App Engine, PIL and overlaying text

Question

I'm trying to overlay some text over an image on GAE. Now they expose the PIL library it should not be problem.

Here's what I have. It works, but I can't help think I should be writing directly to the background image rather than creating a separate overlay image and then merging.

Can I use Image.frombuffer or something, I've given it a go but I'm just not getting it...

from PIL import Image, ImageDraw, ImageFont
from google.appengine.api import images
from google.appengine.ext import blobstore
from google.appengine.api import files

def compose(key):

    # create new image
    text_img = Image.new('RGBA', (800,600), (0, 0, 0, 0))
    draw = ImageDraw.Draw(text_img)
    draw.text((0, 0), 'HELLO TEXT', font=ImageFont.load_default())

    # no write access on GAE
    output = StringIO.StringIO()
    text_img.save(output, format="png")
    text_layer = output.getvalue()
    output.close()

    # read background image
    blob_reader = blobstore.BlobReader(key)
    background = images.Image(blob_reader.read())

    # merge
    merged = images.composite([(background, 0, 0, 1.0, images.TOP_LEFT), 
                               (text_layer, 0, 0, 1.0, images.TOP_LEFT)], 
                               800, 600)

    # save
    file_name = files.blobstore.create(mime_type='image/png')
    with files.open(file_name, 'a') as f:
        f.write(merged)
    files.finalize(file_name)

Plz, how could you install PIL on googleappengine? Thank you — armandomiani, Apr 06 '15 at 17:04

score 2 · Accepted Answer · edited Oct 02 '12 at 23:21

2

You should use the [Image.open][1] method instead. Image.frombuffer and Image.fromstring decode pixel data not raw images.

In your case you could use something like:

blob_reader = blobstore.BlobReader(key)
text_img = Image.open(blob_reader)
.........

edited Oct 02 '12 at 23:21

bradley

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answered Oct 02 '12 at 18:08

Sebastian Kreft

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I get an error with that: `raise IOError("cannot identify image file")` – bradley Oct 02 '12 at 18:42
What type of image are you trying to load? Also could you try using the following `text_img = Images.open(StringIO(blob_reader.read))`. – Sebastian Kreft Oct 02 '12 at 19:06
They are just standard jpegs. I get `TypeError: 'module' object is not callable` with using StringIO. – bradley Oct 02 '12 at 19:33
You need to use `from StringIO import StringIO`. – Sebastian Kreft Oct 02 '12 at 19:52
That's strange. I tried it in my local environment with a jpeg and it works just fine. Can you download the image and see if you can load it using just plain python + PIL. It may be that PIL does not like the image. – Sebastian Kreft Oct 02 '12 at 20:43
Ok, it worked when using the open command in plain python. [Example](http://hastebin.com/geyosapeke.py). So it looks like it's some problem with the blob_reader...? – bradley Oct 02 '12 at 22:38
Can you modify your example to read `img = Image.open(StringIO(open('test.jpg').read())))`. Also, did you check that your local image is the same as the one uploaded. – Sebastian Kreft Oct 02 '12 at 22:45
That works. Swapping that to `img = Image.open(StringIO(blob_reader.read()))` in my GAE app definitely does not work though... Here is the image: [Image](http://s3.uploader.nodejitsu.com.s3.amazonaws.com/1349218516317/test.jpg) – bradley Oct 02 '12 at 22:59

score 2 · Answer 2 · answered Oct 02 '12 at 23:01

2

You need to open the image with PIL, not the app engine image type (another answer was off by one character: Image, not Images):

blob_reader = blobstore.BlobReader(key)
text_img = Image.open(blob_reader)

answered Oct 02 '12 at 23:01

mjibson

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score 0 · Answer 3 · answered Oct 02 '12 at 20:36

0

To draw directly on the background image would be the most straightforward:

draw = ImageDraw.Draw(background)
draw.text((0, 0), 'HELLO TEXT', font=ImageFont.load_default())

answered Oct 02 '12 at 20:36

Mark Ransom

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This gives me this error: `AttributeError: 'Image' object has no attribute 'load'` – bradley Oct 02 '12 at 22:43

App Engine, PIL and overlaying text

3 Answers3

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