lstopo/fig: import the generic textsize method code

fig was the only backend without a textsize callback.
Move the generic fallback code to the backend so that we can tune it,
and enforce the existence of that method in the core.

Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>

utils/lstopo/lstopo-draw.c

@@ -135,12 +135,13 @@ get_textwidth(void *output,
 	      unsigned fontsize)
 {
   struct lstopo_output *loutput = output;
-  if (loutput->methods->textsize) {
-    unsigned width;
-    loutput->methods->textsize(output, text, length, fontsize, &width);
-    return width;
-  }
-  return (length * fontsize * 3) / 4;
+  unsigned width;
+
+#ifdef HWLOC_DEBUG
+  assert(loutput->methods->textsize);
+#endif
+  loutput->methods->textsize(output, text, length, fontsize, &width);
+  return width;
 }
 
 /* preferred width/height compromise */

utils/lstopo/lstopo-fig.c

@@ -92,12 +92,18 @@ fig_text(struct lstopo_output *loutput, const struct lstopo_color *lcolor, int s
   fprintf(file, "4 0 %d %u -1 0 %d 0.0 4 %d %d %u %u %s\\001\n", color, depth, size, size * 10, len * size * 10, x, y + size * 10, text);
 }
 
+static void
+fig_textsize(struct lstopo_output *loutput __hwloc_attribute_unused, const char *text __hwloc_attribute_unused, unsigned textlength, unsigned fontsize, unsigned *width)
+{
+  *width = (textlength * fontsize * 3) / 4;
+}
+
 static struct draw_methods fig_draw_methods = {
   fig_declare_color,
   fig_box,
   fig_line,
   fig_text,
-  NULL, /* textsize not supported, fallback to default estimation in get_textsize() */
+  fig_textsize,
 };
 
 int