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Re: can someone help me with the image elisp API
From: |
Andy Moreton |
Subject: |
Re: can someone help me with the image elisp API |
Date: |
Tue, 08 Dec 2015 09:30:41 +0000 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (windows-nt) |
On Mon 07 Dec 2015, Jim Newton wrote:
> I've opened an image (a .png) file in an emacs buffer.
> I'd like to be able to click in the image with the RMB (or any good mouse
> event),
> and somehow relate the point the user clicked to the
> coordinates in the image.
>
> For example, this elisp function gets the x-y position. Suppose it is (609 .
> 41)
> I want to know if that is in the box within the image coordinates
> (( 447.32 199.28) ( 449.7426 199.9871))
>
> I need of course to consider that the user might have scrolled or panned or
> zoomed
> within the image before calling the class-graph-from-click function.
>
> (defun class-graph-from-click (event)
> (interactive "e")
> (let ((position (event-start event)))
> (posn-x-y position) ;; this is the x-y where the mouse was clicked-down
> (message "xy=%s" (posn-x-y position))))
Have a look at the manual at (info "(elisp) Accessing Mouse") which
shows the utility functions provided for handling mouse position data.
It looks like 'posn-image and 'posn-object-x-y position are what you
need.
AndyM