pict: repairs for line numbering and "paragraph" text alignment

Bring line-number styling closer to Scribble styling. Also, text
alignment via `beside` with `~attach: #'paragraph` did not work right
for scaled picts.

Author: mflatt

rhombus-pict-lib/rhombus/pict/private/last.rhm

@@ -60,8 +60,17 @@ fun
     let last_handle = rkt.#{pict-last}(h1)
     if last_handle
     | let (x, y) = rkt.#{lt-find}(h1, last_handle)
+      let (x2, y2) = rkt.#{rb-find}(h1, last_handle)
       let last_p = path_end(last_handle)
-      let last_p_distinct = rkt.inset(last_p, 0, 0, 0, 0)
+      let lw = rkt.#{pict-width}(last_p)
+      let lh = rkt.#{pict-height}(last_p)
+      let last_p_distinct = rkt.scale(rkt.inset(last_p, 0, 0, 0, 0),
+                                      if lw .= 0
+                                      | 1
+                                      | (x2 - x) / lw,
+                                      if lh .= 0
+                                      | 1
+                                      | (y2 - y) / lh)
       let h2_distinct = rkt.inset(h2, 0, 0, 0, 0)
       let p = rkt_append(sep, last_p_distinct, h2_distinct)
       let (ldx, ldy) = rkt.#{lt-find}(p, last_p_distinct)

rhombus-pict-lib/rhombus/pict/rhombus.rhm

@@ -1,5 +1,6 @@
 #lang rhombus/static/and_meta
 import:
+  rhombus/rx open
   pict open
   pict/text open
   shrubbery/render
@@ -38,18 +39,28 @@ fun rtt(str_s) :~ Pict:
 def (render_line,
      render_block):
   @render.make(~render:
-                 fun (kind, str):
+                 fun (kind, str :~ String):
                    let p :~ Pict:
-                     if kind == #'variable
-                     | italicly: rtt(str)
-                     | rtt(str)
+                     match kind
+                     | #'variable:
+                         italicly: rtt(str)
+                     | #'lineno:
+                         recur loop (str :~ String = str ++ " "):
+                           match rx'" "+'.match_range_in(str)
+                           | RXMatch(s..e, _, _):
+                               beside.baseline(loop(str.substring(0..s)),
+                                               tt(str.substring(s..e)),
+                                               loop(str.substring(e..str.length())))
+                           | ~else: t(str)
+                     | ~else:
+                         rtt(str)
                    match current_rhombus_colorize() && kind
                    | #'value: p.colorize(current_literal_color())
                    | #'result: p.colorize(current_result_color())
                    | #'identifier || #'plain: p.colorize(current_identifier_color())
                    | #'paren: p.colorize(current_paren_color())
                    | #'comment: p.colorize(current_comment_color())
-                   | #'lineno: beside.baseline(p.colorize("blue").scale(0.8), rtt(" "))
+                   | #'lineno: p.colorize("blue").scale(0.8)
                    | ~else: p
                ~render_in_space:
                  fun (space, str, od,