《QT实用小工具·四十四》支持图片和动图的文本编辑器

1、概述
源码放在文章末尾

该项目实现了一个功能丰富的文本编辑器，除了包含文本常规的编辑功能，还包括图片的插入功能和动图的插入功能，项目demo演示如下所示：

项目部分代码如下所示：

#include "imagehelper.h"

#include <QFile>
#include <QFileInfo>
#include <QQmlFile>
#include <QQuickTextDocument>
#include <QDebug>

Api::Api(QObject *parent)
    : QObject(parent)
{
}

bool Api::exists(const QString &arg)
{
    return QFile::exists(arg);
}

QString Api::baseName(const QString &arg)
{
    return QFileInfo(arg).baseName();
}

ImageHelper::ImageHelper(QObject *parent)
    : QObject(parent),
      m_maxWidth(120),
      m_maxHeight(120)
{

}

ImageHelper::~ImageHelper()
{
    cleanup();
}

void ImageHelper::insertImage(const QUrl &url)
{
    QImage image = QImage(QQmlFile::urlToLocalFileOrQrc(url));
    if (image.isNull())
    {
        qDebug() << "不支持的图像格式";
        return;
    }
    QString filename = url.toString();
    QString suffix = QFileInfo(filename).suffix();
    if (suffix == "GIF" || suffix == "gif") //如果是gif，则单独处理
    {
        QString gif = filename;
        if (gif.left(4) == "file")
            gif = gif.mid(8);
        else if (gif.left(3) == "qrc")
            gif = gif.mid(3);

        textCursor().insertHtml("<img src='" + url.toString() + "' width = " +
                                QString::number(qMin(m_maxWidth, image.width())) + " height = " +
                                QString::number(qMin(m_maxHeight, image.height()))+ "/>");
        textDocument()->addResource(QTextDocument::ImageResource, url, image);
        if (m_urls.contains(url))
            return;
        else
        {
            QMovie *movie = new QMovie(gif);
            movie->setCacheMode(QMovie::CacheNone);
            connect(movie, &QMovie::finished, movie, &QMovie::start);   //循环播放
            connect(movie, &QMovie::frameChanged, this, [url, this](int)
            {
                QMovie *movie = qobject_cast<QMovie *>(sender());
                textDocument()->addResource(QTextDocument::ImageResource, url, movie->currentPixmap());
                emit needUpdate();
            });
            m_urls[url] = movie;
            movie->start();
        }
    }
    else
    {        
        QTextImageFormat format;
        format.setName(filename);
        format.setWidth(qMin(m_maxWidth, image.width()));
        format.setHeight(qMin(m_maxHeight, image.height()));
        textCursor().insertImage(format, QTextFrameFormat::InFlow);
    }
}

void ImageHelper::cleanup()
{
    for (auto it : m_urls)
        it->deleteLater();
    m_urls.clear();
}

QQuickTextDocument* ImageHelper::document() const
{
    return  m_document;
}

void ImageHelper::setDocument(QQuickTextDocument *document)
{
    if (document != m_document)
    {
        m_document = document;
        emit documentChanged();
    }
}

int ImageHelper::cursorPosition() const
{
    return m_cursorPosition;
}

void ImageHelper::setCursorPosition(int position)
{
    if (position != m_cursorPosition)
    {
        m_cursorPosition = position;
        emit cursorPositionChanged();
    }
}

int ImageHelper::selectionStart() const
{
    return m_selectionStart;
}

void ImageHelper::setSelectionStart(int position)
{
    if (position != m_selectionStart)
    {
        m_selectionStart = position;
        emit selectionStartChanged();
    }
}

int ImageHelper::selectionEnd() const
{
    return m_selectionEnd;
}

void ImageHelper::setSelectionEnd(int position)
{
    if (position != m_selectionEnd)
    {
        m_selectionEnd = position;
        emit selectionEndChanged();
    }
}

int ImageHelper::maxWidth() const
{
    return m_maxWidth;
}

void ImageHelper::setMaxWidth(int max)
{
    if (max != m_maxWidth)
    {
        m_maxWidth = max;
        emit maxWidthChanged();
    }
}

int ImageHelper::maxHeight() const
{
    return m_maxHeight;
}

void ImageHelper::setMaxHeight(int max)
{
    if (max != m_maxHeight)
    {
        m_maxHeight = max;
        emit maxHeightChanged();
    }
}

QTextDocument* ImageHelper::textDocument() const
{
    if (m_document)
        return m_document->textDocument();
    else return nullptr;
}

QTextCursor ImageHelper::textCursor() const
{
    QTextDocument *doc = textDocument();
    if (!doc)
        return QTextCursor();

    QTextCursor cursor = QTextCursor(doc);
    if (m_selectionStart != m_selectionEnd)
    {
        cursor.setPosition(m_selectionStart);
        cursor.setPosition(m_selectionEnd, QTextCursor::KeepAnchor);
    }
    else
    {
        cursor.setPosition(m_cursorPosition);
    }

    return cursor;
}

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