Subject: bug#8863: 23.3; Strikethrough won't display on MacOS

From: Dave Abrahams <[email-masked]>
Date: Fri, 01 Jul 2011 22:03:12 -0400

on Sat Jun 18 2011, Chong Yidong <cyd-AT-stupidchicken.com> wrote:

> Dave Abrahams <[email-masked]> writes:
>
>> Title says it all.  Faces with the "strikethrough" property set show up
>> as un-struck-through.
>
> Does this (100% untested) patch do the right thing?
>
> *** src/nsfont.m	2011-01-02 23:50:46 +0000
> --- src/nsfont.m	2011-06-18 21:48:28 +0000
> ***************
> *** 1188,1193 ****
> --- 1188,1207 ----
>   /*[context GSSetTextDrawingMode: GSTextFill]; /// not implemented yet */
>         }
>   
> +     /* do strike-through */
> +     if (face->strike_through_p)
> +       {
> + 	float line_y = r.origin.y - 0.5 * font->height;
> +         if (face->strike_through_color != 0)
> +           [ns_lookup_indexed_color (face->strike_through_color, s->f) set];
> +         else
> +           [col set];
> +         DPSmoveto (context, r.origin.x, line_y);
> +         DPSlineto (context, r.origin.x + r.size.width, line_y);
> +         if (face->strike_through_color != 0)
> +           [col set];
> +       }
> + 
>       /* do underline */
>       if (face->underline_p)
>         {

No, but the enclosed 2 patches, together, seem to.  Would somebody apply
these, please?

--- src/nsterm.h	2011-01-08 17:45:14.000000000 +0000
+++ src/nsterm.h	2011-07-02 01:46:06.000000000 +0000
@@ -435,6 +435,7 @@
   char bold, ital;  /* convenience flags */
   char synthItal;
   float voffset;  /* mean of ascender/descender offsets */
+  float xheight;  /* used to position the strikethrough line */
   XCharStruct max_bounds;
   /* we compute glyph codes and metrics on-demand in blocks of 256 indexed
      by hibyte, lobyte */
--- src/nsfont.m.old	2011-07-02 01:52:29.000000000 +0000
+++ src/nsfont.m	2011-07-02 01:53:51.000000000 +0000
@@ -840,6 +840,7 @@
     font_info->underwidth = [sfont underlineThickness];
     font_info->size = font->pixel_size;
     font_info->voffset = lrint (hshrink * [sfont ascender] + expand * hd / 2);
+    font_info->xheight = lrint (hshrink * [sfont xHeight] + expand * hd / 2);
 
     /* max bounds */
     font_info->max_bounds.ascent =
@@ -1188,6 +1189,22 @@
 /*[context GSSetTextDrawingMode: GSTextFill]; /// not implemented yet */
       }
 
+    /* do strike-through */
+    if (face->strike_through_p)
+      {
+	 float line_y = lrint (r.origin.y - 0.5 * font->xheight);
+        if (face->strike_through_color != 0)
+          [ns_lookup_indexed_color (face->strike_through_color, s->f) set];
+        else
+          [col set];
+        DPSmoveto (context, r.origin.x, line_y);
+        DPSlineto (context, r.origin.x + r.size.width, line_y);
+        if (face->strike_through_color != 0)
+          [col set];
+      }
+    else 
+     [col set];
+
     /* do underline */
     if (face->underline_p)
       {
@@ -1248,6 +1265,23 @@
         CGContextSetTextDrawingMode (gcontext, kCGTextFill);
       }
 
+    if (face->strike_through_p)
+      {
+	 float line_y = lrint (r.origin.y - 0.5 * font->xheight);
+        if (face->strike_through_color != 0)
+          [ns_lookup_indexed_color (face->strike_through_color, s->f) set];
+        else
+          [col set];
+        CGContextBeginPath (gcontext);
+        CGContextMoveToPoint (gcontext, r.origin.x, line_y);
+        CGContextAddLineToPoint (gcontext, r.origin.x + r.size.width, line_y);
+        CGContextStrokePath (gcontext);
+        if (face->strike_through_color != 0)
+          [col set];
+      }
+    else
+      [col set];
+
     if (face->underline_p)
       {
         if (face->underline_color != 0)

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com