Scaling SVG Elements

https://wattenberger.com/guide/scaling-svg

by wattenberger • 7 years ago

120 36 7 years ago

wattenberger.com

svnpenn2• 7 years ago

Dont use site

Moving those sliders will nuke your CPU

probably because the entire <body> is essentially just:

    <script src="/prism.js"></script>
    <script src="/static/js/20.c80b9d97.chunk.js"></script>
    <script src="/static/js/main.635019b5.chunk.js"></script>
    <script src="https://d3js.org/d3.v5.min.js"></script>
    <script src="https://d3js.org/d3-array.v2.min.js"></script>

fastbeef• 7 years ago

My 2015 Thinkpad with an i5 got 12% utilitaztion?

svnpenn2• 7 years ago

Yeah, on an 8 core thats 100% utilization of one of the cores...

devwastaken• 7 years ago

Works fine on Android Firefox. They should put in a debounce function on the sliders so it doesn't update as it's moving.

valine• 7 years ago

That would undermine the purpose of the site which is to help build an intuitive understanding of the svg viewport. There is educational value in having the graphic update while the slider moves.

40four• 7 years ago

I also experienced performance issues when using the sliders. My whole computer acted like it was going to freeze (Firefox/ Windows)

AceJohnny2• 7 years ago

No problem and smooth as butter in Firefox Windows.

cjfd• 7 years ago

Also works just fine with me. Firefox on linux here.

oneeyedpigeon• 7 years ago

Works fine on my ageing iPad mini. What was it about those 5 scripts that you thought would cause a problem? What machine/browser are you using?

wizzwizz4• 7 years ago

I don't like the architecture either, but this is one of the better sites using it that I've seen. It ran more smoothly than most non-interactive news sites, and the CPU usage was pretty much zero except when I was interacting with it.

What about your setup do you think might be causing this problem, given that very few other people are experiencing it?

adamch2• 7 years ago

Strange. I'm on a Macbook and this page nukes my CPU on FF Nightly, but not on Chrome.

Nullabillity• 7 years ago

Works fine for me on FF/Linux.

bryanrasmussen• 7 years ago

FF Developer 71.0b10 MacBook Pro from mid 2018 running Mojave, works great.

irrational• 7 years ago

Hmm, I didn't notice anything on Firefox on my Mac. I have a ton of tabs open and about and 15 programs running, including handbrake rendering some videos. I opened up Activity Monitor and watched what happened while loading and then manipulating the sliders. Nothing. Absolutely nothing budged under CPU, GPU, or Memory. The site was smooth as a hot knife through butter.

Maybe you should list your OS, your browser, and your hardware specs.

tyingq• 7 years ago

It runs fine on my crap Motorola Android. So, something is afoot with GPs device.

Mikhail_Edoshin• 7 years ago

Same problem here, had to restart the browser (Firefox/Windows). Ate all memory.

wattenberger4• 7 years ago

ah, the joys of frontend web development!

I added a 30ms debounce, just to help out a bit. I'm seeing some serious jank in Firefox, which smells like the beginning of a rabbit hole. Hopefully I'll find some time to dig in there.

akersten• 7 years ago

Cool visualization! Any plans to do more examples of SVG? There's lots of functionality in the format and it would be neat to see it documented in an interactive style like this.

wattenberger4• 7 years ago

I totally agree! I'm planning a video course on SVG, since there really aren't many good resources on it and I find it really powerful, and also fun!

Zaskoda2• 7 years ago

I'm current using Vue to manipulate a complex SVG as the foundation of my current game engine. It's not super snappy but it's effective and interesting. I've taken the concept pretty far and, thus far, I haven't see anyone else manipulating SVGs with Vue (or React or whatever) in this way before. Its surprising because it feels extremely intuitive.

planteen• 7 years ago

I've worked with hardware accelerated vector graphics engines (2D GPUs). It sounds like a good idea to do everything vector, because some things are very simple while retaining quality as you said. But in my experience, the vector operations are so expensive compared to raster ones that you go back to rasters to maintain framerate.

Zaskoda2• 7 years ago

Yes, even my relatively simple scenes are expensive to render. I'm hoping I can optimize it enough to be playable.

An interesting plus side: I can export the SVG as a file and get an extremely high quality screenshot.

IshKebab• 7 years ago

I haven't see anyone else manipulating SVGs with Vue (or React or whatever) in this way before. Its surprising because it feels extremely intuitive.

It's not surprising because it's extremely slow! If you're doing a 2D game, Canvas will be waaaay faster and is much more appropriate.

hombre_fatal• 7 years ago

I also use SVG from Elm for my simple games. Zoom and click-and-drag translation (and things like parallax) become trivial. And I love how you can put event listeners directly on objects.

Perfect for, e.g. board games!

PetahNZ• 7 years ago

I work with svg a lot, mostly with angularjs but also some vue recently. I have also made games with svg https://js13kgames.com/entries/spacetime

onion2k• 7 years ago

I'm working on an app for a startup to build diagrams using SVG and React (...lots of ForeignObject elements to embed HTML forms in the SVGs, bezier curves joining stuff together, etc). It's a really nice way of building a responsive 2D diagrammatic UI.

wattenberger4• 7 years ago

I really love creating things with SVG + React! I usually will use that until things start to jank up, and then switch to Canvas, which is more annoying for interactions and debugging.

You can get pretty far before that happens - for example, here's a post representing every country in SVG. https://wattenberger.com/blog/d3#maps-and-globes

adamch2• 7 years ago

This is a really beautiful way to demo this feature. Thanks!

kjhughes2• 7 years ago

For a constant height, why do width values between 0 and 100 cause (x axis) displacement, but width values above 100 cause scale reduction in both dimensions?

(A similar phenomena can be observed for a constant width while varying the height values.)

wattenberger4• 7 years ago

Good question! I'm trying to find a good way to explain this bit in the guide.

This is due to the preserveAspectRatio property on the svg element. Its default value is `meet`, which scales the svg with three rules:

- aspect ratio is preserved - the entire viewBox is visible within the viewport - the viewBox is scaled up as much as possible, while still meeting the other criteria

https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/p...

If you fiddle with the attribute value in the Dev Tools, try setting it to `xMinYMid` or `none` to see if that gives you a good sense of how it works. I'm worried that it might just confuse if not explained well :)

kjhughes2• 7 years ago

Thank you for the explanation (and for the cool visualization, btw).

It seems that preserveAspectRatio is an important part of understanding viewBox. IMO, it deserves a spot on the telescope's controls. I think a value of `none` might be the best starting point; all of the settings that result in combined scaling and displacement are less intuitive and likely harder to understand at first exposure.

Aside: Even if you decide to keep `xMidYMid ` as the default value for preserveAspectRatio, it seems that you ought to list it explicitly if you wish to specify a meetOrSlice value as Chrome is currently complaining with your existing preserveAspectRatio="meet":

  react-dom.production.min.js:978 Error: <svg> attribute preserveAspectRatio: Unrecognized enumerated value, "meet".

Scaling SVG Elements

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