CODEWITHSUNDEEP
pythonimagegoogle-app-enginepython-imaging-library
bradley
bradley

Reputation: 776

App Engine, PIL and overlaying text

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)

Upvotes: 3

Views: 2015

Answers (3)

Sebastian Kreft
Sebastian Kreft

Reputation: 8199

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)
.........

Upvotes: 2

maddyblue
maddyblue

Reputation: 16882

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)

Upvotes: 2

Mark Ransom
Mark Ransom

Reputation: 308392

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())

Upvotes: 0

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