June 2018 Update

Task/Fractal-tree/BASIC/fractal-tree-2.basic

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+ 'Fractal Tree - for Run Basic - 29 Apr 2018
+ 'from BASIC256 - http://rosettacode.org/wiki/Fractal_tree#BASIC256
+ 'copy this text and go to http://www.runbasic.com
+
+WindowWidth  = 500  'Run Basic max size 800 x 600
+WindowHeight = 350
+c = 255  '255 for white '0 for black
+
+ graphic #w, WindowWidth, WindowHeight
+ #w cls("black")  'black background color
+ #w color(c,c,c)  'changes color to white
+
+level = 10             ' initial values
+leng = 50		
+x = 230: y = 325       ' initial values x = 230: y = 285
+pi = 3.1415			
+rotation = 3.1415/2
+
+'A1 = pi/27 : A2 = pi/8	    ' constants which determine shape
+'C1 = 0.7 : C2 = 0.85       ' tree is drifted left
+
+A1 = pi/9 : A2 = pi/9	' constants which determine shape
+C1 = 0.85 : C2 = 0.85   ' Symmetrical Tree
+
+dim xs(level+1) : dim ys(level+1)	' stacks
+
+print : print "Welcome to the Run BASIC Fractal Tree Program"
+#w color("green") 'color green
+gosub [tree]
+ render #w
+' imgsave "Fractal_tree_BASIC-256.png", "PNG"
+Print "Thank you and goodbye"
+end
+
+[tree]
+	xs(level) = x : ys(level) = y
+	gosub [putline]
+	if level>0 then
+		level = level - 1
+		leng = leng*C1
+		rotation = rotation - A1
+		gosub [tree]
+		leng = leng/C1*C2
+		rotation = rotation + A1 + A2
+		gosub [tree]
+		rotation = rotation - A2
+		leng = leng/C2
+		level = level + 1
+	end if
+	x = xs(level) : y = ys(level)
+	return
+
+[putline]
+	yn = -1*sin(rotation)*leng + y
+	xn = cos(rotation)*leng + x
+                #w line(x,y,xn,yn)
+	x = xn : y = yn
+	return
+'end of code
+End