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Thread: Placing colored pixels next to each other




Placing colored pixels next to each other
user name
2006-10-30 18:16:10
> Steve Lianoglou wrote:
>
>> I'm using OS X so the show() function is defaulting
to use  
>> Preview.app.
>
> and JPEG, I'm afraid:
...
> (I wonder how I missed that).
>
> what formats do Preview.app support?  can you try
setting format to  
> None
> (that writes a PPM file using an optimized code path),
or perhaps  
> "PNG".

Bingo!

Preview.app supports pretty much any format you can throw at
it ...  
except for perhaps PPM(?)

I went into the Image.py file and set the format=None.
Preview wasn't  
showing anything here ... it was being called alright, but
no image  
was popping up.

I went back in there and changed the format to
"PNG" and went through  
my song and dance and it looks to be working just perfectly.
No  
artifacts around adjacent pixels.

Thanks for pointing me in the right direction with that. If
there's  
anything else you'd like me to test w.r.t functionality on
the mac,  
I'd be happy to.

Lastly, if I want to use transparency, would creating an
RGBA image  
be the way to go?

I'm setting the color with a 4-tuple, of which I think the
last  
number is the transparency (0-255?), but it seemingly has no
effect  
on the opacity of the area I'm coloring (or the pixel).

I'm trying to create a "heat map" over my matrix,
where full opacity  
would be something like "the strongest signal",
and then I'd decrease  
opacity/increase transparency in the blocks/pixels where the
signal  
is weaker.

Perhaps merging two images is how I should be doing it? I
found this  
post that seems to take this approach:
http://mail.python.org/pipermail/python-list/19
99-May/003369.html

Is that the best way to do it?

Thanks again,
-steve
_______________________________________________
Image-SIG maillist  -  Image-SIGpython.org
htt
p://mail.python.org/mailman/listinfo/image-sig
Placing colored pixels next to each other
user name
2006-10-30 18:16:10
> Steve Lianoglou wrote:
>
>> I'm using OS X so the show() function is defaulting
to use  
>> Preview.app.
>
> and JPEG, I'm afraid:
...
> (I wonder how I missed that).
>
> what formats do Preview.app support?  can you try
setting format to  
> None
> (that writes a PPM file using an optimized code path),
or perhaps  
> "PNG".

Bingo!

Preview.app supports pretty much any format you can throw at
it ...  
except for perhaps PPM(?)

I went into the Image.py file and set the format=None.
Preview wasn't  
showing anything here ... it was being called alright, but
no image  
was popping up.

I went back in there and changed the format to
"PNG" and went through  
my song and dance and it looks to be working just perfectly.
No  
artifacts around adjacent pixels.

Thanks for pointing me in the right direction with that. If
there's  
anything else you'd like me to test w.r.t functionality on
the mac,  
I'd be happy to.

Lastly, if I want to use transparency, would creating an
RGBA image  
be the way to go?

I'm setting the color with a 4-tuple, of which I think the
last  
number is the transparency (0-255?), but it seemingly has no
effect  
on the opacity of the area I'm coloring (or the pixel).

I'm trying to create a "heat map" over my matrix,
where full opacity  
would be something like "the strongest signal",
and then I'd decrease  
opacity/increase transparency in the blocks/pixels where the
signal  
is weaker.

Perhaps merging two images is how I should be doing it? I
found this  
post that seems to take this approach:
http://mail.python.org/pipermail/python-list/19
99-May/003369.html

Is that the best way to do it?

Thanks again,
-steve
_______________________________________________
Image-SIG maillist  -  Image-SIGpython.org
htt
p://mail.python.org/mailman/listinfo/image-sig
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