Re: About x_draw_xwidget_glyph_string

[Eli Zaretskii <eliz@gnu.org>]

> From: joakim@verona.se
> Cc: YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp>,  emacs-devel@gnu.org
> Date: Fri, 08 Apr 2016 17:35:23 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> Date: Mon, 25 Jan 2016 11:07:16 +0900
> >> From: YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp>
> >> 
> >> 2. Comment on clipping.
> >> 
> >>    578	  /* Calculate clipping, which is used for all manner of onscreen
> >>    579	     xwidget views.  Each widget border can get clipped by other emacs
> >>    580	     objects so there are four clipping variables.  */
> >>    581	  clip_right =
> >>    582	    min (xww->width,
> >>    583	         WINDOW_RIGHT_EDGE_X (s->w) - x -
> >>    584	         WINDOW_RIGHT_SCROLL_BAR_AREA_WIDTH (s->w) -
> >>    585	         WINDOW_RIGHT_FRINGE_WIDTH (s->w));
> >>    586	  clip_left =
> >>    587	    max (0,
> >>    588	         WINDOW_LEFT_EDGE_X (s->w) - x +
> >>    589	         WINDOW_LEFT_SCROLL_BAR_AREA_WIDTH (s->w) +
> >>    590	         WINDOW_LEFT_FRINGE_WIDTH (s->w));
> >>    591	
> >>    592	  clip_bottom =
> >>    593	    min (xww->height,
> >>    594	         WINDOW_BOTTOM_EDGE_Y (s->w) - WINDOW_MODE_LINE_HEIGHT (s->w) - y);
> >>    595	  clip_top = max (0, WINDOW_TOP_EDGE_Y (s->w) - y);
> >> 
> >> I think the calculation of clipping should use the function window_box
> >> rather than manual calculation with various window macros.  Otherwise,
> >> xwidget views will cover horizontal scroll bars, for example.
> >
> > I agree.
> >
> > Thanks.
> >
> 
> I tried to do this, but I'm doing something wrong. How is window_box
> meant to be used?
> 
> This is my attempt to replace the code above:
> 
>   //JAVE work in progressing, suggested by YAMAMOTO Mitsuharu
>   int text_area_x, text_area_y, text_area_width, text_area_height;
>   
>   window_box (s->w,
>               ANY_AREA, //also tried TEXT_AREA

You should use TEXT_AREA here.

>               &text_area_x,
>               &text_area_y,
>               &text_area_width,
>               &text_area_height);
>   clip_right =
>     min (xww->width,
>          text_area_width);
>   clip_left =
>     max (0,
>          text_area_x);
> 
>   clip_bottom =
>     min (xww->height,
>          text_area_y);
>   clip_top = max (0, text_area_height);

I think clip_top should use text_area_y and clip_bottom should use
text_area_height.

Other than those two issues, what other problems do you see?