qt写一个录制glf的demo

学习c++，qt也有半个月了，也看了前辈的好多代码，今天试着自己写一个demo验证一下最近的学习情况。

首先看一下最终的样式吧。

这个功能并不是特别复杂。贴代码

#pragma execution_character_set("utf-8")
#include "gifform.h"
#include<QScopedPointer>
#include<QMutex>
#include<QVBoxLayout>
#include<QPushButton>
#include<QLabel>
#include<QStyle>
#include<QMouseEvent>
#include<QPainter>
#include<QScreen>
#include<QApplication>
#include<QFileDialog>
#include<QTextCodec>
#include<QDesktopServices>

QScopedPointer<gifform> gifform::self;
//单例函数，用来实例化本窗体
gifform *gifform::instance(){
    //判断智能指针是否是空得
    if(self.isNull())
    {
        //加个单例锁
        static QMutex mutex;
        QMutexLocker locker(&mutex);
        if(self.isNull()){
            self.reset(new gifform);
        }

    }
    return self.data();//返回实例好的窗体
}

gifform::gifform(QWidget *parent) :
    QDialog(parent)
{
    this->initControl();
    this->initForm();

}
void gifform::initControl()
{
    this->setObjectName("GifWidget");
    this->resize(800, 600);
    this->setSizeGripEnabled(true);
    QVBoxLayout *verticalLayout = new QVBoxLayout(this);
    verticalLayout->setSpacing(0);
    verticalLayout->setContentsMargins(11, 11, 11, 11);
    verticalLayout->setObjectName("verticalLayout");
    verticalLayout->setContentsMargins(0, 0, 0, 0);

    widgetTop = new QWidget(this);
    widgetTop->setObjectName("widgetTop");
    widgetTop->setMinimumSize(QSize(0, 35));
    widgetTop->setMaximumSize(QSize(16777215, 35));

    QHBoxLayout *layoutTop = new QHBoxLayout(widgetTop);
    layoutTop->setSpacing(0);
    layoutTop->setContentsMargins(11, 11, 11, 11);
    layoutTop->setObjectName("layoutTop");
    layoutTop->setContentsMargins(0, 0, 0, 0);

    QPushButton *btnIcon = new QPushButton(widgetTop);
    btnIcon->setObjectName("btnIcon");
    QSizePolicy sizePolicy(QSizePolicy::Minimum, QSizePolicy::Expanding);
    sizePolicy.setHorizontalStretch(0);
    sizePolicy.setVerticalStretch(0);
    sizePolicy.setHeightForWidth(btnIcon->sizePolicy().hasHeightForWidth());
    btnIcon->setSizePolicy(sizePolicy);
    btnIcon->setMinimumSize(QSize(35, 0));
    btnIcon->setFlat(true);
    layoutTop->addWidget(btnIcon);

    QLabel *labTitle = new QLabel(widgetTop);
    labTitle->setObjectName("labTitle");
    layoutTop->addWidget(labTitle);

    QSpacerItem *horizontalSpacer = new QSpacerItem(87, 20, QSizePolicy::Expanding, QSizePolicy::Minimum);
    layoutTop->addItem(horizontalSpacer);

    QPushButton *btnClose = new QPushButton(widgetTop);
    btnClose->setObjectName("btnClose");
    sizePolicy.setHeightForWidth(btnClose->sizePolicy().hasHeightForWidth());
    btnClose->setSizePolicy(sizePolicy);
    btnClose->setMinimumSize(QSize(35, 0));
    btnClose->setFocusPolicy(Qt::NoFocus);
    btnClose->setFlat(true);
    layoutTop->addWidget(btnClose);
    verticalLayout->addWidget(widgetTop);

    widgetMain = new QWidget(this);
    widgetMain->setObjectName("widgetMain");
    QSizePolicy sizePolicy1(QSizePolicy::Preferred, QSizePolicy::Expanding);
    sizePolicy1.setHorizontalStretch(0);
    sizePolicy1.setVerticalStretch(0);
    sizePolicy1.setHeightForWidth(widgetMain->sizePolicy().hasHeightForWidth());
    widgetMain->setSizePolicy(sizePolicy1);
    verticalLayout->addWidget(widgetMain);

    widgetBottom = new QWidget(this);
    widgetBottom->setObjectName("widgetBottom");
    widgetBottom->setMinimumSize(QSize(0, 45));
    widgetBottom->setMaximumSize(QSize(16777215, 45));

    QHBoxLayout *layoutBottom = new QHBoxLayout(widgetBottom);
    layoutBottom->setSpacing(6);
    layoutBottom->setContentsMargins(11, 11, 11, 11);
    layoutBottom->setObjectName("layoutBottom");
    layoutBottom->setContentsMargins(9, 9, -1, -1);

    QLabel *labFps = new QLabel(widgetBottom);
    labFps->setObjectName("labFps");
    layoutBottom->addWidget(labFps);

    txtFps = new QLineEdit(widgetBottom);
    txtFps->setObjectName("txtFps");
    txtFps->setMaximumSize(QSize(50, 16777215));
    txtFps->setAlignment(Qt::AlignCenter);
    layoutBottom->addWidget(txtFps);

    QLabel *labWidth = new QLabel(widgetBottom);
    labWidth->setObjectName("labWidth");
    layoutBottom->addWidget(labWidth);

    txtWidth = new QLineEdit(widgetBottom);
    txtWidth->setObjectName("txtWidth");
    txtWidth->setEnabled(true);
    txtWidth->setMaximumSize(QSize(50, 16777215));
    txtWidth->setAlignment(Qt::AlignCenter);
    layoutBottom->addWidget(txtWidth);

    QLabel *labHeight = new QLabel(widgetBottom);
    labHeight->setObjectName("labHeight");
    layoutBottom->addWidget(labHeight);

    txtHeight = new QLineEdit(widgetBottom);
    txtHeight->setObjectName("txtHeight");
    txtHeight->setEnabled(true);
    txtHeight->setMaximumSize(QSize(50, 16777215));
    txtHeight->setAlignment(Qt::AlignCenter);
    layoutBottom->addWidget(txtHeight);

    labStatus = new QLabel(widgetBottom);
    labStatus->setObjectName("labStatus");
    QSizePolicy sizePolicy2(QSizePolicy::Expanding, QSizePolicy::Preferred);
    sizePolicy2.setHorizontalStretch(0);
    sizePolicy2.setVerticalStretch(0);
    sizePolicy2.setHeightForWidth(labStatus->sizePolicy().hasHeightForWidth());
    labStatus->setSizePolicy(sizePolicy2);
    labStatus->setAlignment(Qt::AlignCenter);
    layoutBottom->addWidget(labStatus);

    btnStart = new QPushButton(widgetBottom);
    btnStart->setObjectName("btnStart");
    sizePolicy.setHeightForWidth(btnStart->sizePolicy().hasHeightForWidth());
    btnStart->setSizePolicy(sizePolicy);
    layoutBottom->addWidget(btnStart);
    verticalLayout->addWidget(widgetBottom);

    labTitle->setText("录屏测试");
    labFps->setText("帧率");
    labWidth->setText("宽度");
    labHeight->setText("高度");
    btnStart->setText("开始");
    this->setWindowTitle(labTitle->text());

    btnIcon->setIcon(style()->standardIcon(QStyle::SP_ComputerIcon));
    btnClose->setIcon(style()->standardIcon(QStyle::SP_TitleBarCloseButton));

    connect(btnClose, SIGNAL(clicked(bool)), this, SLOT(closeAll()));
    connect(btnStart, SIGNAL(clicked(bool)), this, SLOT(record()));
    connect(txtWidth, SIGNAL(editingFinished()), this, SLOT(resizeForm()));
    connect(txtHeight, SIGNAL(editingFinished()), this, SLOT(resizeForm()));
}



void gifform::initForm(){
    borderWidth = 3;
    bgColor = QColor(34, 50, 169);

    fps = 10;
    txtFps->setText(QString::number(fps));
    //gifWriter = 0;

    timer = new QTimer(this);
    timer->setInterval(100);
    //定时任务保存图片
    connect(timer, SIGNAL(timeout()), this, SLOT(saveImage()));
    //这两行代码的意思是将窗体透明化
    this->setAttribute(Qt::WA_TranslucentBackground);
    this->setWindowFlags(Qt::FramelessWindowHint);
    this->installEventFilter(this); //安装事件过滤器

    QStringList qss;
    qss.append("QLabel{color:#ffffff;}");
    qss.append("#btnClose,#btnIcon{border:none;border-radius:0px;}");
    qss.append("#btnClose:hover{background-color:#ff0000;}");
    qss.append("#btnClose{border-top-right-radius:5px;}");
    qss.append("#labTitle{font:bold 16px;}");
    qss.append("#labStatus{font:15px;}");
    this->setStyleSheet(qss.join(""));
}
//关闭的按钮
void gifform::closeAll(){
    //释放
    if (0 != gifWriter) {
        delete gifWriter;
        gifWriter = 0;
    }

    this->close();

}
//保存图片的操作，由定时任务控制
void gifform::saveImage(){
    if (!gifWriter) {
        return;
    }

#if (QT_VERSION >= QT_VERSION_CHECK(5,0,0))
    QScreen *screen = QApplication::primaryScreen();//获取屏幕
    QPixmap pix = screen->grabWindow(0, x() + rectGif.x(), y() + rectGif.y(), rectGif.width(), rectGif.height()); //截取指定大小得像素图片
    QImage image = pix.toImage().convertToFormat(QImage::Format_RGBA8888);  //转换为图片
#else
    //由于qt4没有RGBA8888,采用最接近RGBA8888的是ARGB32,颜色会有点偏差
    QPixmap pix = QPixmap::grabWindow(0, x() + rectGif.x(), y() + rectGif.y(), rectGif.width(), rectGif.height());
    QImage image = pix.toImage().convertToFormat(QImage::Format_ARGB32);
#endif

    gif.GifWriteFrame(gifWriter, image.bits(), rectGif.width(), rectGif.height(), fps);  //打印到字节流
    count++;
    labStatus->setText(QString("正在录制 第 %1 帧").arg(count));

}
//宽度和高度的文本框数值改变触发此事件
void gifform::resizeForm(){
    int width = txtWidth->text().toInt();     //获取文本框的值转换成int类型
    int height = txtHeight->text().toInt();
    this->resize(width, height + widgetTop->height() + widgetBottom->height());  //此函数重置窗体大小
}
//开始和关闭的函数
void gifform::record(){
    if (btnStart->text() == "开始") {
        //判断上一次是否释放成功，如果没有释放成功，重新释放
        if (0 != gifWriter) {
            delete gifWriter;
            gifWriter = 0;
        }

        //先弹出文件保存对话框
        //fileName = qApp->applicationDirPath() + "/" + QDateTime::currentDateTime().toString("yyyy-MM-dd-hh-mm-ss.gif");
        fileName = QFileDialog::getSaveFileName(this, "选择保存位置", qApp->applicationDirPath() + "/", "gif图片(*.gif)");
        if (fileName.isEmpty()) {
            return;
        }

        int width = txtWidth->text().toInt();
        int height = txtHeight->text().toInt();
        fps = txtFps->text().toInt();

#ifdef Q_OS_WIN
        //windows上需要先转码
#if defined(_MSC_VER) && (_MSC_VER >= 1400)
        QTextCodec *code = QTextCodec::codecForName("utf-8");
#else
        QTextCodec *code = QTextCodec::codecForName("gbk");
#endif
        const char *name = code->fromUnicode(fileName).constData();
#else
        const char *name = fileName.toUtf8().constData();
#endif

        gifWriter = new Gif::GifWriter;  //在这个位置实例化glfwriter类
        bool ok = gif.GifBegin(gifWriter, name, width, height, fps);  //开始制作glf
        //如果失败  执行上一次
        if (!ok) {
            delete gifWriter;
            gifWriter = 0;
            return;
        }

        count = 0;
        labStatus->setText("开始录制...");
        btnStart->setText("停止");
        //延时启动
        timer->setInterval(1000 / fps);
        QTimer::singleShot(1000, timer, SLOT(start())); //开始定时任务
        //saveImage();
    } else {
        //停止  结束 保存 释放
        timer->stop();
        gif.GifEnd(gifWriter);

        delete gifWriter;
        gifWriter = 0;

        labStatus->setText(QString("录制完成 共 %1 帧").arg(count));
        btnStart->setText("开始");
        QDesktopServices::openUrl(QUrl::fromLocalFile(fileName)); //调用电脑的图片查看器，打开保存位置的
    }

}
//这个函数的意思是从这里读取边框的宽度
int gifform::getBorderWidth() const{
    return this->borderWidth;
}
void gifform::setBorderWidth(int borderWidth)
{
    if (this->borderWidth != borderWidth) {
        this->borderWidth = borderWidth;
        this->update();
    }
}
QColor gifform::getBgColor() const
{
    return this->bgColor;
}
void gifform::setBgColor(const QColor &bgColor)
{
    if (this->bgColor != bgColor) {
        this->bgColor = bgColor;
        this->update();
    }
}
void gifform::resizeEvent(QResizeEvent *e)
{
    //拉动右下角改变大小自动赋值
    txtWidth->setText(QString::number(widgetMain->width()));
    txtHeight->setText(QString::number(widgetMain->height()));
    QDialog::resizeEvent(e);
}
//事件过滤器，主要就是解决窗体在去掉边框之后无法移动
bool gifform::eventFilter(QObject *watched, QEvent *event)
{
    static QPoint mousePoint;
    static bool mousePressed = false;
    //强制类型转换为QMouseEvent

    QMouseEvent *mouseEvent = static_cast<QMouseEvent *>(event);
    if (mouseEvent->type() == QEvent::MouseButtonPress) {
        if (mouseEvent->button() == Qt::LeftButton) {
            mousePressed = true;
            mousePoint = mouseEvent->globalPos() - this->pos();
            return true;
        }
    } else if (mouseEvent->type() == QEvent::MouseButtonRelease) {
        mousePressed = false;
        return true;
    } else if (mouseEvent->type() == QEvent::MouseMove) {
        if (mousePressed) {
            this->move(mouseEvent->globalPos() - mousePoint);
            return true;
        }
    }

    return QWidget::eventFilter(watched, event);
}
//主要就是绘制窗体的边框
void gifform::paintEvent(QPaintEvent *)
{
    int width = txtWidth->text().toInt();
    int height = txtHeight->text().toInt();
    rectGif = QRect(borderWidth, widgetTop->height(), width - (borderWidth * 2), height);

    QPainter painter(this);
    painter.setPen(Qt::NoPen);
    painter.setBrush(bgColor);
    painter.drawRoundedRect(this->rect(), 5, 5);
    painter.setCompositionMode(QPainter::CompositionMode_Clear);
    painter.fillRect(rectGif, Qt::SolidPattern);
}

以上是程序的所有逻辑，没有特别复杂，新手练手用用可以。

https://gitee.com/parrotfamily/qtdemo