Subject: Re: bug#64809: 29.1; Initial frame is wrong size when dimensions specified in init file

From: Jim Porter <[email-masked]>
Date: Mon, 24 Jul 2023 13:53:07 -0700

On 7/24/2023 9:33 AM, Jim Porter wrote:
> I found a related issue that might make this easier to diagnose: when I 
> run the following in Emacs 28.2, it correctly sets the default face 
> height for the current frame. With Emacs 29.1, it flashes for a second 
> at the correct size, then reverts to the default:
> 
> emacs -Q --eval "(set-face-attribute 'default (selected-frame) :height 70)"

At least for this case, I narrowed the regression down to the following 
commit:

   commit 52d4c98cec0901ef5cc1c55d5b3b33ac9d9c519f
   Author: Vincent Bernat <[email-masked]>
   Date:   Tue Oct 25 23:02:16 2022 +0200

       Fix detection of DPI changes in builds without Xft

       * src/xsettings.c (apply_xft_settings) [!HAVE_XFT]: Support
       XSETTINGS changes in non-XFT builds.  (Bug#43128)

So maybe the DPI detection in this commit is happening too late, or the 
code should bail out if the user has already customized the default face 
height?