From 56e825cc9e095a456a9a7055afcbb6afe0348d8d Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Wed, 27 Mar 2019 11:05:24 -0700
Subject: [PATCH] tolerate fontlessness

---
 quad/qtest/markdown.rkt | 25 ++++++++++++++++---------
 quad/quad/position.rkt  | 10 ++++++----
 2 files changed, 22 insertions(+), 13 deletions(-)

diff --git a/quad/qtest/markdown.rkt b/quad/qtest/markdown.rkt
index 14526410..fd1361f8 100644
--- a/quad/qtest/markdown.rkt
+++ b/quad/qtest/markdown.rkt
@@ -275,18 +275,25 @@
                                    [substr (in-list (regexp-match* (regexp (string hyphen-char)) hstr #:gap-select? #t))])
                          (struct-copy quad q [elems (list substr)]))]))))
 
+(require sugar/list)
 (define (fill-wrap qs ending-q)
   (match-define (list line-width line-height) (quad-size q:line))
-  (match (quad-ref (car qs) 'line-align #f)
+  ;; todo: how to detect last line of paragraph?
+  (match (and ending-q (pair? qs) (quad-ref (car qs) 'line-align #f))
     ["justify"
-     (define words (for/list ([q (in-list qs)]
-                              #:unless (equal? (car (quad-elems q)) " "))
-                     q))
-     (define words-width (pt-x (apply pt+ (map size words))))
-     (define empty-hspace (- line-width words-width))
-     (define space-width (/ empty-hspace (sub1 (length words))))
-     (add-between words (make-quad #:size (pt space-width line-height)))]
-    [_ qs]))
+     ;; words may still be in hyphenated fragments
+     ;; (though soft hyphens would have been removed)
+     (define word-sublists (filter-split qs (λ (q) (equal? (car (quad-elems q)) " "))))
+     (match (length word-sublists)
+       [1 qs] ; can't justify single word
+       [word-count
+        (define words-width (for*/sum ([word-sublist (in-list word-sublists)]
+                                       [word (in-list word-sublist)])
+                              (pt-x (size word))))
+        (define empty-hspace (- line-width words-width))
+        (define space-width (/ empty-hspace (sub1 word-count)))
+        (apply append (add-between word-sublists (list (make-quad #:size (pt space-width line-height)))))])]
+     [_ qs]))
 
 (define (line-wrap qs wrap-size)
   (wrap qs
diff --git a/quad/quad/position.rkt b/quad/quad/position.rkt
index 6456426f..09c0a3b5 100644
--- a/quad/quad/position.rkt
+++ b/quad/quad/position.rkt
@@ -20,14 +20,14 @@
 
 (define ascender-cache (make-hash))
 (define (ascender q)
-  (define font-key-val (quad-ref q font-path-key "Courier"))
+  (define font-key-val (quad-ref q font-path-key #false))
   (unless font-key-val
     (error 'ascender-no-font-key))
   (hash-ref! ascender-cache font-key-val (λ () (font-ascent (get-font font-key-val)))))
 
 (define units-cache (make-hash))
 (define (units-per-em q)
-  (define font-key-val (quad-ref q font-path-key "Courier"))
+  (define font-key-val (quad-ref q font-path-key #false))
   (unless font-key-val
     (error 'units-per-em-no-font-key))
   (hash-ref! units-cache font-key-val (λ () (font-units-per-em (get-font font-key-val)))))
@@ -38,7 +38,7 @@
 
 (define (vertical-baseline-offset q)
   (cond
-    [(quad-ref q font-path-key #f)
+    [(quad-ref q font-path-key #false)
      (* (/ (ascender q) (units-per-em q) 1.0) (fontsize q))]
     [else 0]))
 
@@ -53,7 +53,9 @@
       [else (raise-argument-error 'anchor->local-point (format "anchor value in ~v" valid-anchors) anchor)]))
   (match-define (list x y) (size q))
   (pt (coerce-int (* x x-fac))
-      (coerce-int (+ (* y y-fac) (if (memq anchor '(bi bo)) (vertical-baseline-offset q) 0)))))
+      (coerce-int (+ (* y y-fac) (match anchor
+                                   [(or 'bi 'bo) (vertical-baseline-offset q)]
+                                   [_ 0])))))
 
 (define (inner-point q)
   ;; calculate absolute location of inner-point