bug#66308: 30.0.50; DocView: Bump default value of doc-view-resolution

[Stefan Kangas]

Po Lu <luangruo@yahoo.com> writes:

> How about making the resolution commensurate with that of the display
> itself?  Monitor density has not increased for lay folk, only those
> willing to spend prodigally on display hardware.

Yes, if we can make it dynamic, that should be even better.

Do we have a canonical way of checking the resolution of the screen that
the current frame is on?

> Compounding that, larger images will consume greater quantities of disk
> space and X server memory.  Bear in mind that /tmp is customarily small;
> only 4 GiB on my system, with 1.8GiB in use, whereof /tmp/docview1000
> consumes 971 MiB.

That's an important consideration.  We have the `doc-view-clear-cache'
command, but perhaps we could do more, for example

a) a separate command to display the cache size, or
b) a warning when the cache size reaches some threshold, or
c) automatically cleaning up old files when the cache reaches some
   threshold,

or some combination of all of the above.