[Tkinter-discuss] how to get all pixels enclosed by a canvas object

[Peng]

Thanks for your reply, Lion.

What I want to do is to select a region of interest (ROI) in a given
image.  I can display the image in a canvas widget and use
canvas.create_#object#() method to generate an ROI on the screen.
However, I could not find a way to get all pixel coordinates inside the
ROI.  I have found that canvas.coors() returns pixel coordinates but
they do not normally form a close contour.  What I was wondering is
whether there is a simple way to get all pixels inside an object that is
created by canvas.create_#object#() method.

I see your suggestion is a possible way: get the bbox() return values
for the object and test each pixel (or a small box) to see whether or
not it is inside the object.  But are there easier and more direct ways
to do this?

Yahui

On Mon, 2011-06-20 at 23:39 -0700, Lion Kimbro wrote:
> 
>   I'm not sure what you mean, but perhaps you are looking for:
> 
> canvas.find_enclosed(x1, y1, x2, y2)     => [objID, objID, ...]
> completely enclosed
> canvas.find_overlapping(x1, y1, x2, y2)  => [objID, objID, ...]
> sharing at least 1 point
> 
>   ..?
> 
> 
> On Mon, Jun 20, 2011 at 7:59 PM, <yahuip at uchicago.edu> wrote:
>         Hi there,
>         
>         I have been struggling to find a way to retrieve all pixel
>         coordinates that are enclosed by an object drawn on a canvas
>         widget.  Anyone knows how I can do it?
>         
>         Thanks,
>         Yahui
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