QtCurvesCpp/renderarea.cpp

#include "renderarea.h"
#include <QPainter>

QSize RenderArea::minimumSizeHint() const
{
	return QSize{491,481};
}

QSize RenderArea::sizeHint() const
{
	return QSize{491,481};
}

void RenderArea::paintEvent(QPaintEvent* event)
{
	Q_UNUSED(event);
	QPainter painter{this};
	painter.setRenderHint(QPainter::Antialiasing,true);

	painter.setBrush(mBackgroundColour);
	painter.setPen(mShapeColour);

	painter.drawRect(this->rect());

	QPointF prevPoint{Compute(0)};
	QPoint center{this->rect().center()},prevPixel;
	prevPixel.setX(prevPoint.x() * mScale + center.x());
	prevPixel.setY(prevPoint.y() * mScale + center.y());

	double step{ mIntervalLenght / mStepCount };

	for(double t{0}; t < mIntervalLenght; t += step){
		QPointF point = Compute(t);

		QPoint pixel{};
		pixel.setX(point.x() * mScale + center.x());
		pixel.setY(point.y() * mScale + center.y());

		painter.drawLine(pixel, prevPixel);

		prevPixel=pixel;
	}
	QPointF point = Compute(mIntervalLenght);
	QPoint pixel{};
	pixel.setX(point.x() * mScale + center.x());
	pixel.setY(point.y() * mScale + center.y());
	painter.drawLine(pixel, prevPixel);
}

RenderArea::RenderArea(QWidget *parent) :
	QWidget{parent},
	mBackgroundColour{36,35,35},
	mShapeColour{251,250,250},
	mShape{Astroid}
{
	OnShapeChanged();
}

QPointF RenderArea::ComputeAstroid(double t){
	return QPointF{
		2*pow(cos(t),3),
				2*pow(sin(t),3)
	};
}

QPointF RenderArea::ComputeCycloid(double t)
{
	return QPointF{
		1.5 * (1 - cos(t)),
				1.5 * (t - sin(t))
	};
}

QPointF RenderArea::ComputeHuygens(double t)
{
	return QPointF{
		4 * (3 * cos(t) - cos(3 * t)),
				4 * (3 * sin(t) - sin(3 * t))
	};
}

QPointF RenderArea::ComputeHypo(double t)
{
	return QPointF{
		1.5 * (2 * cos(t) + cos(2 * t)),
				1.5 * (2 * sin(t) - sin(2 * t))
	};
}

QPointF RenderArea::ComputeLine(double t)
{
	return QPointF{1-t,1-t};
}

QPointF RenderArea::ComputeCircle(double t)
{
	return QPointF{cos(t),sin(t)};
}

QPointF RenderArea::ComputeEllipse(double t)
{
	double a{2},b{1.1};
	return QPointF{a*cos(t),b*sin(t)};
}

QPointF RenderArea::ComputeFancy(double t)
{
	return QPointF{
		11*cos(t) - 6*cos((11.0/6)*t),
				11*sin(t) - 6*sin((11.0/6)*t)
	};
}

QPointF RenderArea::ComputeStarfish(double t)
{
	double R{5},r{3},d{5};
	return QPointF{
		(R-r)*cos(t) + d*cos(t*((R-r)/r)),
				(R-r)*sin(t) - d*sin(t*((R-r)/r))
	};
}

void RenderArea::OnShapeChanged()
{
	switch (mShape) {
		case Astroid:
			mScale=90;
			mIntervalLenght=2*M_PI;
			mStepCount=512;
		break;
		case Cycloid:
			mScale=10;
			mIntervalLenght=4*M_PI;
			mStepCount=128;
		break;
		case HuygensCycloid:
			mScale=10;
			mIntervalLenght=4*M_PI;
			mStepCount=512;
		break;
		case HypoCycloid:
			mScale=40;
			mIntervalLenght=2*M_PI;
			mStepCount=256;
		break;
		case Line:
			mScale=100;
			mIntervalLenght=2;
			mStepCount=128;
		break;
		case Circle:
			mScale=100;
			mIntervalLenght=2*M_PI;
			mStepCount=128;
		break;
		case Ellipse:
			mScale=75;
			mIntervalLenght=2*M_PI;
			mStepCount=256;
		break;
		case Fancy:
			mScale=10;
			mIntervalLenght=12*M_PI;
			mStepCount=512;
		break;
		case Starfish:
			mScale=25;
			mIntervalLenght=6*M_PI;
			mStepCount=256;
		break;
		default:
		break;
	}
}

QPointF RenderArea::Compute(double t)
{
	switch (mShape) {
		case Astroid:
			return ComputeAstroid(t);
		break;
		case Cycloid:
			return ComputeCycloid(t);
		break;
		case HuygensCycloid:
			return ComputeHuygens(t);
		break;
		case HypoCycloid:
			return ComputeHypo(t);
		break;
		case Line:
			return ComputeLine(t);
		break;
		case Circle:
			return ComputeCircle(t);
		break;
		case Ellipse:
			return ComputeEllipse(t);
		break;
		case Fancy:
			return ComputeFancy(t);
		break;
		case Starfish:
			return ComputeStarfish(t);
		break;
		default:
		break;
	}
	return QPointF{0,0};
}