Adventures with Pillow Part 1

I am in the middle of building an app and need to put together several promo videos for Twitter and Instagram, and man it is boring. So I thought 'how can I automate this process?', so welcome to this post.

What I am going for is a selection of images, greyscaled flipping through with our logo on the front. So my approach was to use python, pillow and ffmpeg to build something. This could be disastrous.

Images

To start a few pre-flight checks, a variable for the test image and to check for/create a processed folder for the final images to go.

import os, errno

from PIL import Image, ImageFont, ImageDraw
testImage = 'test.png'
cwd = os.getcwd()

image_dir = os.path.join(cwd, 'images')

default_dir = os.path.join(cwd, 'processed')try:
    os.makedirs(default_dir)except OSError as e:
    if e.errno != errno.EEXIST:
        raise

I am going to build a function that will do all of the processing, but first going to run on one image before looping through all of the one I need. The first process is to resize image. This is just going to social media promo video so I don't want massive images. I do this simply with the thumbnail method. Using im.show() will display the image on your OS, on mac will open in preview.

def processImage(imageFile):
    # Resize image    maxsize = (1000, 1000)
    im = Image.open(imageFile)
    im.thumbnail(maxsize)
    im.show()

Next I want to crop out the centre to give me a nice square image. The final square image is gonna be 600px x 600px. The crop function will take the top left corner and crop a box of dimension. I have the latter but to get the start location I will have to get the size of the height of the image, divid by 2 and minus 300px, then the same for the width.

def processImage(imageFile):
    # Resize image    ...

    # Crop center of an image out    halfCropArea = 300
    halfWidth = im.size[0] / 2    halfHeight = im.size[1] / 2    startWidth = halfWidth - halfCropArea
    startHeight = halfHeight - halfCropArea
    cropWidth = halfWidth + halfCropArea
    cropHeight = halfHeight + halfCropArea

    cropped = im.crop((startWidth, startHeight, cropWidth, cropHeight))

    cropped.show()

Next I need to convert to greyscale. will simply use a convert but will look in to filters another time.

def processImage(imageFile):
    ...

    # Apply greyscale    greyscale = cropped.convert('LA')
    img = greyscale.convert('RGB')

Finally to add the logo which is set to 144px square. To set in the middle I set (600 -144)/2 = 228 to top left and then 228 + 144 for bottom right.

def processImage(imageFile):
    ...

    # Add icon    iconImage = Image.open('icon.png')
    iconImage.thumbnail((144,144))
    img.paste(iconImage, (228, 228, 228 + 144 , 228 + 144))

    img.show()

Now I am gonna save to the new folder and also added an argument to the function for a new filename.

Movie Time

To get all of the images processed, I am gonna look at the folder with all of the images in and then loop through them. These going to be the frames of my video.

def processFolder():
    images = os.listdir(image_dir)
    for count, image in enumerate(images):
        filename = '%04d.png' % count
        imageFile = os.path.join(image_dir, image)
        print filename, imageFile
        processImage(imageFile, filename)

processFolder()

Inside the directory with my script I have put the ffmpeg library and just run the command form the script.

os.system('./ffmpeg -f image2 -r 2 -i ./processed/%04d.jpg -y -an -vf fps=30 -crf 25 -vcodec libx264 ./processed/video.mp4')

And Voila!!!

We Love #London #Photography so show us what you got!!! #Hashtag10 pic.twitter.com/YT3zkseffi

— Travista (@TravistaApp) August 23, 2017