variable widgetsize in gridlayout

[Surfman19]

Hello,

i have the following elements in the gridLayout:

ui->gridLayout->addWidget(&textedit);
ui->gridLayout->addWidget(&label);
ui->gridLayout->addWidget(&plot);
ui->gridLayout->setRowStretch(1, 1);
ui->gridLayout->setRowStretch(3, 3);

ui->gridLayout->addWidget(&textedit);
ui->gridLayout->addWidget(&label);
ui->gridLayout->addWidget(&plot);
ui->gridLayout->setRowStretch(1, 1);
ui->gridLayout->setRowStretch(3, 3);

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I would like to dynamically change widget size. if i give plot more space, the textedit space should get smaller...
how to achieve that?

i need some sort of splitter between the widgets... and i should be able to move the splitter up and down...
if the splitter gets moved up, the widget below will resize and increase its size...

will i need to add all widgets to qsplitter?