1 inch ruler viewed at 100% does NOT appear as 1 inch. HELP!

[aaronc08]

I created images with a canvas size of 8.5" x 11" on an old laptop. Recently purchased a new laptop, downloaded paint.net, opened my previous images and they are now visually smaller on the screen at 100%. I'm looking at the paint.net and the inches viewed on my laptop don't look like a true to size inch when viewed at 100%. If I change the view to 150%, the inch on paint.net looks more true to size as an actual visual inch on the screen, but on my old laptop, viewing an inch on the screen at 100% was exactly 1 inch visually. This isn't the case anymore. Can someone help me?

[Rick Brewster]

The inches in the app are meant to represent the image's mapping from pixels to inches, if the image were to be printed. They don't necessarily correspond to inches on your monitor, unless the image's DPI is an exact match for your monitor's DPI.

 

First the image is drawn with pixel-to-pixel mapping from the image to the screen. Then the measurement from the image's resolution (DPI) to inches (or centimeters) is performed and the ruler is drawn. The ruler does not correspond to the physical size of your monitor. In fact, there isn't any way for the app to accurately do this in the first place. "Dots Per Inch" has been a major misnomer since just a few minutes after it was incorrectly used for computer displays. It's never been correctly used that way, and that's why Windows now uses percentage scaling instead of "DPI". Same code, different vocabulary, but makes way more sense now.