Re: [Matplotlib-users] How to find out the extend of the actual image in pixels

[Alexander D. <ale...@go...>]

Hi,

On Wed, Sep 29, 2010 at 16:00, John Hunter <jd...@gm...> wrote:

> On Wed, Sep 29, 2010 at 8:50 AM, Alexander Dietz
> <Ale...@go...> wrote:
>
> > print ax.transData.transform((10.0, 20.0))
> > [ 576.  432.]
>
>
> Why do you say it's wrong?  Note that in mpl, (0,0) is (bottom left),
> not (upper,left).  So this is saying that the yellow dot at 10,20
> (data coords) is 576 pixels up from the bottom and 432 pixels over
> from the left.
>

This is not correct, either. Since the total width of the image is 800
pixels and the total height is 600 pixels, I get the following coordinates
of the yellow dot:

x-coord: = 432
y-coord = 600-576 = 24

but in fact, the position of the yellow dot is still at (720, 60)!. (And
even if you swapped x and y coordinates it will never be correct.).


So anyone another idea how to transform a data-point (10,20) to the image
coordinates?


Cheers
  Alex



>
> JDH
>