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shape.cpp
194 lines (163 loc) · 4.27 KB
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shape.cpp
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#include <QLineF>
#include "shape.h"
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Helpers
double segmentLenght(QPointF a, QPointF b)
{
return QLineF(a, b).length();
}
void assertPolygonIsClosed(QPolygonF polygon)
{
ASSERT_RETURN(polygon.isEmpty() || polygon.first() == polygon.last());
}
bool testSegmentsCross(QPointF a, QPointF b, QPointF c, QPointF d)
{
return QLineF(a, b).intersect(QLineF(c, d), 0) == QLineF::BoundedIntersection;
}
bool isSelfintersectingPolygon(QPolygonF polygon)
{
assertPolygonIsClosed(polygon);
int n = polygon.size() - 1; // cut off last vertex
for (int i1 = 0; i1 < n; i1++) {
int i2 = (i1 + 1) % n;
for (int j1 = 0; j1 < n; j1++) {
int j2 = (j1 + 1) % n;
if (i1 != j1 && i1 != j2 && i2 != j1
&& testSegmentsCross(polygon[i1], polygon[i2], polygon[j1], polygon[j2]))
return true;
}
}
return false;
}
double triangleSignedArea(QPointF a, QPointF b, QPointF c)
{
QPointF p = b - a;
QPointF q = c - a;
return (p.x() * q.y() - p.y() * q.x()) / 2.0;
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Shape
Shape::Shape(ShapeType shapeType) :
vertices_(),
type_(shapeType),
isFinished_(false)
{
}
bool Shape::addPoint(QPointF newPoint)
{
ASSERT_RETURN_V(!isFinished_, true);
if (!vertices_.isEmpty() && newPoint == vertices_.back())
return false;
vertices_.append(newPoint);
switch (type_) {
case SEGMENT:
case RECTANGLE:
ASSERT_RETURN_V(vertices_.size() <= 2, true);
isFinished_ = (vertices_.size() == 2);
return isFinished_;
case POLYLINE:
case CLOSED_POLYLINE:
case POLYGON:
return false;
}
ERROR_RETURN_V(true);
}
void Shape::finish()
{
ASSERT_RETURN(!vertices_.empty());
isFinished_ = true;
}
void Shape::scale(double factor)
{
for (int i = 0; i < vertices_.size(); ++i)
vertices_[i] *= factor;
}
void Shape::dragVertex(int iVertex, QPointF newPos)
{
switch (type_) {
case SEGMENT:
case POLYLINE:
case CLOSED_POLYLINE:
case POLYGON:
vertices_[iVertex] = newPos;
break;
case RECTANGLE:
ASSERT_RETURN(vertices_.size() == 2);
switch (iVertex) {
case 0: vertices_[0] = newPos; break;
case 1: vertices_[0].ry() = newPos.y(); vertices_[1].rx() = newPos.x(); break;
case 2: vertices_[1] = newPos; break;
case 3: vertices_[0].rx() = newPos.x(); vertices_[1].ry() = newPos.y(); break;
default: ERROR_RETURN();
}
break;
}
}
QPolygonF Shape::vertices() const
{
QPolygonF result = vertices_;
switch (type_) {
case SEGMENT:
case POLYLINE:
case CLOSED_POLYLINE:
case POLYGON:
break;
case RECTANGLE:
if (result.size() == 2) {
result = QPolygonF(QRectF(result[0], result[1]));
result.pop_back();
}
break;
}
return result;
}
QPolygonF Shape::polygon() const
{
QPolygonF result = vertices_;
switch (type_) {
case SEGMENT:
case POLYLINE:
break;
case CLOSED_POLYLINE:
case POLYGON:
result.append(result.first());
break;
case RECTANGLE:
if (result.size() == 2)
result = QPolygonF(QRectF(result[0], result[1]));
break;
}
return result;
}
ShapeCorrectness Shape::correctness() const
{
switch (type_) {
case SEGMENT:
case POLYLINE:
case CLOSED_POLYLINE:
case RECTANGLE:
return VALID_SHAPE;
case POLYGON:
return isSelfintersectingPolygon(polygon()) ? SELF_INTERSECTING_POLYGON : VALID_SHAPE;
}
ERROR_RETURN_V(VALID_SHAPE);
}
double Shape::length() const
{
ASSERT_RETURN_V(dimensionality() == SHAPE_1D, 0.);
QPolygonF p = polygon();
double result = 0.;
for (int i = 0; i < p.size() - 1; i++)
result += segmentLenght(p[i], p[i + 1]);
return result;
}
double Shape::area() const
{
ASSERT_RETURN_V(dimensionality() == SHAPE_2D, 0.);
QPolygonF p = polygon();
assertPolygonIsClosed(p);
double result = 0.;
for (int i = 1; i < p.size() - 2; i++)
result += triangleSignedArea(p[0], p[i], p[i + 1]);
return qAbs(result);
}