How to take a screenshot on Mac while keeping the aspect ratio of the capture area I know I can open the Screenshot tool by pressing cmd + shift + 4.
I can drag the mouse around to specify the area I want to take a screenshot of, but I am wondering how I can keep the width and height ratio 1:1 when moving the mouse cursor.

In image editing software, the combination is usually to hold shift while dragging. On mac using the screenshot tool, this means to lock one of the axis depending on where you start your drag motion. It locks the width if you start dragging up or down, and locks the height if you start dragging left or right.

Pressing alt on the other hand makes the capture area grow in both direction.

holding either cmd or ctrl seems to do nothing.

I really hope there is a key combination to make the width and height scale the same, but I cannot figure out which key combination to use.

EDIT

My version of macOS is Mojave 10.14.5.

And just to clarify, I want to keep the selection area to grow and remain at 1:1 ratio while actually moving the cursor around, similar to this:



Alternatively resizing the area in equal proportion to each other, meaning the width and the height changes so that the original aspect ratio is intact. The resulting image itself does not have to be 1:1
As far as I know the exact thing you are trying to do is not natively possible in the current version of macOS Mojave. The current modifiers that do exist for the screenshot tool are as follows:


Holding shift  moves only one of the sides of the capture area.
Holding option scales up all sides of the capture area from the center.
Holding space  allows you to move the capture area around.


Alternatively you can use shiftcommand5    which will give you the onscreen capture controls with a few more options for resizing the capture area, however this doesn't include any options for locking the aspect ratio.