前文链接：QGraphicsView实现简易地图16『爆炸效果』
模仿水波荡漾时的涟漪效果，参考了echarts中的散点图
支持设置散点大小、颜色、涟漪线条宽度。
动态演示效果

静态展示图片

核心代码

#pragma once
#include "../AbstractGeoItem.h"
#include "DataStruct/GeoData.h"

/*
 * 散点效果-静态
 */

class EffectScatterItem : public AbstractGeoItem
{
public:
	explicit EffectScatterItem(const GeoCoord &geoCoord, int radius, QGraphicsItem *parent = nullptr);
	~EffectScatterItem();

	// 设置百分比（值：0-1）
	void setPercent(double percent);
	// 获取百分比
	double percent();
	// 设置颜色
	void setColor(QColor color);
	// 设置涟漪线宽
	void setRippleWidth(double width);

protected:
	virtual QRectF boundingRect() const override;
	virtual void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget) override;

private:
	int m_radius;			// 半径（单位：像素）
	double m_percent;		// 每条涟漪扩散百分比
	double m_ripplesWidth;	// 涟漪线宽
	QColor m_color;			// 颜色
};

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

EffectScatterItem::EffectScatterItem(const GeoCoord &geoCoord, int radius, QGraphicsItem *parent /*= nullptr*/)
	: AbstractGeoItem(parent)
{
	setZValue(302);
	setGeoPos(geoCoord.lon, geoCoord.lat);
	m_radius = radius;
	m_percent = 0;
	m_ripplesWidth = 1.5;
	m_color = Qt::white;
}

EffectScatterItem::~EffectScatterItem()
{

}

void EffectScatterItem::setPercent(double percent)
{
	m_percent = percent;
	update();
}

double EffectScatterItem::percent()
{
	return m_percent;
}

void EffectScatterItem::setColor(QColor color)
{
	m_color = color;
	update();
}

void EffectScatterItem::setRippleWidth(double width)
{
	m_ripplesWidth = width;
	update();
}

QRectF EffectScatterItem::boundingRect() const
{
	return QRectF(-m_radius, -m_radius, 2 * m_radius, 2 * m_radius);
}

void EffectScatterItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
	painter->setPen(Qt::NoPen);
	painter->setBrush(m_color);
	painter->setRenderHint(QPainter::Antialiasing);
	painter->drawEllipse(QPointF(0, 0), m_radius * 0.4, m_radius * 0.4);

	painter->setBrush(Qt::NoBrush);

	for (int i = 1; i <= 3; ++i)
	{
		QColor color = m_color;
		color.setAlphaF((4 - i - m_percent) / 3);
		painter->setPen(QPen(color, m_ripplesWidth));
		
		double radius = m_radius * (0.4 + (i - 1 + m_percent) * 0.2);
		painter->drawEllipse(QPointF(0, 0), radius, radius);
	}
}