App Engine，PIL和覆盖文本 [英] App Engine, PIL and overlaying text

问题描述

我正在尝试在GAE上的图像上叠加一些文字。现在他们暴露了PIL库它不应该是问题。

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

这就是我所拥有的。它有效，但我不禁想到我应该直接写入背景图像，而不是创建一个单独的叠加图像然后合并。

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.

我可以使用 Image.frombuffer 或其他什么，我已经给了它一个但是我是只是没有得到它...

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)

推荐答案

您应该使用 [Image.open] [1] 方法。 Image.frombuffer 和 Image.fromstring 解码像素数据而不是原始图像。

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

在你的情况下，你可以使用类似的东西：

In your case you could use something like:

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

这篇关于App Engine，PIL和覆盖文本的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！