[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
bug#68006: 30.0.50; Image-mode speed
From: |
Manuel Giraud |
Subject: |
bug#68006: 30.0.50; Image-mode speed |
Date: |
Mon, 01 Jan 2024 11:10:33 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) |
Stefan Kangas <stefankangas@gmail.com> writes:
> Manuel Giraud via "Bug reports for GNU Emacs, the Swiss army knife of
> text editors" <bug-gnu-emacs@gnu.org> writes:
>
>> And here is a new version of the patch. Maybe, we need a NEWS entry for
>> this too.
>
> If we have an option, then yes we should add it to NEWS too.
>
> But I'm not sure about this one:
>
> Flushing the image cache all the time is fine for images that are 4KB in
> size, but these days we routinely work with images that are several
> megabytes in size (to give an idea, searching online tells me that
> Twitter allows uploading photos up to 2 MB, Facebook up to 15 MB).
Hi Stefan,
First, I want to say that here we're just talking about image-mode (and
its derivatives like docview) and how the image cache is managed in this
mode only.
"Flushing the image cache all the time" is what is done *now* in
image-mode. In fact, this new option permits to inhibit it.
> Furthermore, my experience with image-dired has taught me that Emacs is
> terribly slow when compared to all other programs capable of viewing
> images out there. So I think we should think a bit more about this
> one.
Yes and this slowness was what I wanted to speed up in the first place
in image-mode: moving from one image to the next is slower than any
other program. I know that working on the image cache is picking a
low-hanging fruit here but I'm not an expert in fast image processing.
> Taking a step back, why are images treated differently from other
> buffers? If the risk is that the image changes on disk without us
> noticing, then users should need to either run `revert-buffer' or enable
> `auto-revert-mode'. If we are talking about images that are inline in a
> buffer, the cache should be flushed only when the buffer itself is
> reverted. What am I missing?
I guess that makes sense but would it be easy to plug the
'revert-buffer' machinery into the image cache internals? I don't know.
> Lastly, I'm not sure about the "hash the first 4 KB of an image"
> heuristic, for starters because images can be several megabytes in size.
> Would it not be both more accurate and faster to check the mtime and/or
> the size of the file? Or do we need different heuristic for different
> image formats? (Maybe JPEG changes the first 4 KB on save, but I don't
> think all bitmap formats do.) But wouldn't it be even better to use the
> notify system when possible, like with `auto-revert-use-notify'?
You're right that this heuristic might not be the best one. I
repurposed it from image-dired when Eli suggested something content
based. Maybe we could have a modification time of the image into its
spec and compare it to said image file before display.
Best regards,
--
Manuel Giraud
- bug#68006: 30.0.50; Image-mode speed,
Manuel Giraud <=
- bug#68006: 30.0.50; Image-mode speed, Stefan Kangas, 2024/01/01
- bug#68006: 30.0.50; Image-mode speed, Manuel Giraud, 2024/01/02
- bug#68006: 30.0.50; Image-mode speed, Eli Zaretskii, 2024/01/02
- bug#68006: 30.0.50; Image-mode speed, Manuel Giraud, 2024/01/02
- bug#68006: 30.0.50; Image-mode speed, Eli Zaretskii, 2024/01/02
- bug#68006: 30.0.50; Image-mode speed, Manuel Giraud, 2024/01/04
- bug#68006: 30.0.50; Image-mode speed, Eli Zaretskii, 2024/01/04
- bug#68006: 30.0.50; Image-mode speed, Manuel Giraud, 2024/01/04
- bug#68006: 30.0.50; Image-mode speed, Eli Zaretskii, 2024/01/04
- bug#68006: 30.0.50; Image-mode speed, Manuel Giraud, 2024/01/04