WEBVTT 00:00.000 --> 00:10.240 Fair while now, or alternatively have been kicking outside, so yeah, thanks for making 00:10.240 --> 00:16.760 the effort. I do appreciate that. Bit about me, so my name is James Milner. I'm a staff 00:16.760 --> 00:23.160 software engineer at a company called Nearform. I live in London, working remotely. Nearforms 00:23.160 --> 00:27.760 like a digital consultancy has a big history and opensource specifically in the kind of 00:27.760 --> 00:34.680 like Node.js ecosystem, and yeah, this is my territory as my personal project, but they're 00:34.680 --> 00:40.280 very supportive and they've helped me to come here today, so yeah, shout out to them. 00:40.280 --> 00:46.360 So, let's get started. What is territory? So, territory is an open source JavaScript 00:46.360 --> 00:52.760 library for drawing on web maps. So, the source is MIT license, and yeah, it's a JavaScript 00:52.760 --> 00:58.520 library, so it runs in the front end, in your browser, alongside your map, in your front end 00:58.520 --> 01:06.080 code, and it's for drawing on web maps. So, drawing is maybe a bit of a loaded term, or 01:06.080 --> 01:11.400 a loaded concept, so sometimes I think it just helps to have a tangible example to point 01:11.400 --> 01:17.800 to. So, the one that I give is, if in the UK, we have two companies, Zootpler, right 01:17.800 --> 01:23.480 move, they might also be present in other parts of Europe and beyond, but essentially 01:23.480 --> 01:28.880 their property search websites, so you can go to these websites, you can type in what 01:28.880 --> 01:34.120 you're looking for, you know, number of bedrooms or the location, and you can find places 01:34.120 --> 01:38.480 to buy or rent. And they also have a tool, both of them have a tool for allowing you to 01:38.480 --> 01:44.600 draw an area of interest on the map, and then only return Polygon, sorry, only return 01:44.600 --> 01:49.680 properties that exist within that Polygon or in that area of interest. So, that's the 01:49.680 --> 01:53.400 kind of thing that I'm talking about when I'm saying drawing on a web map, like Ditchery, 01:53.400 --> 01:59.720 the user, inputting, and drawing on the web map. And there's some prior art here, there's 01:59.720 --> 02:09.560 a few libraries that do this in varying degrees of functionality, and like how up to date, 02:09.560 --> 02:15.440 like how well maintained they are. The one that I was probably the most familiar with before 02:15.440 --> 02:24.840 starting to draw was MapboxGL Draw, which is for MapboxGL.js, a mapping library, and so 02:24.840 --> 02:30.840 in my previous role I was working on indoor mapping, indoor positioning, and we needed 02:30.840 --> 02:38.240 the way to basically create indoor maps, and so I was using MapboxGL Draw, and then after 02:38.240 --> 02:42.640 that company I kind of had some thoughts about like potentially like a different approach, 02:42.640 --> 02:47.680 or another way of kind of structuring like a drawing library, or things that I thought could 02:47.680 --> 02:56.000 potentially be worked on or improved on kind of the pire art. So, the kind of the goals 02:56.000 --> 03:04.240 of Tera Draw are that it's cross library support. So, kind of takes the approach of having 03:04.240 --> 03:08.640 like an adaptor pattern, so there's an adaptor for a bunch of different mapping libraries, 03:08.640 --> 03:14.320 which I'll come on to in more detail in a minute, but 90% of the code is in the core, and then 03:14.320 --> 03:20.640 these adaptors just are kind of like a little like an interstitial bit between the core 03:20.640 --> 03:26.800 territorial library and the mapping library. I wanted it to be customizable, so what I mean by that 03:26.800 --> 03:32.720 is you could create your own complex drawing modes, so people have all sorts of weird and 03:32.720 --> 03:38.240 wonderful requirements, and basically I wanted to be able to allow support for that, and similarly, 03:38.240 --> 03:44.640 if a new mapping library comes along, I wanted to be able to allow to create an adaptor for that 03:44.640 --> 03:50.880 fairly easily. So, yeah, just customizability and extensibility was kind of one of the initial goals. 03:52.080 --> 03:57.440 Keep styling, so basically being able to style every aspect of like the drawing experience, 03:58.160 --> 04:03.440 some of my previous experiences were like, you couldn't get a consistent look and feel, 04:03.440 --> 04:07.920 because you could only style like certain aspects of the drama trees that were being rendered, 04:09.200 --> 04:13.280 and so that was kind of like something that I wanted to support from the outset, 04:13.280 --> 04:18.800 was being able to style kind of everything that's going on in the kind of drawing experience. 04:19.360 --> 04:25.440 And then the last thing is, it was just kind of this approach of like not having any 04:26.320 --> 04:32.160 additional runtime dependencies, not necessarily saying that that's like a better or, you know, 04:32.160 --> 04:37.040 isn't a superior approach, but it was more just like historically I've worked on a lot of projects 04:37.040 --> 04:42.400 where just you try and build something or you try and instill something and something just breaks, 04:42.400 --> 04:47.920 because especially in the like kind of node ecosystem, there's a lot of just like, 04:47.920 --> 04:53.360 you can end up in dependency how, and so just taking that approach kind of simplifies that and 04:53.360 --> 05:04.080 reduces the possibility of having those kind of issues. So there's a bunch of different, 05:04.080 --> 05:09.760 as I was kind of saying, Torrodros supports a bunch of different mapping libraries out the box, 05:09.760 --> 05:16.800 so the the six that are supported in the kind of, I guess, core library of Torrodros. So open there's 05:17.360 --> 05:25.680 leaflet, map lever, jl, js, Google Maps, mapbox, jl, js, and js, maps SDK for JavaScript. 05:27.120 --> 05:32.720 So the top three are open source and the bottom three are like proprietary, but yeah, 05:32.720 --> 05:39.200 so they're support for these these mapping libraries out the box. And as I said, it's possible 05:39.200 --> 05:45.520 if you have your own custom map rendering library, then it should in theory be possible to write 05:45.520 --> 05:53.040 your own adapter, as long as you can fulfill some basic criteria for the like interface for that 05:53.040 --> 06:02.720 adapter. And so it's quite rare, but there are scenarios where that kind of decoupling can be quite 06:02.720 --> 06:08.480 helpful. So say for example, you are using a mapping library and the underpinning services that 06:08.480 --> 06:13.280 power it change their pricing model and it no longer becomes viable for you to, like financially, 06:13.280 --> 06:18.400 it's not possible for you to keep using that library. Having that decoupling can be quite useful. 06:18.400 --> 06:23.440 Similarly, if the license changes for the underlying library and that's no longer compatible with 06:23.440 --> 06:28.720 your business or like your project or whatever you're trying to do, then that is another reason 06:28.720 --> 06:33.280 why you might want to swap that out. And then the other, I guess, more obvious thing is that 06:34.080 --> 06:39.200 different mapping libraries have different limitations or different feature sets. And so if there's 06:39.200 --> 06:44.080 something you need to do and then you realize like two or three years into a project that you 06:44.080 --> 06:51.200 can't do that in that specific mapping library, then just having that decoupling can be potentially 06:51.200 --> 06:57.920 quite useful. So this is the architecture or the kind of a basic overview of the architecture 06:57.920 --> 07:01.840 of Taugeau. So as I was saying, we've kind of got this, these adapters which are the kind of the 07:01.840 --> 07:11.520 Stinlayer at the front. They take in inputs like user input from the user. That goes into 07:11.520 --> 07:15.920 the mode. So there's we have a bunch of different built-in modes for different geometry types. So 07:17.120 --> 07:23.840 point, polygon, line string, circle, rectangle, and then there's some more sort of exotic ones that 07:23.840 --> 07:29.920 I will come onto later. And so these are just the modes and that's contains all the logic for like 07:30.000 --> 07:37.200 handling, you know, drawing those geometry types. And then it's all just backed by what was just 07:37.200 --> 07:42.640 called a store, which is essentially where all the geojson geometries are stored and then retrieved 07:42.640 --> 07:49.520 or and then updated. So yeah, it's just kind of like this three-tier approach, which I think 07:49.520 --> 07:58.640 works quite nicely and kind of isolates things quite nicely. We, there's no runtime dependencies 07:58.640 --> 08:05.280 that we do rely on a bunch of other open source tools for a lot of the development time functionality. 08:05.280 --> 08:12.080 So it's the whole library is written more or less exclusively in TypeScript. I just like types and I 08:12.080 --> 08:16.160 think it's kind of become a maybe a bit of an industry standard on JavaScript projects now. 08:18.400 --> 08:22.880 We use just, which is potentially maybe going like a little bit of fashion. It's the tick testing 08:22.960 --> 08:29.600 library. But for me, it works and has been relatively popular and people understand how it works. 08:30.560 --> 08:36.240 So that was kind of the choice there. Webpack for local development. So there's like a local 08:36.240 --> 08:40.160 environment where you can just experiment with all the different drawing modes and all the different 08:43.280 --> 08:48.320 adapters locally if you just want to like change something and play around with things. Then 08:48.320 --> 08:54.160 that all is backed by like webpack just bundles at all and makes it all possible. And then lastly, 08:54.160 --> 08:59.360 use a thing called micro bundle, which is quite a niche project, but I find it really useful. It's just 08:59.360 --> 09:04.480 for like it does the actual, it creates the actual end bundle that gets put onto NPM, like the 09:04.480 --> 09:11.600 node package manager. But it just sorts out a lot of the complicated aspects of like delivering 09:12.320 --> 09:18.400 like a JavaScript package on NPM essentially. So that's why we use that. 09:20.800 --> 09:25.760 Let's have a little look at like how you can get started with Todoror. So the simplest thing 09:26.800 --> 09:33.600 probably is, well, if you have an existing project, you can use NPM to install Todoror into your project 09:34.400 --> 09:39.440 just NPM install Todoror. You also need an adaptor, which will be like a separate package, 09:39.440 --> 09:44.320 which I'll show you how you install those different adapters later on, but the core library is just 09:44.320 --> 09:51.040 Todoror, or you can use yarn or like other node JavaScript package managers if you want, 09:51.040 --> 09:57.920 does you know, whichever one you're using is fine. The actual project is available at my 09:57.920 --> 10:04.640 GitHub handle, which is James Elmone, a four-slash Todoror. There's docs in there, there's API documentation, 10:05.280 --> 10:11.920 the whole project basically lives in there. And then lastly, there's websites, just Todoror.io. 10:12.960 --> 10:20.000 Looks a little something like this, but it's essentially quite similar to, if you've ever used 10:20.000 --> 10:27.120 GiaJson.io, kind of a fairly comparable sort of set of functionality, but helps just demonstrate 10:28.000 --> 10:37.520 how Todoror would work in like an end project. So at the top is like the bunch, the different modes, 10:37.520 --> 10:43.440 and then the geometries that you're seeing on the screen are the output of like using those modes. 10:43.440 --> 10:48.080 There's also some other modes that we a bit more like are saying a bit more exotic, that aren't 10:48.080 --> 10:53.600 like on here that will come onto later, but it's just showing you the basic functionality of like 10:53.600 --> 10:58.240 point line polygon. We have like a free hand mode if you want to draw like a free hand polygon. 10:59.760 --> 11:04.080 Yeah, so that's, and that's just something you can just, if you just want to get a high level 11:04.080 --> 11:08.720 sense of like what Todoror does, you can just go on that website and just play around with it. 11:12.800 --> 11:20.400 And then at like a code level, this is just an example using map Libra. So lines one to six, 11:20.400 --> 11:29.440 we're just instantiating a map Libra map, give it like a center, some styling, give it a specific zoom 11:29.440 --> 11:36.240 level, that instantiates the map. And then once that's finished loading, then we can instantiate Todoror. 11:36.240 --> 11:42.160 So we start a new Todoror instance, we give it an adaptor in this case the map Libra adaptor, 11:43.200 --> 11:47.520 and then we just give it an array of all the modes that we want to instantiate with. So in this case 11:47.680 --> 11:54.160 on line 11, we just instantiate like just to keep things simple, simple, we just instantiate 11:54.160 --> 12:00.960 polygon mode. And that will, in this case, we just have snapping, which is like a piece of functionality 12:00.960 --> 12:06.080 that we support, so you know, snapping to whilst you're drawing, snapping to other polygon 12:06.080 --> 12:13.120 vertices that you've drawn. And then the end we just start the whole instance and that kicks everything 12:13.840 --> 12:22.800 off. That's like a simplified version of what that looks like, but it's hard to, you know, 12:22.800 --> 12:30.720 fit too much code on one slide, so hopefully you'll forgive me. So the project's been going for 12:30.720 --> 12:36.480 about two and just over two and a half years, and all of that time it's kind of been in alpha 12:37.200 --> 12:41.920 and then beta. It's kind of just for a long time like tinkering with a lot of stuff and just trying 12:42.800 --> 12:48.400 to get things right. So this month we finally just released like a version one and that kind of 12:48.400 --> 12:55.920 like solidifies the foundation for the kind of the future of the project and hopefully like give some 12:55.920 --> 13:02.560 signal to other people that it's like you can rely on it to some extent to in your projects. 13:03.200 --> 13:12.400 And so like one of the big changes in version one is essentially previously all the adapters 13:12.400 --> 13:19.040 were like baked into the core territorial module or the core territorial package sorry. 13:21.040 --> 13:26.480 But that has like some that was essentially causing issues for certain people things like 13:27.280 --> 13:33.600 um type script types or like missing for like somebody would be using I don't know if the 13:33.600 --> 13:38.080 leaflet adapter and they'd be getting complaints about like missing type script types for like the open 13:38.080 --> 13:43.920 layers adapter and it's like well that person doesn't care about open layers like they shouldn't 13:43.920 --> 13:48.400 have to, right? So it's basically like the thought process was just to basically terrible with that 13:48.400 --> 13:54.880 out and then just have a module per adapter. And so now you just install the adapter with the 13:54.880 --> 13:58.960 map library that you're using and then you install the territorial on side that and then you can just 13:58.960 --> 14:07.600 use those those two together um yeah it also just helps like in or enforce like decoupling between 14:07.600 --> 14:16.960 the adapters and territorial itself um which is a nice side effect I think um the other thing was like 14:16.960 --> 14:21.760 I was saying earlier about this kind of a bit more like exotic mode can I use this laser yes I can 14:22.400 --> 14:28.480 um and so there's a few extra modes that have just come in and like recently so one of them is 14:28.480 --> 14:33.840 uh this is set to mode which is a bit like allows you to draw like a sector of a circle basically like 14:33.840 --> 14:40.640 like you know a control like a semi circle um and then also sense mode which is similar like 14:40.640 --> 14:47.520 kind of the same premise but like a doughnut so you control like a doughnut essentially um and these 14:47.600 --> 14:55.440 two are kind of actually requested on the basis of like um this was for like uh there's uh one of 14:55.440 --> 14:59.760 the guys who's using the project are like mountain rescue and one of the things that they do is like 14:59.760 --> 15:06.560 they want to know they have like various uh CCTV cameras that have like certain field of view like 15:07.120 --> 15:12.400 vision and so basically they can draw out and say like the field of view of a given camera 15:13.040 --> 15:19.760 in the in the mountains basically um and so this basically helps the map out so it sounds quite 15:19.760 --> 15:23.200 niche and like why would you have any of that but so I just wanted to kind of try and give some reasoning 15:23.200 --> 15:28.000 whether um so they use it for that essentially which is quite cool and the last one is uh 15:29.200 --> 15:33.680 those are the diamond bits actually we call this like angled rectangle mode so tarot draw for long 15:33.680 --> 15:41.360 time has had like a rectangle mode where you can draw a rectangle but it's always oriented from like 15:41.440 --> 15:46.800 north um like because the map is generally oriented north unless you've like rotated it or something 15:48.080 --> 15:55.120 and so angled rectangle mode just allows you to draw like a rectangle or any like arbitrary 15:55.120 --> 16:00.480 orientation essentially um so that's just like another mode that there's kind of now baked into 16:00.480 --> 16:06.400 total and yeah as we're saying like there's also opportunity to build your own custom modes if you 16:06.400 --> 16:12.400 want to do kind of weird and wacky things so I've built some modes for like doing um 16:13.440 --> 16:19.680 client side routing so if you have like a complex so you could use if for example the example I 16:19.680 --> 16:26.400 had was like basically just converted a bunch of OSN roads data into geojson and then was basically 16:26.400 --> 16:32.240 just doing like clients allowing you to draw out client side roots using tarot draw as like a 16:32.240 --> 16:40.800 kind of custom mode and then another example was like using the um there's a there's a model 16:40.800 --> 16:46.800 called like segment anything model which like matter released which is can basically like pull out 16:47.360 --> 16:52.080 features essentially from like an image and so then using that to like being able to like pull out 16:52.080 --> 16:56.000 you could click on a building and it would generate the like polygon for the building essentially 16:56.640 --> 17:03.600 again it's like a kind of custom mode integral um so yeah that's uh new modes and then at custom modes 17:06.480 --> 17:15.280 also some like uh new kind of additions to uh configuration of existing modes that were potentially 17:15.280 --> 17:19.760 quite interesting so one of them is like called like validation and so validation is basically 17:20.320 --> 17:27.920 sometimes you want to prohibit users from creating polygons or points or like any kind of geometry 17:27.920 --> 17:35.920 that doesn't add here to some sort of like uh like validity rules or best practice or whatever it 17:35.920 --> 17:40.320 might be so in this case it's about like you don't want to have a polygon that's self intersecting 17:41.040 --> 17:47.040 there's various reasons why you probably wouldn't want self intersecting polygons in your like 17:47.040 --> 17:52.400 database or whatever it might be um but you can actually like this is just free form so you could 17:52.400 --> 17:58.480 essentially just do anything in here and this just allows you to prevent creating data that you feel is 18:00.160 --> 18:07.040 invalid essentially um and then the next one is about like snapping so 18:07.040 --> 18:11.360 total support is snapping for a little while but there's kind of been some improvements to 18:11.680 --> 18:17.280 um kind of how that works so like one of the nice things is you've always been able to snap to 18:17.920 --> 18:25.760 the um coordinates of a polygon so like the vertices of a polygon so for example like 18:25.760 --> 18:32.080 basically the corners here um but now we also just support snapping to like an arbitrary 18:32.640 --> 18:37.840 place on any of the lines of the polygon as well um so for example here this is just snap to like 18:38.720 --> 18:44.880 somewhere along this line here essentially um and so a lot of people find that useful um so 18:45.840 --> 18:53.920 that's something that we added support for um the other thing that we've kind of been working on 18:54.400 --> 18:59.200 it's it's tricky I wouldn't say it's perfect but it's at least kind of like the foundation for 18:59.280 --> 19:06.080 supporting like drawing on essentially like globes um which basically just requires you to um 19:08.240 --> 19:12.320 like when you're drawing on a web Macator map and you draw a square or a circle or whatever it 19:12.320 --> 19:19.920 might be when you actually place that on a globe because like you if you yeah it's this 19:20.960 --> 19:25.840 you end up with a scenario where like it's no longer circular it's no longer rectangular because when 19:25.920 --> 19:31.360 you project like something that's been drawn on a 2D web Macator map onto a globe it loses the 19:31.360 --> 19:36.400 property of being circular or a rectangular and vice versa if you draw a circle on a globe 19:36.400 --> 19:43.040 and you project it down onto a map it's going to look like more like an oval basically um and so 19:43.040 --> 19:52.560 now tarot draw has basic support in its modes for um drawing on on globe essentially but yeah 19:52.640 --> 20:01.200 it's not perfect but we're working on it community um so we've been really lucky to have like quite a few 20:01.200 --> 20:08.720 people uh getting involved so we've had 24 unique contributors over the last two and a half years 20:09.840 --> 20:16.000 there's 48 this is just some data I just pulled out of like GitHub insights but there's 48 20:16.880 --> 20:23.600 repositories that depending on it um 590 stars yeah obviously it's a bit of a vanity metric but 20:23.600 --> 20:28.800 it's just always nice to see people taking an interest in something you're working on and similarly 20:28.800 --> 20:36.000 64 forks again just nice to see people checking out the code um but yeah if you want to get involved 20:37.200 --> 20:44.000 appreciate like any feedback you might have either on this talk or the um on any of the functionality 20:44.080 --> 20:49.920 of tarot draw itself I feel free to just you know you can kind of speak to me afterwards um or 20:51.360 --> 20:56.000 yeah feel free to write an issue on GitHub if you find bugs or you find there's a feature that you 20:56.000 --> 21:01.280 feel is missing um yeah feel free to share it if you know people that might benefit from using 21:01.280 --> 21:08.400 the project and yeah obviously we always welcome contributors um to tarot draw itself so please 21:08.400 --> 21:13.760 feel free to check out the code um start hacking around and if there's something that you feel 21:13.760 --> 21:24.400 like you could fix then I've just encouraged you to have a go um yeah I think that's me thanks 21:32.400 --> 21:34.400 questions 21:35.360 --> 21:56.000 yeah at the moment it only supports um 2D and well there's multiple reasons for that one of 21:56.000 --> 22:01.440 which is the GIAs and specification only supports two dimensional data by default I think 22:01.760 --> 22:08.800 um so it would be because it all backed the like the whole store concept is like everything is stored 22:08.800 --> 22:15.200 in GIAs and like everything is exported in GIAs and so you'd have to come up with a way to like 22:15.200 --> 22:23.520 represent that data but that kind of third what is said coordinate it's like you can't do that without 22:23.520 --> 22:28.080 breaking the GIAs and specification really and so you'd have to come up with it like it could be 22:28.080 --> 22:33.440 plot like you could add it as like a property in the property like basically as metadata like that 22:33.440 --> 22:40.400 said property but um yeah by default it doesn't support like three dimensional drawing out the box 22:40.400 --> 23:01.440 yeah so the question was um do you plan on adding support for translating rotating scaling um 23:01.440 --> 23:05.920 so it does actually we do it does actually have support I didn't show it but we do actually have 23:06.000 --> 23:11.920 support for so there's one of the modes is select mode and you can select polygon and then you can then 23:11.920 --> 23:19.200 you can modify all the coordinates but you can also do scaling, rotating and just move like 23:19.200 --> 23:24.720 translation like just moving as well so it does support it but you have to enter like a select mode 23:24.720 --> 23:30.000 select the polygon and then start playing it so yeah thanks there's a great question 23:30.080 --> 23:48.480 yeah sure yeah yeah no it's a good question so the question is do does tarot draw 23:48.480 --> 23:54.400 do the rendering or is it kind of um does it offload it to the mapping library to render the actual 23:54.720 --> 24:01.440 data so yeah as I'm saying all the data is in um geojson and so essentially what happens is 24:01.440 --> 24:10.000 is each of the adapters has a way to render geojson data via the underlying library so if you use 24:10.000 --> 24:17.680 like leaflet it will use the leaflet method for like rendering geojson um so yeah it's offloaded 24:17.680 --> 24:22.720 to the the library itself like we don't overlay like a web jail canvas and start doing stuff 24:22.720 --> 24:39.920 or anything like that no yeah it's really it's a greedy yeah that is really interesting so 24:39.920 --> 24:48.960 the question is about um like styling across multiple different mapping libraries is that 24:48.960 --> 24:55.200 like a good summary yeah they're like how do you so the the the the the answer is um it's actually 24:55.200 --> 24:59.680 like it's quite fortunate really because a lot of the mapping libraries actually have quite 24:59.680 --> 25:04.880 similar levels of functionality so you can generally feel like the basic styling you can 25:05.520 --> 25:11.680 style consistently across like all the different mapping libraries quite like relatively easily 25:11.680 --> 25:16.720 it gets more complicated when you do like more obviously like more complex styling so if you have 25:16.800 --> 25:23.120 things like like one example is that I've we've wanted to do for ages is like dashed lines 25:23.120 --> 25:30.240 and so there's just one it's like for some reason like map map libre doesn't support dashed lines 25:30.240 --> 25:34.880 or it doesn't support dashed lines but it doesn't support like dashed lines that are 25:35.680 --> 25:44.080 based like powered by data if that makes sense so you can dynamically change the how the gaps 25:44.160 --> 25:48.640 between all the dashes and all this kind of stuff so um yeah you're kind of the problem is 25:48.640 --> 25:54.080 like one of the side effects of um supporting all the libraries is you're kind of tied to like 25:54.080 --> 25:58.720 the lowest common denominator if that makes sense because you have to you can't just add support 25:58.720 --> 26:03.680 for like things that the other libraries don't also support so yeah it's a bit of a problem but 26:03.680 --> 26:09.680 seems to work okay for the basic stuff yeah 26:14.320 --> 26:30.480 I missed the like first part of the question so with snapping like how much can you 26:30.480 --> 26:37.040 the questions like how much can you configure it so yeah good question so you can do 26:37.840 --> 26:43.120 coordinate snapping so that's a snapping to the vertices of like other let's say like polygons 26:43.200 --> 26:47.840 that you're you've drawn you can snap to the line kind of like as I was sharing but there's also 26:47.840 --> 26:53.600 we have a thing called like two custom and so two custom is essentially like a function and then 26:54.400 --> 27:01.600 like it just expects you to return some coordinate so in two custom you could snap to an external 27:01.600 --> 27:06.800 data set or you could snap to let's say or you could snap to like right angles there's an example 27:06.800 --> 27:14.000 like if you just wanted to only draw like right angled polygons and so there is a way to allow 27:14.000 --> 27:18.960 if you really want like really bespoke custom snapping behavior then they have this like two 27:18.960 --> 27:31.520 custom function that allows you to snap to like anything you want basically so two custom is like a 27:31.520 --> 27:37.120 is a feature within terror draw but then if you wanted then it's up to you to decide like 27:37.840 --> 27:45.680 the minutia of like how what you want to snap to basically yeah thanks