Square aspect ratio doesn't work with very wide images and 'with rgbimage'

[Dima K. <gn...@di...>]

Hi.

I have a very VERY non-square image file (attached). This is a 4000x20
png. I want to use gnuplot to plot it with a square aspect ratio. (In my
actual use case, I'd plot stuff on top of it). I do this:

  set size ratio -1
  plot "wide.png" binary filetype=auto with rgbimage

Normally this works, but with such a wide image the "set size ratio -1"
doesn't work: the image is scaled to fill the plot, and I get very tall
and very skinny pixels. If I zoom in with

  Ctrl-Shift-MouseWheelUp

then it gets unconfused after a few cycles. I bet there's something
hardcoded in the scaling logic. Can somebody please take a look?