Hello!
You show a very nice photo of a very ugly display. The gaps between the pixels are too big, the dpi quite low, so I do have problems to read this display.
You suggest a variable gap between pixels.
i) Which HP calculator does offer a similar feature?
ii) In the photo you show the display-"dots" are about 12x12 pixels (of the photo), the gaps about 4 pels wide, so the ratio is ~3/1. As the gap can not be smaller than one pixel the minimum dot+gap space will be 4x4 pixels. To get smaller gaps you must draw bigger dots, 4+1 or 5+1 (dot+gap). Now multiply this with the display resolution of an HP48 to get the virtual calculator's screen size, next zoom a photo of the calculator accordingly so the emulator's display fits nicely. And now tell me if your CRT or monitor or LCD projector or whatever you use with your PC has a big enough resolution to show all calculator keys you need to get any use out of it.
To simulate the display as close as possible to the original is not trivial. Some calculators have "italic" numbers, have a small slant angle. To make an illusion of this on your PC screen with only upright pixels you need halftone rendering. What leads to another long term pipe dream: stepless zooming. Rusty Wagner's vTI offers this feature, alas with a somewhat poor rendering so only discrete zoom factors are useful.
BTW, I do not know where to get a good rendering algorithm (even the Paint Shop Pro I use offers serval for resizing photos) and if I had one I would not know how to implement it in the calculator emulator. I could immagine to keep a hidden view of the calculator and display it zoomed with a free tool like LXpic.
You see, I have a list of wishes too but not time to get there.
Ciao.....Mike