Mastering SVG’s stroke-miterlimit Attribute | Style-Tricks

So, SVG has this stroke-miterlimit presentation attribute. You’ve in all probability seen it when exporting an SVG from a graphic editor program, or maybe you discover out you might take away it with out noticing any change to the visible look.

After a very good quantity of analysis, one of many first issues I found is that the attribute works alongside stroke-linejoin, and I’ll present you ways in addition to a bunch of different issues I discovered about this fascinating (and probably missed) SVG attribute.


stroke-miterlimit will depend on stroke-linejoin: if we use spherical or bevel for joins, then there’s no have to declare stroke-miterlimit. But when we use miter as a substitute, we will nonetheless delete it and perhaps the default worth can be sufficient. Beware that many graphic software program editors will add this attribute even when just isn’t crucial.

What’s stroke-linejoin?

I do know, we’re truly right here to speak about stroke-miterlimit, however I need to begin with stroke-linejoin due to how tightly they work collectively. That is the definition for stroke-linejoin pulled straight from the SVG Working Group (SVGWG):

stroke-linejoin specifies the form for use on the corners of paths or fundamental shapes when they’re stroked.

This implies we will outline how the nook appears to be like when two strains meet at some extent. And this attribute accepts 5 potential values, although two of them have no browser implementation and are identified by the spec as at risk of being dropped. So, I’ll briefly current the three supported values the attribute accepts.

miter is the default worth and it simply so occurs to be a very powerful one of many three we’re . If we don’t explicitly declare stroke-linejoin within the SVG code, then miter is used to form the nook of a path. We all know a be part of is about to miter when each edges meet at a pointy angle.

However we will additionally select spherical which softens the perimeters with — you guessed it — rounded corners.

The bevel worth, in the meantime, produces a flat edge that form of appears to be like like a cropped nook.

What’s stroke-miterlimit?

OK, now that we all know what stroke-linejoin is, let’s get again to the subject at hand and choose aside the definition of stroke-miterlimit from the e-book Using SVG with CSS3 and HTML5:

[…] on actually tight corners, you need to lengthen the stroke for fairly a distance, earlier than the 2 edges meet. For that cause, there’s a secondary property: stroke-miterlimit. It defines how far you possibly can lengthen the purpose when making a miter nook.

In different phrases, stroke-miterlimit units how far the stroke of the perimeters goes earlier than they’ll meet at some extent. And solely when the stroke-linejoin is miter.

Miter join with miter limit in grey.

So, the stroke-miterlimit worth might be any constructive integer, the place 4 is the default worth. The upper the worth, the additional the nook form is allowed to go.

How they work collectively

You in all probability have a very good conceptual understanding now of how stroke-linejoin and stroke-miterlimit work collectively. However relying on the stroke-miterlimit worth, you may get some seemingly quirky outcomes.

Living proof: if stroke-linejoin is about to miter, it might probably truly wind up trying just like the bevel worth as a substitute when the miter restrict is simply too low. Here’s the spec again to assist us perceive why:

If the miter size divided by the stroke width exceeds the stroke-miterlimit then [the miter value] is transformed to a bevel.

So, mathematically let’s imagine that this:

[miter length] / [stroke width] > [stroke-miterlimit] = miter
[miter length] / [stroke width] < [stroke-miterlimit] = bevel

That is smart, proper? If the miter is unable to exceed the width of the stroke, then it should be a flat edge. In any other case, the miter can develop and type some extent.

Typically seeing is believing, so right here’s Ana Tudor with a beautiful demo displaying how the stroke-miterlimit worth impacts an SVG’s stroke-linejoin:

Setting miter limits in design apps

Do you know that miter joins and limits can be found in lots of the design apps we use in our on a regular basis work? Right here’s the place to search out them in Illustrator, Figma, and Inkscape.

Setting miter limits in Adobe Illustrator

Illustrator has a option to modify the miter worth when configuring a path’s stroke. Yow will discover it within the “Stroke” settings on a path. Discover how — true to the spec — we’re solely capable of set a worth for the “Restrict” when the trail’s “Nook” is about to “Miter Be a part of”.

Applying stroke-miterlimit in Adobe Illustrator.

One nuance is that Illustrator has a default miter restrict of 10 moderately than the default 4. I’ve observed this each time I export the SVG file or copy and paste the ensuing SVG code. That may very well be complicated whenever you open up the code as a result of even when you don’t change the miter restrict worth, Illustrator provides stroke-miterlimit="10" the place you may anticipate 4 or maybe no stroke-miterlimit in any respect.

And that’s true even when we select a special stroke-linejoin worth apart from “Miter Be a part of”. Right here is the code I obtained when exporting an SVG with stroke-linejoin="spherical".

<svg viewBox="0 0 16 10"><path stroke-width="2" stroke-linejoin="spherical" stroke-miterlimit="10" d="M0 1h15.8S4.8 5.5 2 9.5" fill="none" stroke="#000"/></svg>

The stroke-miterlimit shouldn’t be there because it solely works with stroke-linejoin="miter". Listed here are a few workarounds for that:

  • Set the “Restrict” worth to 4, as it’s the default in SVG and is the one worth that doesn’t seem within the code.
  • Use the “Export As” or “Export for Display” choices as a substitute of “Save As” or copy-pasting the vectors straight.

Should you’d prefer to see that mounted, be part of me and upvote the request to make it happen.

Setting miter limits in Figma

Miter joins and limits are barely totally different in Figma. After we click on the node of an angle on a form, underneath the three dots of the Stroke part, we will discover a place to set the be part of of a nook. The choice “Miter angle” seems by default, however solely when the be part of is about to miter:

Applying stroke-miterlimit in Figma.

This half works is much like Illustrator besides for the way Figma permits us to set the miter angle in diploma models as a substitute of decimal values. There are another particular nuances to level out:

  • The angle is 7.17° by default and there’s no option to set a decrease worth. When exporting the SVG, that worth is turns into stroke-miterlimit="16‘ within the markup, which is totally different from each the SVG spec and the Illustrator default.
  • The max worth is 180°, and when drawing with this feature, the be part of is mechanically switched to bevel.
  • When exporting with bevel be part of, the stroke-miterlimit is there within the code, but it surely retains the worth that was set when the miter angle was final energetic (Illustrator does the identical factor).
  • When exporting the SVG with a spherical be part of, the trail is expanded and we now not have a stroke, however a path with a fill colour.

I used to be unable to discover a option to keep away from the additional code that leads to the exported SVG when stroke-miterlimit is unneeded.

Setting miter limits in Inkscape

Inkscape works precisely the best way I’d anticipate a design app to handle miter joins and limits. When deciding on a a miter be part of, the default worth is 4, precisely what it’s within the spec. Higher but, stroke-miterlimit is excluded from the exported SVG code when it’s the default worth!

Applying stroke-miterlimit in Inkscape.

Nonetheless, if we export any path with bevel or spherical after the restrict was modified, the stroke-miterlimit can be again within the code, until we preserve the 4 models of the default within the Restrict field. Similar trick as Illustrator.

These examples will work properly if we select the Save AsOptimized SVG choice. Inkscape is free and open supply and, on the finish of the day, has the smartest code so far as stroke-miterlimit goes and the various choices to optimize the code for exporting.

However in case you are extra accustomed to Illustrator (like I’m), there’s a workaround to remember. Figma, due to the diploma models and the growth of the strokes, feels just like the extra distant from the specs and anticipated habits.

Wrapping up

And that’s what I discovered about SVG’s stroke-miterlimit attribute. It’s one other a kind of easy-to-overlook issues we would discover ourselves blindly reducing out, significantly when optimizing an SVG file. So, now when you end up setting stroke-miterlimit you’ll know what it does, the way it works alongside stroke-linejoin, and why the heck you may get a beveled be part of when setting a miter restrict worth.

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