# Image beautifier in Python


To make a better reading experience for your audience, using images is one of the best ways.
I intend to use this blog to write about my ideas. To document courses I have gone through. To report the technical problems I have faced.
To clarify my points, sometimes, it is necessary to add images to my writing.

I want all the images displayed on the blog to be consistent.
I want to add a background to all my images. 
And the process to do this needs to be as simple as possible.
I don't want to go to my image processor every time I need to add an image.

So let's take a screenshot of a terminal and add a background to it.
We are going to use Python and  Pillow for this, so let's first import the library.


```python
from PIL import Image
```

Let's open up the image I have using the library.


```python
im = Image.open("terminal.png")
display(im)
```

![png](https://cdn.hashnode.com/res/hashnode/image/upload/v1636188953366/_drgfzHrYm.png)

Now let's add a background to this image. To do that, we need to create a new image and paste our screenshot image. I will make an image where the size is 50% larger than the original width and height. And calculate an offset, so our screenshot is placed right in the middle.


```python
def generate_ss(im):
    # Get the current image size
    img_width, img_height = im.size

    # Make new size with 50% more for the width and height
    bg_size = (img_width + (img_width // 2),
               img_height + (img_height // 2))

    # Calculate offset
    offset = ((bg_size[0] - img_width) // 2,
              (bg_size[1] - img_height) // 2)

    im_with_bg = Image.new("RGB", bg_size, "#c7ecee")
    im_with_bg.paste(im, offset, mask=im)

    return im_with_bg
```


```python
new_img = generate_ss(im)
display(new_img)
```

![png](https://cdn.hashnode.com/res/hashnode/image/upload/v1636188953401/9ckx231V-5.png)


A note about `im_with_bg.paste(im, offset, mask=im)` line. When you take a screenshot on your Mac to capture a window (using Command+Shift+4 and Space bar), you got an image that has a drop shadow and transparency on the surrounding box. If we don't use the `mask` keyword, the image will show up with a black box surrounding the image. You can see the black box because the image has transparency. And what we want is to create a composite image that blends the background and our image. That is why we need to use the `mask` keyword. Let me show you what it will look like if we don't use the `mask` keyword.


```python
bg_size = (im.size[0] + (im.size[0] // 2),
           im.size[1] + (im.size[1] // 2))
offset = ((bg_size[0] - im.size[0]) // 2,
          (bg_size[1] - im.size[1]) // 2)
im_with_bg = Image.new("RGB", bg_size, "#c7ecee")
im_with_bg.paste(im, offset)
display(im_with_bg)
```
    
![png](https://cdn.hashnode.com/res/hashnode/image/upload/v1636188953337/BQVSQ-ubp.png)


This is not what we want. 

## Adding a drop shadow

So the previous image comes with a drop shadow. Which makes it looks nice. Naturally, you ask, what if we want to add a drop shadow for pictures that do not come with one.

It turns out someone already made a function for this. You can find the drop shadow function [here](https://code.activestate.com/recipes/474116-drop-shadows-with-pil/).
The original recipe does not allow for the shadow color to have transparency. Here I tweak the function a bit to add that ability.

```python
from PIL import ImageFilter


def drop_shadow(image, offset=(5,5), background=0xffffff, shadow=0x444444, 
                border=8, iterations=3):
    """
    Add a gaussian blur drop shadow to an image.  
    image       - The image to overlay on top of the shadow.
    offset      - Offset of the shadow from the image as an (x,y) tuple. 
                  Can be positive or negative.
    background  - Background colour behind the image.
    shadow      - Shadow colour (darkness).
    border      - Width of the border around the image.  This must be wide
                enough to account for the blurring of the shadow.
    iterations  - Number of times to apply the filter.  More iterations 
                produce a more blurred shadow, but increase processing time.
    """
    # Create the backdrop image -- a box in the background colour with a 
    # shadow on it.
    totalWidth = image.size[0] + abs(offset[0]) + 2*border
    totalHeight = image.size[1] + abs(offset[1]) + 2*border
    back = Image.new("RGBA", (totalWidth, totalHeight), background)
    # Place the shadow, taking into account the offset from the image
    shadowLeft = border + max(offset[0], 0)
    shadowTop = border + max(offset[1], 0)
    back.paste(shadow, [shadowLeft, shadowTop, shadowLeft + image.size[0], 
               shadowTop + image.size[1]] )
    # Apply the filter to blur the edges of the shadow.  Since a small kernel
    # is used, the filter must be applied repeatedly to get a decent blur.
    n = 0
    while n < iterations:
        back = back.filter(ImageFilter.BLUR)
        n += 1
    # Paste the input image onto the shadow backdrop  
    imageLeft = border - min(offset[0], 0)
    imageTop = border - min(offset[1], 0)
    back.paste(image, (imageLeft, imageTop))
    return back
```


Now let's modify our generate_ss function. 


```python
def generate_ss(im, bg_color, **kwargs):
    # Get the current image size
    img_width, img_height = im.size
    
    # Make new image with 50% more for the width and height
    bg_size = (img_width + (img_width // 2),
               img_height + (img_height // 2))
    
    # Apply drop shadow
    shadow_settings = kwargs.get("shadow", {})
    img_shadow = drop_shadow(im, background=bg_color,
                             **shadow_settings)
    
    # Calculate offset
    new_img_width, new_img_height = img_shadow.size
    offset = ((bg_size[0] - new_img_width) // 2,
              (bg_size[1] - new_img_height) // 2)
    
    im_with_bg = Image.new("RGB", bg_size, bg_color)
    im_with_bg.paste(img_shadow, offset, mask=img_shadow)
    
    return im_with_bg
```

Okay, the function is ready. It is time to find a suitable parameter for the drop shadow. After trying multiple times, I found the setup that works.


```python
shadow_setup = {
    "offset": (2, 8),
    "border": 68,
    "shadow": (0, 0, 0, 50),
    "iterations": 60
}

book_cover = Image.open("book.jpeg")
new_im = generate_ss(book_cover, "#c7ecee", shadow=shadow_setup)
display(new_im)
```


    
![png](https://cdn.hashnode.com/res/hashnode/image/upload/v1636188953436/W4zDF4sJ-i.png)
    


## Summary

This article shows how easy it is to add background and drop shadow to images or screenshots you take using Python. In practice, I turn the code above into a command-line script. So every time I need to add pictures to my posts, I  run this command, and I got a beautiful screenshot.