tkinter canvas

[John McMonagle]

On Tue, 2006-04-04 at 14:47 -0700, fxe wrote:
> Hi,
>   I am using tkinter and I have a canvas that with several rectangles drawn
> on it. The rectangles need to have bindings to move and resize them. No
> problem here, but I also need to display a grid on the same canvas, for
> which I am using create_line. My problem is I do not want the grid lines to
> be able to move and resize .
> 
> Is this doable or any suggestions on an alternative.Maybe another way to
> display my grid on top of the canvas?
> 

When you create your canvas items use the tags option to differentiate
items you wish to group together.

For example, 

canvas.create_line(x1,y1,x2,y2,fill='#000000',tags='grid')

canvas.create_rectangle(x1,y1,x2,y2,fill='#FF0000',outline='#FF0000',tags='rect')

You can ensure that the grid lines are always displayed below the
rectangles by using the tag_lower method:

canvas.tag_lower('grid', 'rect')

You can bind events to the named tags rather than the canvas as a whole:

canvas.tag_bind('rect', '<Button-1>', startMove)
canvas.tag_bind('rect', '<Button1-Motion>', moveRect)
canvas.tag_bind('rect', '<Button1-ButtonRelease>', finishMove)

Now when you click on a canvas item with a 'grid' tag nothing will
happen, but if you click on a canvas item with a 'rect' tag you will
invoke the appropriate function.

HTH,

John McMonagle



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