Jython (JES) - Function for rotating a picture [duplicate] - image

Question

I need to write a function spin(pic,x) where it will take a picture and rotate it 90 degrees counter clockwise X amount of times. I have just the 90 degree clockwise rotation in a function:
def rotate(pic):
width = getWidth(pic)
height = getHeight(pic)
new = makeEmptyPicture(height,width)
tarX = 0
for x in range(0,width):
tarY = 0
for y in range(0,height):
p = getPixel(pic,x,y)
color = getColor(p)
setColor(getPixel(new,tarY,width-tarX-1),color)
tarY = tarY + 1
tarX = tarX +1
show(new)
return new
.. but I have no idea how I would go about writing a function on rotating it X amount of times. Anyone know how I can do this?

Answer 1

You could call rotate() X amount of times:
def spin(pic, x):
new_pic = duplicatePicture(pic)
for i in range(x):
new_pic = rotate(new_pic)
return new_pic
a_file = pickAFile()
a_pic = makePicture(a_file)
show(spin(a_pic, 3))
But this is clearly not the most optimized way because you'll compute X images instead of the one you are interested in. I suggest you try a basic switch...case approach first (even if this statement doesn't exists in Python ;):
xx = (x % 4) # Just in case you want (x=7) to rotate 3 times...
if (xx == 1):
new = makeEmptyPicture(height,width)
tarX = 0
for x in range(0,width):
tarY = 0
for y in range(0,height):
p = getPixel(pic,x,y)
color = getColor(p)
setColor(getPixel(new,tarY,width-tarX-1),color)
tarY = tarY + 1
tarX = tarX +1
return new
elif (xx == 2):
new = makeEmptyPicture(height,width)
# Do it yourself...
return new
elif (xx == 3):
new = makeEmptyPicture(height,width)
# Do it yourself...
return new
else:
return pic
Then, may be you'll be able to see a way to merge those cases into a single (but more complicated) double for loop... Have fun...