Flask Mailinglist

Re: PIL to create thumbnails automatically using tag

From:

Alex

Date:

2011-01-26 @ 17:10

OK, thanks.

Now I see the point. I will also need to add caching (saving of thumb to a
disk and getting it from the disk next time).

Probably I'll do MD5 over image url - save it on disk and next time do MD5
over the image name url again and check if this hashed image name is already
on the disk.

-Alex

On Wed, Jan 26, 2011 at 7:37 AM, Julien <jc63@free.fr> wrote:

> You can create something like this 
> 
> import Image, os, sys 
> 
> @app.route("/thumbs") 
> def thumbs(): 
> 
>     # not good (type of values) but something like this 
>     file = request.args.get('file', None) 
>     width = request.args.get('width', 120) 
>     height = request.args.get('height', 90) 
>     quality = request.args.get('height', 70) 
>     crop = request.args.get('crop', False) 
> 
>     # image 
>     img = Image.open(file) 
>     newpath = "" 
>     out = file(newpath, "w") 
>     resize(img, (width, height), crop, out, quality) 
> 
>     return send_file(out) 
> 
> 
> 
> def resize(img, box, fit, out, quality=75): 
>     '''Downsample the image. 
> 
>     script example : 
>  >>> import Image, os, sys 
>  >>> for filename in sys.argv[1:]: 
>  >>>     img = Image.open(filename).resize( (200,200) ) 
>  >>>     out = file(os.path.splitext(filename)[0]+"_thumb.jpg", "w") 
>  >>>     try: 
>  >>>         img.save(out, "JPEG") 
>  >>>     finally: 
>  >>>         out.close() 
> 
>     @param img: Image -  an Image-object 
>     @param box: tuple(x, y) - the bounding box of the result image 
>     @param fix: boolean - crop the image to fill the box 
>     @param out: file-like-object - save the image into the output stream 
>     ''' 
>     #preresize image with factor 2, 4, 8 and fast algorithm 
>     factor = 1 
>     while img.size[0] / factor > 2 * box[0] and img.size[1] * 2 / 
> factor > 2 * box[1]: 
>         factor *= 2 
>     if factor > 1: 
>         img.thumbnail((img.size[0] / factor, img.size[1] / factor), 
> Image.NEAREST) 
> 
>     #calculate the cropping box and get the cropped part 
>     if fit: 
>         x1 = y1 = 0 
>         x2, y2 = img.size 
>         wRatio = 1.0 * x2 / box[0] 
>         hRatio = 1.0 * y2 / box[1] 
>         if hRatio > wRatio: 
>             y1 = y2 / 2-box[1] * wRatio / 2 
>             y2 = y2 / 2 + box[1] * wRatio / 2 
>         else: 
>             x1 = x2 / 2-box[0] * hRatio / 2 
>             x2 = x2 / 2 + box[0] * hRatio / 2 
>         img = img.crop((x1, y1, x2, y2)) 
> 
>     #Resize the image with best quality algorithm ANTI-ALIAS 
>     img.thumbnail(box, Image.ANTIALIAS) 
> 
>     #save it into a file-like object 
>     img.save(out, "JPEG", quality=75) 
> #resize 
> 
> and call it from your template: 
> 
> <a href="{{ imagepath }}"> 
> <img src="{{ url_for('thumbs', file=imagepath, width=120, height=90) }}" 
> alt="" /> 
> </a> 
> 
> You have to adapt this, it's just a big approximation. 
> 
> Julien C. 
> 
> On 26/01/2011 10:59, Alex wrote: 
> > Hello, 
> > 
> > I'm a bit new to Flask and Python, what could be the best way to 
> > automatically create create links to resized images that are saved in 
> > flask app based on image url provided? 
> > 
> > For example {{ some_func('http://somesite.com/image.jpg', '140', '90', 
> > '70%') 
> > 
> > Thanks, 
> > Alex 
> 
>