Java Fractal Explorer [5/8]

in this video we're actually going to display the fractal on the screen but before we can do that we need a few more variables and a few more methods so let's get going so we are going to need some way to track where we are in the fractal and at what depth we are in the fractal so let's create create a default Zoom which is going to be 100% and we're also going to want to have a default top left Exposition and we're going to set that to be3 and we're also going to want a default top left y position along with that we're also going to want zoom factor which is going to be the default zoom and you can almost guess what's coming up next to top left X is going to be default top left X and top left Y is going to be default top left y so now that we have those variables created let's add one more method right here after add canvas let's make a method called update fractal this is probably going to be one of the most important methods um in our program because it's actually going to update the display so public void update fractal so what update fractal is going to do is it's going to go through every single Pixel on our canvas and change its color so to do that it's going to need to Loop through the canvas so let's start looping through all the pixels so while X is less than width x++ for y While y is less than the height y ++ so with X and Y we can get uh a single color on on our canvas but for every pixel we're going to want to transform the current X and Y positions on our canvas to X and Y positions in their complex plane because remember we want to grab that complex Point C and that complex Point C is going to be parameter and argument for compute iterations right here so I'm going to say C of R is going to be equal to get X position for x and C of I is going to be get y position for y um the reason C of R is associated with X is because the real values are on the X AIS and the imaginary values are on the Y AIS so let's make these two methods right now so private double get expose what this is going to do is going to transform the x coordinate into uh a point on our or rather a value on our complex plane so that's going to depend on two things it's going to depend on the resume factor and where top left X currently is I'm just going to give it to you it's Zoom Factor plus top left X and nearly the same thing for the Y just make sure you change all these X's to y's except one small detail if you recall the y axis is flipped so we need to put a negative sign instead of a positive sign and this is going these two methods together are going to to get our C of R and our C ofi and now we want to use those to call compute iterations which is going to return the the number of iterations so uh iteration count compute iterations C of r c ofi and the next thing we need to do is we actually need to create a color based on the number of iterations um so I'm going to create a very rudimentary make color method right now but we'll go more in depth in the next video so let's call this the the pixel color make color it's going to take the number of iterations we did and the last thing we need to do is say fractal image. set RGB at XY so at the pixel we're currently on to be that new pixel color oh and actually I lied one last thing is to call the method canvas. repaint and this should work once we finish implementing the make color method um which I'm going to make right here really quickly so int make color and if you remember this took the number of iterations so iter count and right now we're going to say that if the iteration count is the maximum number of iterations then we want to return black so that's going to be color. black. getet RGB uh otherwise we're just going to make the background blue so blue like this so let me recap what we just did we created a method called update fractal it Loops through all the pixels in in or on our canvas then we we transform those X and Y coordinates into points on our complex plane depending on what our top left X and top left Y and zoom Factor are next we calculate the number of iterations that that complex Point does and then based on the number of iterations that happen we get a different pixel color and then we set the pixel color on our fractal image and once that's all done we repaint on the canvas so let's see if if I have any bugs you never know unclean if we run this we just get a blue canvas so something went wrong I found our error y should be positive so let's go and run this and bingo as you can see we have a very rudiment Mand mandal broth set we can't click in and zoom we can't pan around but it's being displayed Right Here and Now guys thank you for watching and I'll see you in the next video