qml刷新C++中的QImage图像

第一步：重写QQuickImageProvider类

#include <QQuickImageProvider>class CQuickImagePainter : public QQuickImageProvider
{
public:CQuickImagePainter();QImage requestImage(const QString&id,   QSize *, const QSize &);QPixmap requestPixmap(const QString&id, QSize *, const QSize &);public:QImage img;
};

#include "CQuickImagePainter.h"CQuickImagePainter::CQuickImagePainter(): QQuickImageProvider(QQuickImageProvider::Image)
{}QImage CQuickImagePainter::requestImage(const QString&id, QSize*, const QSize&)
{return this->img;
}QPixmap CQuickImagePainter::requestPixmap(const QString&id, QSize*, const QSize&)
{return QPixmap::fromImage(this->img);
}

第二步：定义刷新图像的类

#include <QObject>
#include <CQuickImagePainter.h>class CQuickImageRefresh : public QObject
{Q_OBJECT
public:explicit CQuickImageRefresh(QObject *parent = nullptr);CQuickImagePainter*m_RePainter;signals:void reDrawImage();public slots:void setImage(QImage image);
};

#include "CQuickImageRefresh.h"CQuickImageRefresh::CQuickImageRefresh(QObject *parent) : QObject(parent)
{m_RePainter = new CQuickImagePainter;
}void CQuickImageRefresh::setImage(QImage image)
{m_RePainter->img = image;emit reDrawImage();
}

第三步：关联qml

#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QQmlContext>
#include "CQuickImageRefresh.h"//设置为全局变量-可以在线程中更新图像
CQuickImageRefresh *CodeImage1 = new CQuickImageRefresh();
int main(int argc, char *argv[])
{QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);QGuiApplication app(argc, argv);QQmlApplicationEngine engine;const QUrl url(QStringLiteral("qrc:/main.qml"));QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,&app, [url](QObject *obj, const QUrl &objUrl) {if (!obj && url == objUrl)QCoreApplication::exit(-1);}, Qt::QueuedConnection);engine.load(url);//管理qmlengine.rootContext()->setContextProperty("CodeImage1",CodeImage1);engine.addImageProvider(QLatin1String("CodeImg1"), CodeImage1->m_RePainter);//每次CodeImage1->setImage(image)的时候界面自动刷新QImage image = QImage(data,width,height,QImage::Format_RGB888);CodeImage1->setImage(image);return app.exec();
}

第四步：qml显示

import QtQuick 2.12
import QtQuick.Window 2.12
import QtQuick.Controls 2.12Window {width: 640height: 320visible: truetitle: qsTr("Hello World")Image{id:img1width: 640height: 360x:0y:0}Connections{target: CodeImage1onReDrawImage:{img1.source = ""img1.source = "image://CodeImg1"}}
}