[PATCH v2 app/xrandr] Document that --dpi and --fbmm options set DPI of whole X screen

[Giuseppe Bilotta]

On Thu, Nov 2, 2017 at 6:20 PM, Pali Rohár <pali.rohar at gmail.com> wrote:
>
> But back to my documentation update patch. It is needed to rework it?
> And if yes, how,

In light of my opinion on the relevant of the core DPI value, here's
my take on it, chunk by chunk:

> -Sets the reported values for the physical size of the screen. Normally,
> +Sets the reported values for the physical size of the whole X screen (not particular
> +output!) which consists of all configured monitors. Physical size of the X screen does
> +not have any meaning when monitors with different DPI are configured. Normally,
>  xrandr resets the reported physical size values to keep the DPI constant.

How about something like this:

Sets the value reported as physical size of the X Screen as a whole
(union of all configured monitors).
In configurations with multiple monitors with different DPIs, the
value has no physical meaning, but it may
be used by some clients to compute a reference font scaling. Normally etc



> -This overrides that computation.
> +This overrides that computation. This option should be calculated from DPI
> +value 96 as it not have any useful meaning for multi-monitor configuration.

I would skip this change.



> -This also sets the reported physical size values of the screen, it uses either
> +This also sets the reported physical size values of the whole X screen (not particular
> +output!) which consists of all configured monitors. Physical size of the X screen does not
> +have any meaning when monitors with different DPI are configured. This option uses either

I would rewrite this to match the alternative I proposed for the first chunk.



> -physical size using whatever pixel size will be set.
> +physical size using whatever pixel size will be set (default 96 DPI). It does not
> +have any useful meaning for multi-monitor configuration.

I would skip this change. If we do want to give some suggested values,
it could be rewritten something like:

physcal size using whatever pixel size will be set. Typical values are
the default (96 DPI), the DPI of the only monitor in single-monitor
configurations, or the DPI of the primary monitor in multi-monitor
configurations.


-- 
Giuseppe "Oblomov" Bilotta