Kivy with Python tutorial Part 8 - Simple Drawing Application

Key Takeaways

hello everybody and welcome to the eth Ki Basics tutorial video with python in this video we're going to make a sort of uh drawing application so to do that from where we are it's actually not very much code because we are already tracking on touchdown on touch and on touch move we actually aren't going to need on touch up but I'm just going to leave it here because it's cool that we even have that so uh with that let's go ahead and import one one more thing and that is going to be from k. Graphics we want to import line with a capital l and that's to actually draw a line basically now what we want to do is on touchdown we want to begin a line so think of like you know you have a pencil you put the pencil to the paper and then starts to make a mark and then as you drag it around it continues you know marking on the paper so that's what we kind of want to do want touchdown we want to begin that Mark and then we want to continue that Mark as long as our touch is moving on even though in theory you might think in your head well don't we have to do something ontouch up to stop the line drawing no because ontouch move will just cease to exist anymore so we actually don't need to do anything there but anyway uh we need line and that's really all we have to add as far as Imports are concerned and now we just need to code the on touchdown and move stuff so I'm going to call this uh I don't know draw class draw input and then before we forget we need to take this right here and instead of touch input down here it needs to be draw input so I just want to change that other than other than that we're ready to go so now we say with self. canvas and this is the canvas of our application uh so self. canvas is just referring to that so you don't really need to like define canvas or anything so with self. canvas what do we actually want to do well we're going to say touch. UD and UD now uh we're going to reference the line element in there and we're going to say that is equal to line and we're going to say the points of that line is right now going to only be a single point in the line but the points for now are equal to touch dox touch doy so literally the X and Y values of of uh where we touch down so line at the moment is literally uh just actually a point it's not really a line it's simply a point but then what we do is we've since we've got that now what we're going to do is that should I'm going just make sure we close that off right yes so now we've got a line there and that will actually show something but not very much and then now on touch move what we want to do is we're going to say touch. UD uh and then again again we're referencing the line element whoops line like this and then we're going to say dot points plus equals and we want to plus equals the exact same thing pretty much right here so plus equals this so again this is just the this is the line function and we're saying we already established touch. UD line equals line which we imported up here and where we say the points of line so where we basically said line do points cuz touch UD uh line is equal to basically this line right up here so now we're saying line. points which originally line dot points was touch just X and Y of the original touch now we're saying we want to add to those points and we're adding every single movement of touch X and touch y we just add all of those movements and that's really it that's all we have to do with this and so now we can just save and run this hopefully and here we have our application and yeah sure enough you can click and you can start to write things so hi awesome and then we can actually you know resize this and we'll see that okay we just gained a lot more space and uh now we can write even more stuff and I'm really good at writing with the mouse tutorials you probably wouldn't even know that was tutorials immediately anyway so that's that that's pretty much all of um the basic basics for using canvas anyways but that's pretty cool like how quickly you can uh actually you know reference the drawing ability and the canvas ability of uh K so anyways I hopefully you guys enjoyed if you have any questions or comments please please feel free to leave them below otherwise as always thanks for watching thanks for all the support and subscriptions and until next time