alt Hacker News> The scale factor can be something quirky like your 1.785, and the GUI code will generally make sure that things nevertheless snap to the pixel grid to avoid blurry results
This is horrifying! It implies that, for some scaling factors, the lines of text of your terminal will be of different height.
Not that the alternative (pretend that characters can be placed at arbitrary sub-pixel positions) is any less horrifying. This would make all the lines in your terminal of the same height, alright, but then the same character at different lines would look different.
The bitter truth is that fractional scaling is impossible. You cannot simply scale images without blurring them. Think about an alternating pattern of white and black rows of pixels. If you try to scale it to a non-integer factor the result will be either blurry or aliased.
The good news is that fractional scaling is unnecessary. You can just use fonts of any size you want. Moreover, nowadays pixels are so small that you can simply use large bitmap fonts and they'll look sharp, clean and beautiful.
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The way it works for your terminal emulator example is that it figures out what makes sense to do for a value of 1.785, e.g. rasterizing text appropriately and making sure that line heights and baselines are at sensible consistent values.
> The bitter truth is that fractional scaling is impossible.
That's overly prescriptive in terms of what users want. In my experience users who are used to macOS don't mind slightly blurred text. And users who are traditionalists and perhaps Windows users prefer crisper text at the expense of some height mismatches. It's all very subjective.