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Sober come back again in this exercise we're going to use a combination of a wire rotation just to recognize

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that I you I pinched the riser to rotate on a scale a wide view.

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So I'm going to pause the video for a few seconds.

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You give it a shot on your own.

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And then if you wanted to can follow along with my solution as well.

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OK.

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So I'm going to go to Mexico now and I'm going to start a new project called Just shows and transform

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because that's essentially what it is a transformation.

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And my storyboard I'm going to make myself a you I view which I'm going to make it to be 256 on 256.

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As always this part of the work I'm actually going to go through them quite quickly because I know that

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you guys know exactly how to do it you don't really need my help with it.

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So this is the red box and that's all I need in my interface field.

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Now my actual programming is swift.

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I need to have two gestures so I'm going to say let's call it wrote just that's going to be a rotation

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just for recognizer.

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I'm going to have a vowel let's call it scaler just it's going to be a u i pinch gesture recognizer.

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Now in my view a lot.

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I'm going to go ahead and essentially initialize both of them.

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There is really practically no difference between doing both of these in the interface there or if you

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want to do it here in the court are would both work exactly identically with on one end within the code

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so that we get to see it here as well.

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So it just becomes you like rotation just for recognizer of yourself.

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And we need to have an action with a selector.

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So I'm going to say that action is called rote action or something to that effect.

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And then I'm going to have to say I have a scale gesture which is going to be a I pinched gesture recognizer

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with Target's self and action being a selector Salek the center of a scale action.

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So now I need to have both of these actions.

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So I'm going to say a function rotation action and it has an arc.

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It doesn't actually need to have an argument so there isn't.

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I thought first I can have the argument is because I wanted to get the gesture but the gestures already

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have a kind of a global variable.

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So I don't need to have an argument here.

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So I have a rotation action and I have the other one which is called the scalar action and that's that

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one.

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Finally in my view that note I'm going to have to say we should add both of these to our red box.

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So when I say red box dot I'll just show recognizer Roths gesture and the red box thought I just recognize

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the scale gesture.

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And finally this is giving me an error saying that your selector methods are not exposed as objective

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see.

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So I'm going to have to do two.

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This is something we have seen many times before.

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The part of swift for I'm guessing and the new versions this will be this will be gone.

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So that's about that.

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My view of the lot of both of the gestures are initialized underboss applied to the red box.

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And now we have to actually do teams with them in their functions.

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So I'm going to fold this one and I'm going to go to my rotation action and say in the rotation action

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red box dot transforms becomes red box start transformed those rotated.

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And the value of they want rotate is the rotation of the rotation gesture.

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I'm going to say let's new wrote to be rotations just sheer dot rotation and I'm going up right.

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Got C.G. fruit in here.

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Now I'm working on this application.

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Even though I know it is not going to work because I want to show you something that is a very important

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concept something that is going to go wrong now and we have to fix it once it loads.

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We should see some really unexpected results so if I try to do this you can see that it's rotating with

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really unexpected values.

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And the reason for it is this the value of the rotation just is constantly adding to itself.

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So if I'm rotating these and try to only look at the two tops that I have on the screen you find rotate

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this say 90 degrees which is like this.

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That's going to be 90 degrees that is being recorded into my rotation just share and then when I wrote

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it down under 90 degrees the first 90 degrees and the second one are getting our data to each other.

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So it's kind of adding the values one is there by the time itself and to remedy that well you're going

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to do it if you're going to reset this value to zero every time we make a rotation so I'm going to come

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in here and say well we got the value we rotated the red box.

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Now you have to reset to zero.

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So let's go ahead and check it out again.

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What I read on the application and this time in every roll cycle we're going to add a little rotation

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to the red box.

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But then it's going to zero itself out and if we rotate the way we wanted rotate so what station is

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working the way you want it to rotate.

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So that's one thing that you have to keep in mind that the amount of rotation is actually being constantly

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added tweets if we will face a very similar situation with this scale.

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So in this case I'm going to say let me show a scale that's going to be a scale just sheer scale and

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this value is actually constantly multiplying itself by the previous one because it's a ratio so the

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ratio is based on the default value of one.

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And now he's saying well it's now 1.1 times of the previous one.

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And then when it gets another one it's not going to multiply by the default one is going to multiply

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by the previous one which is not something we want.

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So I'm going to say Redbox not transform transform is going to be a red box not transform the scale

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the boy.

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And the value we want is the newest scale for both x and y.

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Newer scale but once I'm done with that I'm going to say a scale just sheer scale defaulted back to

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one.

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Don't keep the current value in it.

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So I'm going to run this again.

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And now we can scale properly and we can also rotate properly sometimes that the gesture doesn't really

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recognize which one you're trying to do with a rotation you're attempting or it is the escape tempting

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but that's perfectly fine.

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And yeah that's that's why I have to tell you about these two guys.

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There is another thing that you might want to keep an eye on.

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And that's the state of a gesture recognizer are the states are very similar to the same states that

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we have for touches.

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They are begin are unchanged.

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And so sometimes you can actually do things.

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It just shows doors and or does begin.

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And you can obviously read up on all of those on on the manual under header files as well.

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So that was it made this exercise and I would you in the next lesson.