Preface: This article is about the matter of "scaling" or "setting the scale" for your layout. If you intend to place a scale as an image to your frontpanel design, please have a look here: Insert a scale

You will find this function within the extension of ZoomIn.jpg under Scale.jpg

How to set the zoom factor
Image: The dialog to set the zoom factor

The scale function allows to enter a zoom-factor for the window. 100% means that 1 cm PCB = 1 cm on the screen = world coordinates. You can set units inch, mil and mm (1 inch = 1 = 25,4mm; 1 mil = 1/1000 = 0,0254mm). To allow a display of world coordinates you have to enter the exact usable size of your screen in menu Settings-Settings/Options.

How to set the usable monitor size
Image: How to set the usable monitor size. Take a ruler and measure the inner dimensions of your screen (all what is lucent - excluding the frame).

Also seePrint. Scale, Offset, Correction.
Also seeToolbar