#
#CS 1301 - Jay Summet - Donated to the public domain Nov 2008.
#
#Example of a special effect that fades an image to black and then stores
#an animated gif of it.
#
#

from myro import *

#fadePicture
#
# This function takes a picture, and darkens it.

def fadePicture(picture, amount):

    for pixel in getPixels(picture):
        r = getRed(pixel)
        g = getGreen(pixel)
        b = getBlue(pixel)

        r = r - amount
        g = g - amount
        b = b - amount
        
        #The set functions will limit negative values to zero for us!
        setRed(pixel,r)
        setGreen(pixel,g)
        setBlue(pixel,b)

        
# Test for fadePicture
##p = loadPicture("class1.jpg")
##show(p)
##
##fadePicture(p, 100)
##show(p, "faded")



#Fade-To-Black:
# It gradually fades a picture, darker and darker, until
# all the pixels are black. It returns a list of pictures
# where the first picture is the original image, and each
# subsequent picture is a darker version of the one that
# came before it.

def fadeToBlack(picture,frames,amount):
    outputList = []

    outputList.append(picture)

    #Do our work on a copy of the original.
    cp = copyPicture(picture)

    for i in range(frames):
        #User Output so they know we are still working
        print "fade number: ", i
        
        #fade the picture
        fadePicture(cp, amount)
        outputList.append(cp)
        cp = copyPicture(cp)


    #return the list:
    return(outputList)


p = loadPicture("class1.jpg")

myList = fadeToBlack(p,5, 25)
print "len of myList:", len(myList)

print "Showing pictures!"
for i in myList:
    show(i)
    wait(1)

print "saving to an animated gif!"
savePicture(myList, "fade_to_black.gif")