[comp.windows.x] XView textsw question

straw@cam.nist.gov (Mike Strawbridge) (12/21/90)

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?

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barnett@grymoire.crd.ge.com (Bruce Barnett) (12/21/90)

In article <6336@pizza.cam.nist.gov> straw@cam.nist.gov (Mike Strawbridge) writes:

>   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?

My xvttool program (on titan.rice.edu) does this. If you type
Control-LeftButton, it sends a special sequence to the program running
in the tty window. The client understands the escape sequence and
positions the cursor at the location of the mouse click. (The only
client that understands this so far is Mike Gerard's 3270 emulator)

Here is the appropriate code. - first get the height and width of the font.

	font_height = (int)xv_get (terminal_sw, WIN_ROW_HEIGHT);
	font_width = (int)xv_get (terminal_sw, WIN_COLUMN_WIDTH);
	if ( debug && verbose ) 
	  Fprintf(console," Pixel Width: %d, height: %d\n", 
		  font_width, font_height);

and in the event handler: (The || is because of a
different between OW 2.0 pre-fcs and OW 2.0)

    if (event_is_button(event) && 
	(event_left_is_down(event) || (event_id(event) == BUT(1))) &&
	event_ctrl_is_down (event)  ) { 
	column = (event_x(event) / font_width); 
	/* the first line would be 0 - we'll add one to it */
	line = (event_y(event) / font_height) +1;
	if (debug) Fprintf(console, "Mouse at [%d(%d),%d(%d)]\n",
			   line, event_y(event), column, event_x(event));


--
Bruce G. Barnett	barnett@crd.ge.com	uunet!crdgw1!barnett

fgreco@dprg-330.GOVt.shearson.COM (Frank Greco) (12/24/90)

> 
> 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.