chessui | First time running and compile

Dealing with widgets that have a fixed aspect ratio is not an easy task, and some precautions must be taken in order to ensure that having an "incompatible" parent size doesn't prevent proper display.

In this case, a possible solution is to use a widget for the chessboard that uses a grid layout for all the squares and pieces.
Note that a QLabel isn't a good choice for the chessboard, as it doesn't allow a size smaller than the QPixmap, so a QWidget should be subclassed instead.

The trick is to override the resizeEvent(), ignore the base implementation (which by default adapts the geometry of the layout) and manually set the geometry based on the minimum extent between width and height.

In order to ensure that the layout has proper equal spacings even when a row or column is empty, setRowStretch() and setColumnStretch() must be called for the whole grid size.

Then, you add the pieces directly to the layout, and whenever you need to move them you can just create a helper function that uses addWidget() with the correct row/column (which will automatically "move" the widget to the new position).

Here is a possible implementation.