Question

I think this is a very simple question, but when I copy an image I can’t paste it in a QTextEdit? Paste is inactive! Also I would like to know how to drag-and-drop a picture.

BTW I use the following code in order to insert a picture into a QTextEdit:

QTextEdit *textEditor = new QTextEdit(0);
QTextDocumentFragment fragment;
fragment = QTextDocumentFragment::fromHtml("<img src='C:\\aaa.jpg'>");
textEditor->textCursor().insertFragment(fragment);
textEditor->setVisible(true);

Is it recommended? How do you do this operation?

Answer 1

The second way is this:

void TextEdit::insertImage()
{
    QString file = QFileDialog::getOpenFileName(this, tr("Select an image"),
                                  ".", tr("Bitmap Files (*.bmp)\n"
                                    "JPEG (*.jpg *jpeg)\n"
                                    "GIF (*.gif)\n"
                                    "PNG (*.png)\n"));
    QUrl Uri ( QString ( "file://%1" ).arg ( file ) );
    QImage image = QImageReader ( file ).read();

    QTextDocument * textDocument = m_textEdit->document();
    textDocument->addResource( QTextDocument::ImageResource, Uri, QVariant ( image ) );
    QTextCursor cursor = m_textEdit->textCursor();
    QTextImageFormat imageFormat;
    imageFormat.setWidth( image.width() );
    imageFormat.setHeight( image.height() );
    imageFormat.setName( Uri.toString() );
    cursor.insertImage(imageFormat);
 }

The third way is to inherit QTextEdit and reimplement canInsertFromMimeData and insertFromMimeData functions as follows. By the way this method allows to use drag-and-drop or copy-paste mechanisms.

class TextEdit : public QTextEdit
{
public:
    bool canInsertFromMimeData(const QMimeData* source) const
    {
        return source->hasImage() || source->hasUrls() ||
            QTextEdit::canInsertFromMimeData(source);
    }

    void insertFromMimeData(const QMimeData* source)
    {
        if (source->hasImage())
        {
            static int i = 1;
            QUrl url(QString("dropped_image_%1").arg(i++));
            dropImage(url, qvariant_cast<QImage>(source->imageData()));
        }
        else if (source->hasUrls())
        {
            foreach (QUrl url, source->urls())
            {
                QFileInfo info(url.toLocalFile());
                if (QImageReader::supportedImageFormats().contains(info.suffix().toLower().toLatin1()))
                    dropImage(url, QImage(info.filePath()));
                else
                    dropTextFile(url);
            }
        }
        else
        {
            QTextEdit::insertFromMimeData(source);
        }
    }

private:
    void dropImage(const QUrl& url, const QImage& image)
    {
        if (!image.isNull())
        {
            document()->addResource(QTextDocument::ImageResource, url, image);
            textCursor().insertImage(url.toString());
        }
    }

    void dropTextFile(const QUrl& url)
    {
        QFile file(url.toLocalFile());
        if (file.open(QIODevice::ReadOnly | QIODevice::Text))
            textCursor().insertText(file.readAll());
    }
};

Just wanted to share what I have found during long investigation :).