bug#14567: Scrolling of large images

[Thomas Wiecki]

1. Download a large image (e.g. http://cdn.urbanislandz.com/wp-content/uploads/2011/10/MMSposter-large.jpg) and save it as /tmp/test.jpg

2. In an emacs buffer type "(insert-image (create-image "/tmp/test.jpg"))"

3. Type some arbitrary lines of text below this line.

4. In first line (containing insert-image), type C-x C-e at end of line to load the image.

5. Image should appear in buffer.

6. Scroll down repeatedly until past the image.

Expected behavior: Scrolls down smoothly even once scrolled past image.

Observed behavior: Scrolls down smoothly until end of image is reached. At end of image, the next scroll causes a huge jump in the window so that and only the text is shown but not any of the residual image.

7. scroll back up

Expected behavior: Scrolls upwards over image.

Observed behavior: Jumps over complete image and shows beginning of buffer.

Please let me know if there is anything else you need.

Thanks,

Thomas

On Thu, Jun 6, 2013 at 12:42 PM, Eli Zaretskii <eliz@gnu.org> wrote:

> From: Thomas Wiecki <thomas.wiecki@gmail.com>
> Date: Thu, 6 Jun 2013 08:17:02 -0400
>
> The scrolling behavior of emacs when there are large images (larger than
> the window height) in the buffer seems to broken. Specifically, down-ward
> scrolling makes a huge jump over the image as the image is about to move
> outside of the current view (it seems the image is treated as a single
> line).
>
> image-mode is not applicable as there is text intermixed with images.
>
> This behavior and its implications are also discussed here:
> https://github.com/tkf/emacs-ipython-notebook/issues/94
> and here:
> http://www.randomsample.de/dru5/node/25
>
> "slice-images" is a work-around solution but far from ideal.
>
> Any chance this could get fixed?

Any chance to get a simple reproducible recipe, complete with images,
which I could use to look into the problem locally?

Thanks.