如何获得emacs模式行的高度？

Question

Actually, I want to generate a XPM-format image and draw it on the mode line using display attribute of a text string. However, the height of mode line turns to be different as the result of different fontset.

That means I need to know the height of the emacs mode line and use it to generate the corresponding size of the XPM-format image, so that the generated image can fill the mode line totally.

My question is just showing as the title, how can i know the actually (finally rendered) height of the mode line after applying a specific fontset?

I have searched the emacs documentation via apropos , what I found now is:
I can use the font-info function to get the font height in current frame. I guess maybe I can get what I want based on this, although I am unlucky until now.

And, I cannot find any function related a the mode line height.

Answer 1

Try

(- (elt (window-pixel-edges) 3) 
   (elt (window-inside-pixel-edges) 3))