c++ - Sortable QHBoxLayout

Question

I'm using Qt to create a sortable bar graph-like widget. The widget is laid out with a QHBoxLayout for each bar in the graph (which are also widgets).

When the user changes the sorting parameters, my controller clears the layout, sorts it, and calls addWidget on every item in order. The problem I'm facing is that this list is quite large (1000+ widgets), and Qt is crawling when attempting to layout that many elements.

I've found out that each time addWidget is called, Qt will recalculate the location of every item in the QHBoxLayout and then update. This is a problem, as it performs a lot of unnecessary calculations on each LayoutItem before the one I am adding. For 1000 test items that I'm putting in, resorting takes around 30 seconds, which is obviously far too long.

Is there a better Layout type to use, or is there a faster way to add a collection of sorted widgets to a layout?

Edit: Apparently, the issue I've been having isn't with Qt laying out each item again, but the internals of all the parenting and shenanigans that go on behind the scenes I set up a test project to add 1000 buttons to a layout, printing out a counter each time. The numbers printed out almost instantaneously, though it took that same ~30 seconds for Qt to straighten itself out. I think the problem doesn't exist only with QHBoxLayout, but with Qt's layout system in general. Looks like I'll be manually positioning widgets and bypassing a QLayout altogether. Thanks to everyone who gave their input.

Answer 1

From documenation of void QLayout::setEnabled(bool enable)

Enables this layout if enable is true, otherwise disables it.
An enabled layout adjusts dynamically to changes; a disabled layout acts as if it did not exist.
By default all layouts are enabled.