Useful, but doesn’t scale independently

I have a very high DPI MacBook Pro Retina, and a very low DPI 1080p monitor next to it. In the past I’ve gone to great lengths to get my multiscreen wallpaper to line up across both screens. This does half of the job - it let’s me grab 2 chunks of the image according to the resolutions of the monitors, but it doesn’t take into account the DPI, so the images have completely different scales and can only align at one point. I would like to able to calibrate the relative sizes of my monitors so it can scale the image for one of the screens to match the other. Maybe you could draw two lines between the screens, then give me position and scale controls to adjust until both of the lines connect. Maybe too much to ask for in a $3 app, but very useful with the increasing range of screen densities.

wilcoxst about Multi Monitor Wallpaper