Size Difference

Hi, I'm just wondering why there is a size difference between a widget in a window

e.g. in design viewer it's 600 x 450

and when I write this->width(); and this->height(); I get 596 x 456.

Doesn't take a rocket scientist to figure out that there is a 4 pixel difference there (is that always going to be the case???), however I'm failing to understand why it's there in the first place? Just accept it, account for it and move on?

If the widget on a layout, then the layout will decide the size (unless fixed size widget).

The size from designer to run time should not change.

I have made the widget as big as the window will go and it remains proportional to the size of the window when I resize the window, however the size of the window in designer is a different size under 'geometry' than when i 'fetch' the size of this widget form within my program and I'm not sure where the difference comes from?

It is important note that geometry() will return a proper position and size only after the widget is displayed (i.e. show() is called and painted)

Quote:

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I have made the widget as big as the window will go and it remains proportional to the size of the window when I resize the window

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Does that mean you have one widget on a top level widget?
When say resize and propostional, it kind of implies that you are using some layout manager. As I said earlier the layout manager will resize (change the widget size) to fit it into the parent window/widget, and will also add the margins. These margins will cause the widget to shrink.

If you are using layouts then use setMargins(0);

I tried to get the geomtery of the widget inside the OpenGL PainGL function, so it's certainly after show(). I did not create the widget via code from a clean slate, I used 'Design Editor'. As you can somewhat see in the attachment, the widget is centre adjusted for height and width, so it will always have the border as seen there - which is fine, however why there is a discrepancy between its geometry in design and when I run the app (before I attempt to re-size the window obviously), is quite surprising.

Attachment 9309

I cannot see the attachment clearly, but it seems your problem is with layout margin. Did you try setting setMargin(0)?