fractorium/Source/Fractorium/PaletteEditor/ColorTriangle.h

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#pragma once

#include "FractoriumPch.h"

/// <summary>
/// DoubleColor, Vertex and ColorTriangle classes.
/// </summary>

/// <summary>
/// Used to store color values in the range 0..255 as doubles.
/// </summary>
struct DoubleColor
{
	double r, g, b;

	DoubleColor() : r(0.0), g(0.0), b(0.0) {}
	DoubleColor(double red, double green, double blue) : r(red), g(green), b(blue) {}
	DoubleColor(const DoubleColor& c) : r(c.r), g(c.g), b(c.b) {}
};

/// <summary>
/// Used to store pairs of DoubleColor and DoublePoint in one structure.
/// </summary>
struct Vertex
{
	DoubleColor color;
	QPointF point;

	Vertex(const DoubleColor& c, const QPointF& p) : color(c), point(p) {}
	Vertex(const QColor& c, const QPointF& p)
		: color(DoubleColor(static_cast<double>(c.red()), static_cast<double>(c.green()),
							static_cast<double>(c.blue()))), point(p) {}
};

/// <summary>
/// Widget for drawing a color triangle which allows users to select colors
/// in a manner more intuitive than the usual color picker dialog.
/// This class was taken from an open source project named Chaos Helper, which took
/// it from the Qt examples, so it mostly remains as-is.
/// </summary>
class ColorTriangle : public QWidget
{
	Q_OBJECT

public:
	ColorTriangle(QWidget* parent = nullptr);

	void Polish();
	QColor Color() const;
	void Color(const QColor& col);

	int heightForWidth(int w) const override;
	QSize sizeHint() const override;

Q_SIGNALS:
	void ColorChanged(const QColor& col);

protected:
	void paintEvent(QPaintEvent*) override;
	void mouseMoveEvent(QMouseEvent*) override;
	void mousePressEvent(QMouseEvent*) override;
	void mouseReleaseEvent(QMouseEvent*) override;
	void keyPressEvent(QKeyEvent* e) override;
	void resizeEvent(QResizeEvent*) override;

private:
	void GenBackground();
	void DrawTrigon(QImage* p, const QPointF& a, const QPointF& b, const QPointF& c, const QColor& color);
	double CalcOuterRadius() const;
	double RadiusAt(const QPointF& pos, const QRect& rect) const;
	double AngleAt(const QPointF& pos, const QRect& rect) const;
	QColor ColorFromPoint(const QPointF& p) const;
	QPointF PointFromColor(const QColor& col) const;
	QPointF MovePointToTriangle(double x, double y, const Vertex& a, const Vertex& b, const Vertex& c) const;

	bool mustGenerateBackground;
	int curHue;
	int penWidth;
	int ellipseSize;
	int outerRadius;
	double a, b, c;
	QImage bg;
	QColor curColor;
	QPointF pa, pb, pc, pd;
	QPointF selectorPos;

	enum SelectionMode
	{
		Idle,
		SelectingHue,
		SelectingSatValue
	} selMode;
};