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From: fgreco@dprg-330.GOVt.shearson.COM (Frank Greco)
Newsgroups: comp.windows.x
Subject: Re: XView textsw question
Message-ID: <9012241529.AA21480@fis1.>
Date: 24 Dec 90 15:29:28 GMT
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 37


> 
> I am interposing a Text Subwindow to catch mouse events in the window. In
> the interposing function how can I calculate the mouse location in terms of
> a character index or line index in the Text Subwindow?
> 

	This is determined from the XY of the mouse and the font dimensions 
	(mostly just the font height) of the TEXTSW's font.


	e.g., To get the on-screen line number, call this little
	ditty from your event proc, passing the view and the mouse XY.

	int getscreenline(tswv, x, y)
	Textsw tswv;			/* Which text subwindow (view) */
	int x, y;			/* Coordinates of mouse */
	{
		Xv_font font;		/* Font of the textsw */
		Font_string_dims strdims;

		if ( !(font = (Xv_font) xv_get(tswv, TEXTSW_FONT)) )
			return -1;

		(void) xv_get(font, FONT_STRING_DIMS, "abcde", &strdims);

		return y / strdims.height;
	}


	Of course, you add the line # of the first viewable line in the
	TEXTSW to this number to get the overall line #.

	Getting the character index is done similarly.


	Frank G.