bug#14233: 24.3; Don't constrain frame size to character multiples

[martin rudalics]

>>  > I would not like to see this behavior change, so that,
>>  > e.g., Emacs stopped resizing the frame when I change the
>>  > font size for the frame.
>>
>> It depends on the interface you use.
>
> Already that does not sound very good.  Why should the behavior be different
> depending on how you change a frame parameter?
>
>> The function `set-frame-font' has the KEEP-SIZE argument
>> and I don't intend to change its semantics (I'll probably
>> remove the rounding when `frame-resize-pixelwise' is non-nil).
>
> I use `modify-frame-parameters', providing a new value for parameter `font'.

Conceptually, `modify-frame-parameters' allows to change several frame
parameters for the next redisplay.  But the outcome depends on the
evaluation order of the ALIST argument.  Suppose you want to change a
frame's font and size in one and the same call.  The result would depend
on which element is evaluated first due to the fact that changing the
font allows to change the size of the frame too.  This is not my idea of
clean semantics.

> The new value is calculated this way (in frame-cmds.el):
[...]
>     (modify-frame-parameters frame (list (cons 'font fontname)))

I suppose it would be trivial to change this single line to use
`set-frame-font' in order to deal with the change I propose.  But if
people like the current behavior I can obviously leave things as they
are now.

martin