QSharedMemory QBuffer QDataStream 共享内存传输图片 基本控件（十八）

一、效果图

二、代码

#include "sharedmenory.h"
#include <QSharedMemory>
#include <QPixmap>
#include <QCoreApplication>
#include <QDir>
#include <QBuffer>
#include <QDataStream>
#include <QDebug>
sharedMenory::sharedMenory()
{
    create();
    read();
}

void sharedMenory::create()
{
    QPixmap pixmap;
    pixmap.load(QCoreApplication::applicationDirPath() + QDir::separator() + "1.jpg");

    QBuffer buffer;
    buffer.open(QIODevice::ReadWrite);

    QDataStream out(&buffer);
    out<<pixmap;

    int buffer_size = buffer.size();

    QSharedMemory *pSharedMen = new QSharedMemory("key-img",this);
    bool ret = pSharedMen->create(buffer_size);
    int shareMen_size = pSharedMen->size();

    if(!ret){
        qDebug()<<pSharedMen->errorString();
        return;
    }

    pSharedMen->lock();
    char* to = static_cast<char*>(pSharedMen->data());
    const char* from = buffer.data().constData();
    memcpy(to,from,qMin(buffer_size,shareMen_size));
    pSharedMen->unlock();
}

void sharedMenory::read()
{
    QBuffer buffer;
    QDataStream in(&buffer);
    QPixmap pixmap;

    QSharedMemory *pSharedMen = new QSharedMemory("key-img",this);
    qDebug()<<pSharedMen->isAttached();
    if(pSharedMen->isAttached() == false)
        pSharedMen->attach();
    pSharedMen->lock();
    buffer.setData(static_cast<const char*>(pSharedMen->constData()),pSharedMen->size());
    buffer.open(QBuffer::ReadWrite);
    in>>pixmap;
    pSharedMen->unlock();
    pSharedMen->detach();

    QWidget *w = new QWidget;
    w->resize(400,400);
    w->show();
    QLabel *label = new QLabel(w);
    label->resize(400,400);
    label->setPixmap(pixmap);
    label->show();
}