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arrow.cubicTo(m1.map(QPointF(straight_length/2, 0)),
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m2.map(QPointF(straight_length/2, 0)),
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m2.map(QPointF(arrowhead_length, 0)));
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painter.save();
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painter.setBrush(Qt::NoBrush);
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painter.drawPath(arrow);
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painter.restore();
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painter.save();
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painter.translate(x2, y2);
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painter.rotate(-90);
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painter.rotate(-end_angle);
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painter.rotate(180);
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QPolygon arrowhead(4);
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arrowhead.setPoint(0, 0, 0);
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arrowhead.setPoint(1, arrowhead_length/3, -arrowhead_length*5/4);
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arrowhead.setPoint(2, 0, -arrowhead_length);
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arrowhead.setPoint(3, -arrowhead_length/3, -arrowhead_length*5/4);
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painter.drawPolygon(arrowhead);
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painter.restore();
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}
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void Arrow_widget::paintEvent(QPaintEvent*)
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{
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QPainter p(this);
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p.setRenderHint(QPainter::Antialiasing);
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int base_x = 550;
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int base_y = 200;
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if (color_ == 0)
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p.setBrush(Qt::black);
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else if (color_ == 1)
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p.setBrush(Qt::green);
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else if (color_ == 2)
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p.setBrush(Qt::yellow);
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else
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p.setBrush(Qt::black);
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for (int x_step = 0; x_step < 6; ++x_step)
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{
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for (int y_step = 1; y_step <= 3; ++y_step)
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{
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draw_arrow(base_x, base_y, base_x+x_step*100,
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base_y - y_step*50, p);
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draw_arrow(base_x, base_y, base_x+x_step*100,
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base_y + y_step*50, p);
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draw_arrow(base_x, base_y, base_x-x_step*100,
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base_y + y_step*50, p);
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draw_arrow(base_x, base_y, base_x-x_step*100,
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base_y - y_step*50, p);
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}
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}
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draw_arrow(50, 400, 1000, 450, p);
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draw_arrow(1000, 400, 50, 450, p);
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}
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