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),   //0QColor(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),   //7QColor(0x3F, 0x00, 0xC0),   //8QColor(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),   //16QColor(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),   //24QColor(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),   //32QColor(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),   //40QColor(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),   //48QColor(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),   //56QColor(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_NAMESPACEclass ColorSelectionCircle : public QWidget
{Q_OBJECTpublic: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);
}