Program Listing for File colorwheel.h

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/*
    NanoGUI was developed by Wenzel Jakob <wenzel.jakob@epfl.ch>.
    The widget drawing code is based on the NanoVG demo application
    by Mikko Mononen.

    All rights reserved. Use of this source code is governed by a
    BSD-style license that can be found in the LICENSE.txt file.
*/
#pragma once

#include <nanogui/widget.h>

NAMESPACE_BEGIN(nanogui)


class NANOGUI_EXPORT ColorWheel : public Widget {
public:
    ColorWheel(Widget *parent, const Color& color = Color(1.0f, 0.0f, 0.0f, 1.0f));

    std::function<void(const Color &)> callback() const { return mCallback; }

    void setCallback(const std::function<void(const Color &)> &callback) { mCallback = callback; }

    Color color() const;

    void setColor(const Color& color);

    virtual Vector2i preferredSize(NVGcontext *ctx) const override;

    virtual void draw(NVGcontext *ctx) override;

    virtual bool mouseButtonEvent(const Vector2i &p, int button, bool down, int modifiers) override;

    virtual bool mouseDragEvent(const Vector2i &p, const Vector2i &rel, int button, int modifiers) override;

    virtual void save(Serializer &s) const override;

    virtual bool load(Serializer &s) override;

private:
    // Used to describe where the mouse is interacting
    enum Region {
        None = 0,
        InnerTriangle = 1,
        OuterCircle = 2,
        Both = 3
    };

    // Converts a specified hue (with saturation = value = 1) to RGB space.
    Color hue2rgb(float h) const;

    // Manipulates the positioning of the different regions of the ColorWheel.
    Region adjustPosition(const Vector2i &p, Region consideredRegions = Both);

protected:
    float mHue;

    float mWhite;

    float mBlack;

    Region mDragRegion;

    std::function<void(const Color &)> mCallback;

public:
    EIGEN_MAKE_ALIGNED_OPERATOR_NEW
};

NAMESPACE_END(nanogui)