Python: Image animation using PIL

One way to achieve an image animation is to generate a series of images and then combine them into an image format that supports animation.

One such format is an animated gif Image file.

The Python PIL library supports this. This page looks at using 3D images created using matplotlib and creating an animated GIF (Graphics Interchange Format) image.

Here is an animation of a pentagram, which has embedded Golden Ratio's and was studied by Pythagoras.

Animated pentagram

Here is an image of the 36 images generated with a bounding box around each one. A clipping path is used to capture just the part needed for an image.

Here is a static image.

Static pentagram

Note that there are two cycles in the flipping and that the progression is geometric and not linear. This is needed so that the animation appears smooth and continuous.

In Python, the PIL (Python Imaging Library) can be used to create animations.

The images used are from the code creating images in Matplotlib: 3D plots .

Here is the Python code.

from PIL import Image

# Windows accepts both backslash and forward slash
# Linux accepts only forward slash

# original images were at 15 degree rotations
basePs1 = "./"
baseName1 = "plot41-2"
baseStart1 = 1
baseStop1 = 6

animateFs1 = "./{0:s}.gif".format(baseName1)

basePrefix1 = "{0:s}{1:s}-0".format(basePs1,baseName1)
baseSuffix1 = ".png"

# how many times to loop, 0 is never stop
loop1 = 0
# duration of each frame
duration1 = 200

imageFsList1 = [basePrefix1 + str(digit1) + baseSuffix1 for digit1 in range(baseStart1,baseStop1+1)]

print("Image file list: (input, static)")
for imagePos1,imageFs1 in enumerate(imageFsList1):
	print("\t{0:d}. \"{1:s}\"".format(imagePos1+1,imageFs1))
print("")
print("Image file list: (output, animated)")
# separate list into head and tail parts
imageHead1,*imageTailList1 = [Image.open(fs1) for fs1 in imageFsList1]

imageHead1.save(fp=animateFs1,format="GIF",append_images=imageTailList1,save_all=True,duration=duration1,loop=loop1)

Here is the output of the Python code.

Image file list: (input, static)
	1. "./plot41-2-01.png"
	2. "./plot41-2-02.png"
	3. "./plot41-2-03.png"
	4. "./plot41-2-04.png"
	5. "./plot41-2-05.png"
	6. "./plot41-2-06.png"

Image file list: (output, animated)

Here is the animated image.

Note the following.

An animated GIF image does not provide a lot of control over certain animation features.
Some low-level control is possible if the API (Application Program Interface) (in this case, matplotlib) supports that fine-grained control.

One simple way to vary the length of one frame is to just repeat that frame more than once. The GIF specification permits fine-grained control but not necessarily the API to create the animated image.