Re: Child-frame can not move to proper position when run "env GDK_SCALE=2 emacs"

[Dmitry Gutov <dgutov@yandex.ru>]

On 1/9/18 1:06 PM, Robert Pluim wrote:

> Ugh. I don't think we should expose the scale values, we should fix
> whatever the issue is with set-frame-position. Naively that's the
> attached patch, but I worry about other places that assume unscaled
> coordinates. I'll run with it for a while and see if any pop up.

This seems to fix the immediate issue (company-mode popup based on child 
frames is now positioned correctly on my HiDPI screen). Would be great 
to get this one into Emacs 26.

> Longer term we need to implement your 'eliminate direct X calls' plan,
> and have everything inside Emacs use GTK coordinates.
> 
> Robert
> 
> diff --git i/src/xterm.c w/src/xterm.c
> index f771631daf..950e6231e0 100644
> --- i/src/xterm.c
> +++ w/src/xterm.c
> @@ -10311,6 +10311,14 @@ x_set_offset (struct frame *f, register int xoff, register int yoff, int change_
>   {
>     int modified_top, modified_left;
>   
> +#ifdef USE_GTK
> +  {
> +    int scale = xg_get_scale(f);
> +    xoff /= scale;
> +    yoff /= scale;
> +  }
> +#endif
> +
>     if (change_gravity > 0)
>       {
>         f->top_pos = yoff;
>