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This is just a short section to introduce
a type of puzzle, which is built on
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the sort of image manipulation code we've been doing. So the idea is, there's a picture of some
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mystery object. And the red, green and blue values in the image have just been
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messed up in some way. And so, what
you need to do is write code to fix the
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red, green, and blue values, and so reveal
the original image, and, and see what it is.
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So, here is an example I'm gonna do
here. This is the so called "Gold Puzzle".
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And, the idea, so there's, there's, some
object is shown here. And what's happened with this
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is that, first of all, the green
and blue values in the image have been just
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set with random values between zero
and 255. And actually, if you look at it,
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so it gives a kind of a, a snowy
appearance. And it, you can kinda see, there's,
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so there's some pixels where the
green is very high, some pixels where the blue is very high,
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they just look blue or green; and then there's these sort of turquoise pixels scattered through;
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so those are cases where, both the blue and the green are high. So that's one,
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one level of mess-up in this image. The other thing that's happened
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is that the image that we wanna recover, it's in the
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red values. In fact, it's exclusively in the red values. The green and blue are just, sort of, garbage.
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But the values have been divided by ten, so they're very dark. So, kind of what we're seeing here
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in the obscure version, is, there's, there's a dark red image
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behind there. And it's been covered with this, sort of bright random
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green blue snow, so we can't see it. So what we want to do is, write code to fix it.
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So let me start off here. So as usual, for these, I'm going to start off
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with just a blank text area to just write the code. And then down here there's a solution,
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"Show solution" button. So if you wanted to visit this page and try it yourself, you can, you can get the code that way.
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Alright, so the first thing I want to do, so here's, here's what it looks like if I just run it right here:
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the loop is empty; so if I run it, we just, we just get the, the puzzle image raw.
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Alright, so the first thing I'm going to do is I'll say
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pixel.setGreen(0)
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I'm going to punch out the green
values. I'm just going to get rid of them
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and we'll see what we get. Hmm, alright,
So now, well, it's better. Now, we just
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have this blue snow. We've at least gotten
rid of the green snow. So I'll get rid of the blue snow as well.
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So I'll say, pixel.SetBlue(0), we'll try that.
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Alright, hmm, So, I, I've got rid of the
snow. But now the problem is that the
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image, which is in the red values. It's
just so dark, we can't see it. So it is,
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it's technically there, but it's invisible. So what I need to is scale it back up,
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right? It's down there, I just need to make it brighter. So I'll say pixel.setRed of
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pixel-dot-getRed" Looks a little bit like the five, ten, twenty
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puzzles here. So I'm gonna, in this case, the instructions say that it was scaled down
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by a factor of ten. So I'll scale the red back up by a factor of ten.
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Huh, there we go. So that, that is the solution image. So,
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this is a picture of the Golden Gate Bridge, as seen from
the San Francisco side. Now,
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it's a little, obviously, it doesn't look quite
right. What's happened, is that, because
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the data is exclusively in the red, even
when we recover it, it just looks red. I mean, what's,
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what's happened, actually. Is this
is an essentially a black and white image
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and normally those are shown on a, on a
sort of black to white spectrum. In this case,
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the image is being shown on a black
to red spectrum. So it is the right image but it just,
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it has this red cast. For this sections we're gonna say that's good enough: you know,
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you can see what it's supposed to be. In a later section I'll show how to,
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how to fix that. And get it to look like a, a proper black and white image.
