I am using a 4K monitor. LTSpice does not render very well at this resolution (3840 x 2160). The wires and other features are extremely small, which makes the app very difficult to use. I believe that the rendering is fixed at 1 pixel width regardless of resolution. For my particular monitor size that means the wires are physically about 0.006" (150 um) wide, which is obviously very, very thin. Zooming in and out has no effect, it increases the size of the objects but not the width of the lines that make them up.
I tried overriding the scaling using standards Windows settings. That workaround will generally force old school applications to render better. In the case of LTSpice that had some negative side effects like making the cursor disappear so it was ultimately not useable.
Will proper high DPI support for LTSpice be rolled out at some point? I suspect more and more people are buying high DPI monitors as time goes on. It's a shame that such a nice tool really isn't very usable on modern hardware.
You can adapt some settings:
Tools -> Control Panel -> Drafting Options -> Pen Thickness, Font Properties (for schematic entry)
Tools -> Control Panel -> Waveforms -> Data Trace Width, Cursor…
Tools -> Control Panel -> Waveforms -> Data Trace Width, Cursor Width, Font Point Size (for waveform viewer)
Tools -> Control Panel -> Operation -> Toolbar Icon Size
Thanks Reiner! Also, LOL at the "Yuge" toolbar size. Nice easter egg.If I may make a suggestion, it'd be awesome if LTSpice would automatically bump up the options when it detects a high res monitor!