Django detect dominant color of an image

问题

I have a blog with a lot of articles, I was wondering how to build a function that can detect the dominant color of each article image and for each article set the background with the dominant color.

(I am using Django +1.8 and Python 3.4.x)

I'm trying to build it from scratch, what are the steps?

What should the color detection function looks like?

any thoughts/suggestions?

回答1:

Yeah I just wanted a schema of how it would work on django

Let's assume a skeleton similar to below

class Article(Model):
    background_color = CharField(max_length=6) # hex code of color

class AricleImage(Model):
    article = ForeignKey(Article)
    image = ImageField()

    def get_dominant_color(self):
         return _get_dominant_color(self.image.open())
         # or pass self.image.file, depending on your storage backend
         # We'll implement _get_dominant_color() below later

    def set_article_background_color(self):
         self.article.background_color = self.get_dominant_color()

Django provices a ImageField which inherits from FileField, which provides a .open() method, which is what we've used above to get a handle on the image file (which will be passed to our scipy/PIL code below)

...to build a function that can detect the dominant color of each article image and for each article set the background with the dominant color.

To run this on all articles we can do:

for article_image in ArticleImage.objects.all():
    article_image.set_article_background_color()

Let's adapt the code from this answer and make a function out of it:

import struct                                                               
import Image                                                                
import scipy                                                                
import scipy.misc                                                           
import scipy.cluster                                                        

NUM_CLUSTERS = 5                                                            

def _get_dominant_color(image_file):                                       
    """                                                                     
    Take a file object and return the colour in hex code       
    """                                                                     

    im = image_file                                            
    im = im.resize((150, 150))      # optional, to reduce time              
    ar = scipy.misc.fromimage(im)                                           
    shape = ar.shape                                                        
    ar = ar.reshape(scipy.product(shape[:2]), shape[2])                     

    print 'finding clusters'                                                
    codes, dist = scipy.cluster.vq.kmeans(ar, NUM_CLUSTERS)                 
    print 'cluster centres:\n', codes                                       

    vecs, dist = scipy.cluster.vq.vq(ar, codes)         # assign codes      
    counts, bins = scipy.histogram(vecs, len(codes))    # count occurrences 

    index_max = scipy.argmax(counts)                    # find most frequent
    peak = codes[index_max]                                                 
    colour = ''.join(chr(c) for c in peak).encode('hex')                    
    return colour

Set the article background in the template

And lastly but not least, when you render the article, just use {{article.background_color}}

e.g. if you want to override a generic style.css you could define a <style></style> block in the HTML

<style>
body {
    background: #{{article.background_color}};
}
</style>

(Just an example, you can also make django generate a /css/style-custom.css file to include after your main /css/style.css)

来源：https://stackoverflow.com/questions/34958777/django-detect-dominant-color-of-an-image

标签

python

django

detection