<https://forums.getpaint.net/topic/826-please-add-constrained-selection-option/#comment-2872>
<http://schema.org/text>
"There is a way to do this. \nSelect an area (if you can get it to be the proper ratio at this time, go for it).  Next, click on the \"Move Selection\" tool, which is down and to the right from the \"Rectangle Select\" tool.  Now, either adjust the arrows until you get the right ratio, or go on to the next step if you have the ratio already.  To resize the selection, and keep the ratio, hold down Shift on your keyboard while dragging one of the handles.  This preserves the ratio of the selection box.  Then just crop it... "
<https://forums.getpaint.net/topic/826-please-add-constrained-selection-option/>