Function: posn-at-x-y

posn-at-x-y is a function defined in keyboard.c.

Signature

(posn-at-x-y X Y &optional FRAME-OR-WINDOW WHOLE)

Documentation

Return position information for pixel coordinates X and Y.

By default, X and Y are relative to text area of the selected window. Note that the text area includes the header-line and the tab-line of the window, if any of them are present. Optional third arg FRAME-OR-WINDOW non-nil specifies frame or window. If optional fourth arg WHOLE is non-nil, X is relative to the left edge of the window.

The return value is similar to a mouse click position:
   (WINDOW AREA-OR-POS (X . Y) TIMESTAMP OBJECT POS (COL . ROW)
    IMAGE (DX . DY) (WIDTH . HEIGHT))
The posn- functions access elements of such lists.

Probably introduced at or before Emacs version 22.1.

Source Code

// Defined in /usr/src/emacs/src/keyboard.c
{
  CHECK_FIXNUM (x);
  /* We allow X of -1, for the newline in a R2L line that overflowed
     into the left fringe.  */
  if (XFIXNUM (x) != -1)
    CHECK_FIXNAT (x);
  CHECK_FIXNAT (y);

  if (NILP (frame_or_window))
    frame_or_window = selected_window;

  if (WINDOWP (frame_or_window))
    {
      struct window *w = decode_live_window (frame_or_window);

      XSETINT (x, (XFIXNUM (x)
		   + WINDOW_LEFT_EDGE_X (w)
		   + (NILP (whole)
		      ? window_box_left_offset (w, TEXT_AREA)
		      : 0)));
      XSETINT (y, WINDOW_TO_FRAME_PIXEL_Y (w, XFIXNUM (y)));
      frame_or_window = w->frame;
    }

  CHECK_LIVE_FRAME (frame_or_window);

  return make_lispy_position (XFRAME (frame_or_window), x, y, 0);
}