show() and dpi settings - suggestion for better rendering

Hi, The logic for displaying a figure on the interactive

    > backends (eg qt) seems a little strange to me. I imagine
    > that normally the screen is used as a preview for a figure
    > that is going to be output on paper, or to png or some
    > permanent store. Therefore, the interactive output should
    > resemble the permanent output as much as possible.

    > Now, when using the QtAgg backend (sorry no time to play
    > with other backends) setting the figure height or width has
    > no effect on the size of the figure displayed with show().
    > It always comes out at 600x400.

Typically you want saved images to be at a higher resolution than the
one on the screen, since most screens are less than 1500x1500 and
often you want a higher resolution setting. That is why the savefig
command takes a dpi parameter, which default to the settin in your rc
file. You could make the screen dpi and the savefig dpi the same in
rc if you want.

I find that when I resize a figure in the GUI window, the aspect ratio
*is* preserved when I save, so the suggestion above should suffice for