[mapserver-users] [Python+MapScript] Convert imageObj to PIL Image
Hi All,
I've been testing today in Python, trying to get a MapScript imageObj into an
python Image object. This works via the following code:
map.transparent = MS_ON
map.selectOutputFormat('png8')
map.outputformat.imagemode = MS_IMAGEMODE_RGBA
map.outputformat.transparent = MS_ON
img = map.draw()
mem_png = StringIO.StringIO(img.saveToString())
_img = Image.open(mem_png)
However, the _img file lost its transparency, even though it's still (or again)
PNG. There MUST be a better way of getting the PNG file into PIL, right?
Something besides writing it to a tempfile, opening it, and deleting it?
On a side note, I only use this rendered image temporarily, I only need to cut
it up in smaller bits and return those to my client. So if there's some sort of
format that supports transparcency but without the PNG compression overhead,
that would be even better!
Regards,
Jelmer Baas
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Re: [mapserver-users] [Python+MapScript] Convert imageObj to PIL Image
IIRC, PIL does not support 8bit pngs with transparency, so writing it
to a file won't help. If you need alpha, you'll have to stick with
32bit pngs.
--
thomas
On Fri, Sep 7, 2012 at 3:35 PM, Jelmer Baas b...@speerit.nl wrote:
Hi All,
I've been testing today in Python, trying to get a MapScript imageObj into an
python Image object. This works via the following code:
map.transparent = MS_ON
map.selectOutputFormat('png8')
map.outputformat.imagemode = MS_IMAGEMODE_RGBA
map.outputformat.transparent = MS_ON
img = map.draw()
mem_png = StringIO.StringIO(img.saveToString())
_img = Image.open(mem_png)
However, the _img file lost its transparency, even though it's still (or
again) PNG. There MUST be a better way of getting the PNG file into PIL,
right? Something besides writing it to a tempfile, opening it, and deleting
it?
On a side note, I only use this rendered image temporarily, I only need to
cut it up in smaller bits and return those to my client. So if there's some
sort of format that supports transparcency but without the PNG compression
overhead, that would be even better!
Regards,
Jelmer Baas
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Re: [mapserver-users] [Python+MapScript] Convert imageObj to PIL Image
Oh, wow, that was so simple. I changed
map.selectOutputFormat('png8')
to
map.selectOutputFormat('png24')
And done. Strangely, though, saving it to a file and re-opening *does* work!
Thanks for the quick reply!
--
Jelmer
-Original Message-
From: thomas bonfort [mailto:thomas.bonf...@gmail.com]
Sent: Friday, September 07, 2012 15:50
To: Jelmer Baas
Cc: mapserver-users@lists.osgeo.org
Subject: Re: [mapserver-users] [Python+MapScript] Convert imageObj to PIL Image
IIRC, PIL does not support 8bit pngs with transparency, so writing it
to a file won't help. If you need alpha, you'll have to stick with
32bit pngs.
--
thomas
On Fri, Sep 7, 2012 at 3:35 PM, Jelmer Baas b...@speerit.nl wrote:
Hi All,
I've been testing today in Python, trying to get a MapScript imageObj into an
python Image object. This works via the following code:
map.transparent = MS_ON
map.selectOutputFormat('png8')
map.outputformat.imagemode = MS_IMAGEMODE_RGBA
map.outputformat.transparent = MS_ON
img = map.draw()
mem_png = StringIO.StringIO(img.saveToString())
_img = Image.open(mem_png)
However, the _img file lost its transparency, even though it's still (or
again) PNG. There MUST be a better way of getting the PNG file into PIL,
right? Something besides writing it to a tempfile, opening it, and deleting
it?
On a side note, I only use this rendered image temporarily, I only need to
cut it up in smaller bits and return those to my client. So if there's some
sort of format that supports transparcency but without the PNG compression
overhead, that would be even better!
Regards,
Jelmer Baas
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