How to save an image (png) into a xml file

[richardander]

hi friend,

I would like to save an image into an xml file. Your help is highly appreciated!

Please help!

Richard -

[aamer4yu]

You could write the png file as QByteArray/QString in the xml, couldnt you ?
something like -
<PNGDATA>.......</PNGDATA> where PNGDATA tag holds the data for you.

[richardander]

I think the content in PNG file is binary and cann't be put in a xml file directly.

I am thinking to convert them into a text format and save in xml file. when I need to load the image, I can read the text from xml and convert back to binary.

Is there any reliable way to do this conversion or there is any other way to handle image/binary data in xml?

Thank you !

[spirit]

use QByteArray::toBase64 and QByteArray::fromBase64.

[richardander]

thank you for the input. Following is the implementation.

question:

can " in >> imageData; // extract data;" read all image file data into Qbytearray?

thank you!

QFile file( strImageFilename );
	file.open(QIODevice::ReadOnly);
	QDataStream in(&file);    // read the data serialized from the file
	QByteArray imageData;
	in >> imageData;           // extract data;
 
	// convert to ascii
	QByteArray imageData_Base64 = imageData.toBase64();
 
	// save in xml
	ImageElement.setAttribute("ImageData_Base64", imageData_Base64 );

QFile file( strImageFilename );
	file.open(QIODevice::ReadOnly);
	QDataStream in(&file);    // read the data serialized from the file
	QByteArray imageData;
	in >> imageData;           // extract data;

	// convert to ascii
	QByteArray imageData_Base64 = imageData.toBase64();

	// save in xml
	ImageElement.setAttribute("ImageData_Base64", imageData_Base64 );

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[spirit]

ctor of QString takes a QByteArray, see this.

[richardander]

The following code can't read the whole file into rawData.

What is the problem?

thank you!

// load file 
	QFile file( strImageFilename );
	file.open(QIODevice::ReadOnly);
	QDataStream in(&file);    // read the data serialized from the file
 
	char * rawData = new char [ file.size() ];
	in >> rawData;           // extract data;
	file.close();
 
	// convert to ascii
	QByteArray imageData( rawData );

// load file 
	QFile file( strImageFilename );
	file.open(QIODevice::ReadOnly);
	QDataStream in(&file);    // read the data serialized from the file

	char * rawData = new char [ file.size() ];
	in >> rawData;           // extract data;
	file.close();

	// convert to ascii
	QByteArray imageData( rawData );

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[yan]

If you want load the binary file to a QByteArray juste use readAll

QFile file( strImageFilename );
file.open(QIODevice::ReadOnly);
QByteArray imageData = file.readAll();
 QByteArray imageData_Base64 = imageData.toBase64();

QFile file( strImageFilename );
file.open(QIODevice::ReadOnly);
QByteArray imageData = file.readAll();
 QByteArray imageData_Base64 = imageData.toBase64();

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[spirit]

take a look at this example, works fine

#include <QtGui>
#include <QtSql>
#include <QtXml>
#include <QApplication>
 
int main(int argc, char **argv)
{
	QApplication app(argc, argv);
 
	QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
	db.setDatabaseName("pictures");
	if (!db.open())
		return db.lastError().number();
 
	QSqlQuery query;
	qDebug() << query.exec("CREATE TABLE IF NOT EXISTS pictures (id INT PRIMARY KEY, pic BLOB)");
 
	QImage image("flower.jpg");
	qDebug() << image.size();
	QByteArray byteArray;
	QBuffer buffer(&byteArray);
	buffer.open(QIODevice::WriteOnly);
	image.save(&buffer, "jpg");
 
	QDomDocument doc;
	QDomElement root = doc.createElement("PictureData");
	doc.appendChild(root);
	QDomText data = doc.createTextNode(byteArray.toBase64());
	root.appendChild(data);
 
	query.prepare("INSERT INTO pictures (id, pic) VALUES (?, ?)");
	query.addBindValue(1);
	query.addBindValue(doc.toString());
	qDebug() << query.exec();
 
	qDebug() << query.exec("SELECT pic FROM pictures WHERE id = 1");
	qDebug() << query.next();
 
	doc.setContent(query.value(0).toString());
	root = doc.documentElement();
	data = root.firstChild().toText();
	byteArray = QByteArray::fromBase64(data.toText().data().toAscii());
 
	QPixmap pixmap = QPixmap::fromImage(QImage::fromData(byteArray, "jpg"));
	qDebug() << pixmap.size();
 
	QLabel label;
	label.setPixmap(pixmap);
	label.show();
 
	return app.exec();
}

#include <QtGui>
#include <QtSql>
#include <QtXml>
#include <QApplication>

int main(int argc, char **argv)
{
	QApplication app(argc, argv);

	QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
	db.setDatabaseName("pictures");
	if (!db.open())
		return db.lastError().number();

	QSqlQuery query;
	qDebug() << query.exec("CREATE TABLE IF NOT EXISTS pictures (id INT PRIMARY KEY, pic BLOB)");

	QImage image("flower.jpg");
	qDebug() << image.size();
	QByteArray byteArray;
	QBuffer buffer(&byteArray);
	buffer.open(QIODevice::WriteOnly);
	image.save(&buffer, "jpg");

	QDomDocument doc;
	QDomElement root = doc.createElement("PictureData");
	doc.appendChild(root);
	QDomText data = doc.createTextNode(byteArray.toBase64());
	root.appendChild(data);

	query.prepare("INSERT INTO pictures (id, pic) VALUES (?, ?)");
	query.addBindValue(1);
	query.addBindValue(doc.toString());
	qDebug() << query.exec();

	qDebug() << query.exec("SELECT pic FROM pictures WHERE id = 1");
	qDebug() << query.next();

	doc.setContent(query.value(0).toString());
	root = doc.documentElement();
	data = root.firstChild().toText();
	byteArray = QByteArray::fromBase64(data.toText().data().toAscii());

	QPixmap pixmap = QPixmap::fromImage(QImage::fromData(byteArray, "jpg"));
	qDebug() << pixmap.size();

	QLabel label;
	label.setPixmap(pixmap);
	label.show();

	return app.exec();
}

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