#include <QApplication>
#include <QPlainTextEdit>
#include <QSplitter>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    QPlainTextEdit e1;
    e1.setPlainText("Hello really really really really really really really "
                    "really really really really really really really really "
                    "really really really really really really long World!");
    e1.setWordWrapMode(QTextOption::WrapAtWordBoundaryOrAnywhere);

    QPlainTextEdit e2;
    e2.setDocument(e1.document());
    e2.setWordWrapMode(QTextOption::WrapAtWordBoundaryOrAnywhere);

    QSplitter splitter(Qt::Horizontal);
    splitter.addWidget(&e1);
    splitter.addWidget(&e2);
    splitter.resize(300, 200);
    splitter.setSizes({200, 100});
    splitter.show();

    return a.exec();
}