Fit to window height (kate-like behaviour)

[Evpok]

Posting this forgotten¹ comment as its own feature request.

Please, also consider an option to have a minimap auto-resized vertically, so it would eliminate a need to scroll it. This is how minimap works in Kate editor, and it makes the map a really fast tool for jumping between various places in large source files, despite it being less accurate that way.

To be clear: Kate's minimap is not scrollable. Instead, when the file is longer than the minimap allows, the character height (in minimap) is decreased to make the whole file fit vertically in the minimap. This way, the minimap is less precise but provides a better overview.

Of course it should be behind a setting, if not a module, but I don't know if the latter is possible short of monkey-patching a dynamic character height.

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¹ And rightfully so, since it was not in the right place.

[abe33]

Hi @Evpok, sorry for the late reply.

I think this feature was already suggested a while ago, I haven't the issue under the hand though. Having thought a bit about it I identified several major issues with this feature:

• one that actually make me really reluctant to start looking at an implementation, is that it would require to draw many many more lines than now. Drawing lines requires to fetch their tokens, which is already a costly operation (I hope the core team will continue improve this part in the future) but it can be reduced by a caching strategy at the canvas level. Given that each lines have the same height, and given that the amount of lines on screen at a single moment is almost constant (it varies by on when scrolling) it's really simple and effective to simply copy the part that didn't change from an offscreen buffer, which mean that updating the minimap while typing in the buffer generally only involve to redraw the edited lines. With that feature, the whole minimap will need to be repainted whenever lines are added or removed since the scale of lines will then change. That's if we want to keep the minimap canvas at the optimal size (the editor height) without playing with CSS transforms.
• CSS transforms could be a solution, the minimap canvases would have a variable height based on the changes in the editor's content length, it would allow us to preserve the premise that every lines we have to draw always have the same height. But there's two problem here:
  1. a memory problem, given that buffers can have any size, and that we have 3 canvases per minimap, I fear that we'll hit the canvas memory limit for huge buffers (and AFAIK it's not a constant we can anticipate)
  2. a rendering problem, canvas and CSS transforms doesn't play well, subpixel rendering being what it is, there's a high risk that the render gets ugly quickly the more lines there's to draw on the minimap. I tried quickly to scale a minimap and then scrolling to see how it played, and it quite weird:
     

That being said, it would be better to have a working proof of concept to gauge the cost and benefits of each strategy. I'll see if I can find some time to try the second approach. But if anyone want to give it a try I'm open to suggestion and of course PRs.

[zypA13510]

Hi, I was just looking for this settings. It's just a pity it is not implemented yet.

For me, the need of this enhancement comes from a completely different usage, which I believe it's not what minimap was originally planned for. However minimap is still the closest I can get. I don't need a overview of every character. I only want minimap to render base on lines, so that I can easily identify large code blocks, and navigate to the error/diff among them. (There are plugins for minimap which will highlight the entire line, like minimap-linter, or minimap-git-diff)

For now, my solution is, in settings, set

Absolute mode = true;
Adjust minimap only if smaller = true;
Adjust minimap width to soft wrap = false;

and then in the stylesheet, add:

atom-text-editor::shadow, atom-text-editor, html {
  atom-text-editor-minimap {
    &.absolute {
      width: 2%;
    }
  }
}

But due to the nature of fixed line height in minimap, it is not synchronized with the scroll bar. But it's so narrow now, I can hardly click on it to navigate. That's why I'm looking for this.

[Evpok]

Hi, thanks for such a detailed reply! I have to admit I know next to nothing of canvas, but why couldn't we still reuse the unchanged parts by rescaling them?

Also I fiddled with Kate a bit, and instead of applying the changes to them minimap in real time (like you do), it waits until typing stops, would that be sufficient to address the performance concerns? Though that may be too great a deviation from the original behaviour of this package.

[abe33]

I won't have much time to play around with that feature, but if anyone wants to give it a try and make a prof of concept, I'll be glad to take a look at it.