Qt环形颜色选择控件, 圆环颜色选择器

参考文章Qt编写自定义控件：环形颜色选择控件_qconicalgradient圆环渐变-CSDN博客

感谢作责提供的方法，下面程序的基础思路同参考文章。

为了更方便使用，这个选择器是基于64色表的，会显示选中的索引和色值。颜色选择时计算方式也有所不同。

选择器是逆时针的，先将64色填入渐变。通过根据小原型的位置，计算出角度，然后计算出它占360度的百分比，然后算出对应的索引，通过索引获得颜色，然后通知出去。

代码如下：

#include <QList>
#include <QColor>

const QList<QColor> listColor{
    QColor(0x72, 0x70, 0x1C),   //0
    QColor(0x6B, 0x72, 0x23),
    QColor(0x57, 0x76, 0x32),
    QColor(0x57, 0x6D, 0x3B),
    QColor(0x49, 0x61, 0x55),
    QColor(0x4B, 0x51, 0x63),
    QColor(0x46, 0x32, 0x87),
    QColor(0x3F, 0x12, 0xAE),   //7

    QColor(0x3F, 0x00, 0xC0),   //8
    QColor(0x5B, 0x0C, 0x98),
    QColor(0x68, 0x1D, 0x7A),
    QColor(0x7A, 0x36, 0x4F),
    QColor(0x8A, 0x20, 0x55),
    QColor(0x9C, 0x1E, 0x45),
    QColor(0xA7, 0x07, 0x51),
    QColor(0xB9, 0x13, 0x33),

    QColor(0xD1, 0x1E, 0x20),   //16
    QColor(0xC0, 0x2C, 0x13),
    QColor(0xDF, 0x13, 0x0D),
    QColor(0xFF, 0x00, 0x00),
    QColor(0xFD, 0x02, 0x00),
    QColor(0xFB, 0x02, 0x02),
    QColor(0xF1, 0x02, 0x0C),
    QColor(0xDB, 0x19, 0x0B),

    QColor(0xE4, 0x01, 0x1A),   //24
    QColor(0xC9, 0x06, 0x30),
    QColor(0x9D, 0x03, 0x5F),
    QColor(0x78, 0x06, 0x81),
    QColor(0x61, 0x04, 0x9A),
    QColor(0x48, 0x06, 0xB1),
    QColor(0x34, 0x03, 0xC8),
    QColor(0x2C, 0x05, 0xCF),

    QColor(0x24, 0x02, 0xD9),   //32
    QColor(0x00, 0x00, 0xFF),
    QColor(0x17, 0x01, 0xE7),
    QColor(0x1F, 0x01, 0xDF),
    QColor(0x20, 0x0F, 0xD0),
    QColor(0x30, 0x44, 0x8b),
    QColor(0x33, 0x78, 0x54),
    QColor(0x3A, 0x86, 0x3F),

    QColor(0x14, 0x82, 0x69),   //40
    QColor(0x18, 0x9B, 0x4C),
    QColor(0x0A, 0xBB, 0x3A),
    QColor(0x06, 0xE0, 0x19),
    QColor(0x1F, 0xC3, 0x1D),
    QColor(0x37, 0xB2, 0x16),
    QColor(0x1D, 0xDB, 0x08),
    QColor(0x00, 0xFF, 0x00),

    QColor(0x0F, 0xEE, 0x02),   //48
    QColor(0x34, 0xC9, 0x02),
    QColor(0x5D, 0xA0, 0x02),
    QColor(0x8D, 0x71, 0x01),
    QColor(0xA6, 0x58, 0x01),
    QColor(0xB9, 0x46, 0x00),
    QColor(0xD7, 0x28, 0x33),
    QColor(0xC9, 0x33, 0x03),
    
    QColor(0xDF, 0x1B, 0x05),   //56
    QColor(0xD5, 0x25, 0x05),
    QColor(0xC5, 0x35, 0x05),
    QColor(0xB0, 0x45, 0x0A),
    QColor(0x96, 0x5F, 0x0A),
    QColor(0x8A, 0x66, 0x0F),
    QColor(0x82, 0x6A, 0x13),
    QColor(0x7C, 0x6C, 0x18)    //63
};  //0-63(64色)

#ifndef COLORSELECTIONCIRCLE_H
#define COLORSELECTIONCIRCLE_H

#include <QWidget>

QT_BEGIN_NAMESPACE
namespace Ui { class ColorSelectionCircle; }
QT_END_NAMESPACE

class ColorSelectionCircle : public QWidget
{
    Q_OBJECT

public:
    ColorSelectionCircle(QWidget *parent = nullptr);
    ~ColorSelectionCircle();

protected:
    void paintEvent(QPaintEvent *event)override;
    void mousePressEvent(QMouseEvent *event)override;
    void mouseReleaseEvent(QMouseEvent *event)override;
    void mouseMoveEvent(QMouseEvent *event)override;
    void showEvent(QShowEvent *event) override;

signals:
    void ColorInfo(int index, QColor color);


private:
    qreal ballAngle{0};
    bool isPressed{false};
    void getColorInWidget(const QPoint &pos);
    QColor selectColor;//
   
    int m_index{0};

private:
    Ui::ColorSelectionCircle *ui;
};
#endif // COLORSELECTIONCIRCLE_H

#include "colorselectioncircle.h"
#include "ui_colorselectioncircle.h"
#include <QPaintEvent>
#include <QPainterPath>
#include <QDebug>
#include <QtMath>
#include <QGuiApplication>
#include <QScreen>
#include <QPainter>
#include "commondata.h"

ColorSelectionCircle::ColorSelectionCircle(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::ColorSelectionCircle)
{
    ui->setupUi(this);
    setPalette(Qt::white);
    setMinimumSize(150, 150);


}

ColorSelectionCircle::~ColorSelectionCircle()
{
    delete ui;
}

void ColorSelectionCircle::mousePressEvent(QMouseEvent *event)
{
    if (event->button() == Qt::LeftButton)
    {
        auto pressPos = event->pos();
        QPoint centerPoint = rect().center();
        
        ballAngle = -atan2(pressPos.y() - centerPoint.y(), pressPos.x() - centerPoint.x()) * (180 / M_PI);
        
        if(ballAngle < 0)
        {
            ballAngle = ballAngle + 360;
        }

        auto tmpballAngle = ((int)(ballAngle + 360.0 / listColor.size() / 2)) % 360 ;
        m_index = tmpballAngle / 360.0 * listColor.size();
        
        isPressed = true;
        emit ColorInfo(m_index, listColor[m_index]);
        update();
    }
    QWidget::mousePressEvent(event);
}

void ColorSelectionCircle::mouseReleaseEvent(QMouseEvent *event)
{
    if (isPressed)
    {
        isPressed = false;
    }
    return QWidget::mouseReleaseEvent(event);
}

void ColorSelectionCircle::mouseMoveEvent(QMouseEvent* event)
{
    if (isPressed)
    {
        auto nowPos = event->pos();
        QPoint centerPoint = rect().center();
        ballAngle = -atan2(nowPos.y() - centerPoint.y(), nowPos.x() - centerPoint.x()) * (180 / M_PI);
        //qDebug()<<"ballAngle:"<<ballAngle;
        if(ballAngle < 0)
        {
            ballAngle = ballAngle + 360;
        }
        auto tmpballAngle = ((int)(ballAngle + 360.0 / listColor.size() / 2))%360 ;
        

        //qDebug()<<"ballAngle after:"<<tmpballAngle;
        
        m_index = tmpballAngle / 360.0 * listColor.size();

        emit ColorInfo(m_index, listColor[m_index]);
        update();
    }
    return QWidget::mouseMoveEvent(event);
}

void ColorSelectionCircle::showEvent(QShowEvent *event)
{
    emit ColorInfo(m_index, listColor[m_index]);
    update();
    return QWidget::showEvent(event);
}

void ColorSelectionCircle::getColorInWidget(const QPoint &pos)
{
    static QScreen *screen = QGuiApplication::screenAt(pos);
    if (!screen)
    {
        screen = QGuiApplication::primaryScreen();
    }
    auto gpos = mapToGlobal(pos);
    selectColor = screen->grabWindow(0, gpos.x(), gpos.y(), 1, 1).toImage().pixel(0, 0);
}

void ColorSelectionCircle::paintEvent(QPaintEvent *event)
{
    QPainter painter(this);
    painter.setRenderHint(QPainter::Antialiasing);
    painter.setPen(Qt::transparent);

    auto rect = event->rect();
    auto standardLength = std::min(rect.width(), rect.height());
    auto radius = standardLength / 2 - standardLength * 0.1;
    QConicalGradient conicalGradient(0, 0, 0);


    for (int i=0; i<listColor.size(); ++i)
    {
        auto pos = 1.0 * i / listColor.size();
        
        conicalGradient.setColorAt(pos, listColor[i]);
    }
    conicalGradient.setColorAt(1.0, listColor[0]);
    painter.translate(rect.center());

    QBrush brush(conicalGradient);
    painter.setPen(Qt::NoPen);
    painter.setBrush(brush);

    QPainterPath path1;
    path1.addEllipse(QPoint(0, 0), radius, radius);

    QPainterPath path2;
    path2.addEllipse(QPoint(0, 0), radius * 0.8, radius* 0.8);
    painter.drawPath(path1- path2);

    QPointF ballPos = QPointF(cos(ballAngle * M_PI/180)*radius*0.9, -sin(ballAngle*M_PI/180)*radius*0.9);
    painter.setPen(QColor(0xff, 0xff, 0xff));
    painter.drawEllipse(ballPos, radius*0.2, radius*0.2);
    painter.setBrush(listColor[m_index]);

}

#include "colorselect.h"
#include "ui_colorselect.h"
#include <QPalette>

ColorSelect::ColorSelect(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::ColorSelect)
{
    ui->setupUi(this);
    this->setWindowTitle(QString("Color Selector"));
    connect(ui->widget, SIGNAL(ColorInfo(int,QColor)), this, SLOT(ColorInfoProcess(int,QColor)));
}

ColorSelect::~ColorSelect()
{
    delete ui;
}

void ColorSelect::ColorInfoProcess(int index, QColor color)
{
    ui->lineEdit_index->setText(QString("%1").arg(index));
    ui->lineEdit_RGB->setText(color.name());
    QPalette pe;

    pe.setColor(ui->label_color->backgroundRole(), color);
    ui->label_color->setAutoFillBackground(true);
    ui->label_color->setPalette(pe);
}