bug#49688: 28.0.50; Attempting to show images crashes Emacs

[Rudolf Adamkovič]

I see. In other words, HiDPI/Retina support in Emacs is a separate 
issue. Well, I have been using EMMS heavily since you sent me the 
patch, and I did not experience a single crash. Thus, this can go 
to Emacs proper. It is so strange to use Emacs with no crashes 
throughout the day! Thank you so much for helping me.

R+

Alan Third <alan@idiocy.org> writes:

> On Sun, Jul 25, 2021 at 12:44:59AM +0200, Rudolf Adamkovič 
> wrote: 
> > TL;DR The images show pixelated.   Every modern Mac has a HiDPI 
> > (a.k.a. Retina) screen, where each point (logical pixel) maps 
> > to 4 physical pixels, a.k.a. 2× scale. I in the attached small 
> > screenshot, please compare the sharpness of the image with the 
> > text next to it. Emacs renders the image at 1× and the text at 
> > 2×. 
>
> Without knowing more about the image and how it's being 
> displayed I can't say whether there's anything wrong with that. 
>
> Images are, by default, displayed at 1x resolution so they will 
> appear the same size on retina and non-retina screens. 
>
> If you want to display images with pixels at a 1:1 ratio you 
> need to scale the image by (/ 1 (frame-scale-factor)), but that 
> will only work on Emacs 28. 
>
> This is how Emacs has always worked on retina screens, this 
> patch shouldn't change that. If it does then there's something 
> else wrong, but I don't see any change in image display here. 
>
> --  Alan Third 

--
Logic is a science of the necessary laws of thought, without which 
no employment of the understanding and the reason takes place. -- 
Immanuel Kant, 1785  Rudolf Adamkovič <salutis@me.com> 
Studenohorská 25 84103 Bratislava Slovakia  [he/him]