Cannot modify height value from QRect

Question

The follow snippet results in my compilation yielding "error: passing 'const QRect' as 'this' argument of 'void QRect::setHeight(int)' discards qualifiers [-fpermissive]".

How can I fix this and also I've noticed that if I were to replace h -= 80; with h--;, the compiler does not complain.

int h = this->geometry().height();
h -= 80;
ui->datumTable->geometry().setHeight(h);

Either the `datumTable` object or the `geometry` function has been marked as `const`. I.e. they can't be modified. — Some programmer dude, May 20 '13 at 14:01

Alex B · Accepted Answer · 2013-05-20T14:10:57.013

2

geometry() returns a const reference to a QRect object inside QTableWidget.

It's meant to be a read-only getter. You should take a copy, modify it and set it back with setGeometry setter function:

QRect rect = this->geometry();
int h = rect.height();
rect.setHeight(h - 80);
ui->datumTable->setGeometry(rect);

edited May 20 '13 at 14:10

answered May 20 '13 at 14:04

Alex B

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score 1 · Answer 2 · answered May 20 '13 at 14:05

1

QRect g = this->geometry().height();
g.setHeight(g.height()-80);
ui->datumTable->setGeometry(g);

answered May 20 '13 at 14:05

Dan Milburn

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score 0 · Answer 3 · answered May 20 '13 at 14:01

0

It would seem that geometry() in datumTable returns a const QRect. Not an easy fix unless there is a non-const version as well.

answered May 20 '13 at 14:01

Mats Petersson

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pretty sure the same code has worked in qt on windows, could this be a linux variant problem/bug ? This needn't be a difficult problem – johnsonwi May 20 '13 at 14:03
@johnsonwi Because the returned value is a const reference, so the compiler won't let you modify it. – Alex B May 20 '13 at 14:12

Cannot modify height value from QRect

3 Answers3