From 9e6c9c57f3c03ac7112342f8dd0c7f9937a2bbcc Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Thu, 27 Dec 2018 10:31:07 -0800
Subject: [PATCH] finish structifying font

---
 pitfall/pitfall/embedded-font.rkt | 310 +++++++++++++++---------------
 pitfall/pitfall/fonts.rkt         |   7 +-
 pitfall/pitfall/standard-font.rkt |   2 -
 3 files changed, 160 insertions(+), 159 deletions(-)

diff --git a/pitfall/pitfall/embedded-font.rkt b/pitfall/pitfall/embedded-font.rkt
index ae949d5e..befe82b7 100644
--- a/pitfall/pitfall/embedded-font.rkt
+++ b/pitfall/pitfall/embedded-font.rkt
@@ -3,15 +3,14 @@
   (for-syntax racket/base)
   "core.rkt"
   "reference.rkt"
-  racket/class
   racket/match
   racket/string
   racket/format
   racket/list
   racket/dict
   sugar/unstable/dict
-  "font.rkt"
   fontland)
+(provide make-embedded-font)
 
 #|
 approximates
@@ -31,142 +30,149 @@ https://github.com/mbutterick/pdfkit/blob/master/lib/font/embedded.coffee
    (for/list ([code (in-list codePoints)])
      (~r code #:base 16 #:min-width 4 #:pad-string "0"))))
 
-#;(define EmbeddedFont
-  (class PDFFont
-    (init-field font id)
-    (field [subset (create-subset font)]
-           ;; we make `unicode` and `width` fields integer-keyed hashes not lists
-           ;; because they offer better random access and growability 
-           [unicode (mhash 0 '(0))] ; always include the missing glyph (gid = 0)
-           [widths (mhash 0 (glyph-advance-width (get-glyph font 0)))]
-           ;; always include the width of the missing glyph (gid = 0)
-           [name (font-postscript-name font)]
-           [scale (/ 1000 (font-units-per-em font))])
-    (super-new [ascender (* (font-ascent font) scale)]
-               [descender (* (font-descent font) scale)]
-               [bbox (font-bbox font)]
-               [line-gap (* (font-linegap font) scale)])
-
-    (inherit-field [@ascender ascender]
-                   [@descender descender]
-                   [@dictionary dictionary])
-
-    (define/override (string-width string size [features #f])
-      ; #f disables features ; null enables default features ; list adds features
-      (hash-ref! width-cache
-                 (list string size (and features (sort features symbol<?)))
-                 (λ ()
-                   (define run (layout font string features))
-                   (define width (glyphrun-advance-width run))
-                   (define scale (/ size (+ (font-units-per-em font) 0.0)))
-                   (* width scale))))
-
-    ;; called from text.rkt
-    (define/override (encode text [features #f])
-      (define glyphRun (layout font text features))
-      (define glyphs (glyphrun-glyphs glyphRun))
-      (define positions (glyphrun-positions glyphRun))
-      (define-values (subset-idxs new-positions)
-        (for/lists (idxs posns)
-                   ([(g i) (in-indexed glyphs)]
-                    [posn (in-list positions)])
-          (define gid (subset-add-glyph! subset (glyph-id g)))
-          (define subset-idx (to-hex gid))
-          (set-glyph-position-advance-width! posn (glyph-advance-width g))
-
-          (hash-ref! widths gid (λ () (glyph-position-advance-width posn)))
-          (hash-ref! unicode gid (λ () (glyph-codepoints g)))
-
-          (scale-glyph-position! posn scale)
-          (values subset-idx posn)))
-      (list subset-idxs new-positions))
-
-
-    (define/override (embed)
-      ;; no CFF support
-      (define isCFF #false) #;(is-a? subset CFFSubset)
-      (define font-file (make-ref))
-
-      (when isCFF
-        (dict-set! font-file 'Subtype 'CIDFontType0C))
-
-      (ref-write font-file (get-output-bytes (encode-to-port subset)))
-      (ref-end font-file)
-
-      (define family-class (if (has-table? font 'OS/2)
-                               (floor (/ (hash-ref (get-OS/2-table font) 'sFamilyClass) 256)) ; >> 8
-                               0))
-      ;; font descriptor flags
-      (match-define (list FIXED_PITCH SERIF SYMBOLIC SCRIPT _UNUSED NONSYMBOLIC ITALIC)
-        (map (λ (x) (expt 2 x)) (range 7)))
-
-      (define flags (sum-flags
-                     [(not (zero? (hash-ref (get-post-table font) 'isFixedPitch))) FIXED_PITCH]
-                     [(<= 1 family-class 7) SERIF]
-                     [#t SYMBOLIC] ; assume the font uses non-latin characters
-                     [(= family-class 10) SCRIPT]
-                     [(hash-ref (hash-ref (get-head-table font) 'macStyle) 'italic) ITALIC]))
-
-      ;; generate a random tag (6 uppercase letters. 65 is the char code for 'A')
-      (when (test-mode) (random-seed 0))
-      (define tag (list->string (for/list ([i (in-range 6)])
-                                  (integer->char (random 65 (+ 65 26))))))
-      (define name (string->symbol (string-append tag "+" (font-postscript-name font))))
-      (define bbox (font-bbox font))
-      (define descriptor (make-ref
-                          (mhash
-                           'Type 'FontDescriptor
-                           'FontName name
-                           'Flags flags
-                           'FontBBox (map (λ (x) (* scale x))
-                                          (bbox->list bbox))
-                           'ItalicAngle (font-italic-angle font)
-                           'Ascent @ascender
-                           'Descent @descender
-                           'CapHeight (* (or (font-cap-height font) (font-ascent font)) scale)
-                           'XHeight (* (or (font-x-height font) 0) scale)
-                           'StemV 0)))
-
-      (dict-set! descriptor (if isCFF 'FontFile3 'FontFile2) font-file)
-      (ref-end descriptor)
-
-      (define descendant-font (make-ref
-                               (mhash
-                                'Type 'Font
-                                'Subtype (string->symbol (string-append "CIDFontType" (if isCFF "0" "2")))
-                                'BaseFont name
-                                'CIDSystemInfo
-                                (mhash
-                                 'Registry "Adobe"
-                                 'Ordering "Identity"
-                                 'Supplement 0)
-                                'FontDescriptor descriptor
-                                'W (list 0 (for/list ([idx (in-range (length (hash-keys widths)))])
-                                             (hash-ref widths idx (λ () (error 'embed (format "hash key ~a not found" idx)))))))))
-      (ref-end descendant-font)
+(struct $embedded-font $font (font subset unicode widths scale) #:mutable)
+
+(define (make-embedded-font font id)
+  [define subset (create-subset font)]
+  ;; we make `unicode` and `width` fields integer-keyed hashes not lists
+  ;; because they offer better random access and growability 
+  [define unicode (mhasheqv 0 '(0))] ; always include the missing glyph (gid = 0)
+  [define widths (mhasheqv 0 (glyph-advance-width (get-glyph font 0)))]
+  ;; always include the width of the missing glyph (gid = 0)
+  [define name (font-postscript-name font)]
+  [define scale (/ 1000 (font-units-per-em font))]
+  [define ascender (* (font-ascent font) scale)]
+  [define descender (* (font-descent font) scale)]
+  [define bbox (font-bbox font)]
+  [define line-gap (* (font-linegap font) scale)]
+  (define new-font
+    ($embedded-font name id ascender descender line-gap bbox
+                    #f ; no dictionary
+                    #f ; not embedded
+                    'embfont-embed-placeholder 'embfont-encode-placeholder 'embfont-string-width-placeholder
+                    font subset unicode widths scale))
+  (define (embed-proc) (embfont-embed new-font))
+  (set-$font-embed-proc! new-font embed-proc)
+  (define (encode-proc str [options #f]) (embfont-encode new-font str options))
+  (set-$font-encode-proc! new-font encode-proc)
+  (define (string-width-proc str size [options #f]) (embfont-string-width new-font str size options))
+  (set-$font-string-width-proc! new-font string-width-proc)
+  new-font)
+
+(define (embfont-embed font)
+  ;; no CFF support
+  
+  (define isCFF #false) #;(is-a? subset CFFSubset)
+  (define font-file (make-ref))
+
+  (when isCFF
+    (dict-set! font-file 'Subtype 'CIDFontType0C))
+
+  (ref-write font-file (get-output-bytes (encode-to-port ($embedded-font-subset font))))
+  (ref-end font-file)
+
+  (define family-class (if (has-table? ($embedded-font-font font) 'OS/2)
+                           (floor (/ (hash-ref (get-OS/2-table ($embedded-font-font font)) 'sFamilyClass) 256)) ; >> 8
+                           0))
+  ;; font descriptor flags
+  (match-define (list FIXED_PITCH SERIF SYMBOLIC SCRIPT _UNUSED NONSYMBOLIC ITALIC)
+    (map (λ (x) (expt 2 x)) (range 7)))
+
+  (define flags (sum-flags
+                 [(not (zero? (hash-ref (get-post-table ($embedded-font-font font)) 'isFixedPitch))) FIXED_PITCH]
+                 [(<= 1 family-class 7) SERIF]
+                 [#t SYMBOLIC] ; assume the font uses non-latin characters
+                 [(= family-class 10) SCRIPT]
+                 [(hash-ref (hash-ref (get-head-table ($embedded-font-font font)) 'macStyle) 'italic) ITALIC]))
+
+  ;; generate a random tag (6 uppercase letters. 65 is the char code for 'A')
+  (when (test-mode) (random-seed 0))
+  (define tag (list->string (for/list ([i (in-range 6)])
+                              (integer->char (random 65 (+ 65 26))))))
+  (define name (string->symbol (string-append tag "+" (font-postscript-name ($embedded-font-font font)))))
+  (define bbox (font-bbox ($embedded-font-font font)))
+  (define descriptor (make-ref
+                      (mhash
+                       'Type 'FontDescriptor
+                       'FontName name
+                       'Flags flags
+                       'FontBBox (map (λ (x) (* ($embedded-font-scale font) x))
+                                      (bbox->list bbox))
+                       'ItalicAngle (font-italic-angle ($embedded-font-font font))
+                       'Ascent ($font-ascender font)
+                       'Descent ($font-descender font)
+                       'CapHeight (* (or (font-cap-height ($embedded-font-font font)) (font-ascent ($embedded-font-font font))) ($embedded-font-scale font))
+                       'XHeight (* (or (font-x-height ($embedded-font-font font)) 0) ($embedded-font-scale font))
+                       'StemV 0)))
+
+  (dict-set! descriptor (if isCFF 'FontFile3 'FontFile2) font-file)
+  (ref-end descriptor)
+
+  (define descendant-font (make-ref
+                           (mhash
+                            'Type 'Font
+                            'Subtype (string->symbol (string-append "CIDFontType" (if isCFF "0" "2")))
+                            'BaseFont name
+                            'CIDSystemInfo
+                            (mhash
+                             'Registry "Adobe"
+                             'Ordering "Identity"
+                             'Supplement 0)
+                            'FontDescriptor descriptor
+                            'W (list 0 (for/list ([idx (in-range (length (hash-keys ($embedded-font-widths font))))])
+                                         (hash-ref ($embedded-font-widths font) idx (λ () (error 'embed (format "hash key ~a not found" idx)))))))))
+  (ref-end descendant-font)
       
-      [dict-set! @dictionary 'Type 'Font]
-      [dict-set! @dictionary 'Subtype 'Type0]
-      [dict-set! @dictionary 'BaseFont name]
-      [dict-set! @dictionary 'Encoding 'Identity-H]
-      [dict-set! @dictionary 'DescendantFonts (list descendant-font)]
-      [dict-set! @dictionary 'ToUnicode (toUnicodeCmap)]
-
-      (ref-end @dictionary))
-
-
-    (define/public (toUnicodeCmap)
-      (define cmap (make-ref))
-      (define entries
-        (for/list ([idx (in-range (length (hash-keys unicode)))])
-          (define codepoints (hash-ref unicode idx))
-          (define encoded ; encode codePoints to utf16
-            ;; todo: full utf16 support. for now just utf8
-            (for/list ([value (in-list codepoints)])
-              (to-hex value)))
-          (format "<~a>" (string-join encoded " "))))
-
-      (define unicode-cmap-str #<<HERE
+  [dict-set! ($font-dictionary font) 'Type 'Font]
+  [dict-set! ($font-dictionary font) 'Subtype 'Type0]
+  [dict-set! ($font-dictionary font) 'BaseFont name]
+  [dict-set! ($font-dictionary font) 'Encoding 'Identity-H]
+  [dict-set! ($font-dictionary font) 'DescendantFonts (list descendant-font)]
+  [dict-set! ($font-dictionary font) 'ToUnicode (to-unicode-cmap font)]
+
+  (ref-end ($font-dictionary font)))
+
+(define (embfont-encode font text [features #f])
+  (define glyphRun (layout ($embedded-font-font font) text features))
+  (define glyphs (glyphrun-glyphs glyphRun))
+  (define positions (glyphrun-positions glyphRun))
+  (define-values (subset-idxs new-positions)
+    (for/lists (idxs posns)
+               ([(g i) (in-indexed glyphs)]
+                [posn (in-list positions)])
+      (define gid (subset-add-glyph! ($embedded-font-subset font) (glyph-id g)))
+      (define subset-idx (to-hex gid))
+      (set-glyph-position-advance-width! posn (glyph-advance-width g))
+
+      (hash-ref! ($embedded-font-widths font) gid (λ () (glyph-position-advance-width posn)))
+      (hash-ref! ($embedded-font-unicode font) gid (λ () (glyph-codepoints g)))
+
+      (scale-glyph-position! posn ($embedded-font-scale font))
+      (values subset-idx posn)))
+  (list subset-idxs new-positions))
+
+(define (embfont-string-width font string size [features #f])
+  ; #f disables features ; null enables default features ; list adds features
+  (hash-ref! width-cache
+             (list string size (and features (sort features symbol<?)))
+             (λ ()
+               (define run (layout ($embedded-font-font font) string features))
+               (define width (glyphrun-advance-width run))
+               (define scale (/ size (+ (font-units-per-em ($embedded-font-font font)) 0.0)))
+               (* width scale))))
+
+(define (to-unicode-cmap font)
+  (define cmap (make-ref))
+  (define entries
+    (for/list ([idx (in-range (length (hash-keys ($embedded-font-unicode font))))])
+      (define codepoints (hash-ref ($embedded-font-unicode font) idx))
+      (define encoded ; encode codePoints to utf16
+        ;; todo: full utf16 support. for now just utf8
+        (for/list ([value (in-list codepoints)])
+          (to-hex value)))
+      (format "<~a>" (string-join encoded " "))))
+
+  (define unicode-cmap-str #<<HERE
 /CIDInit /ProcSet findresource begin
 12 dict begin
 begincmap
@@ -188,21 +194,21 @@ CMapName currentdict /CMap defineresource pop
 end
 end
 HERE
-        )
+    )
   
-      (ref-write cmap (format unicode-cmap-str (to-hex (sub1 (length entries))) (string-join entries " ")))
-      (ref-end cmap)
-      cmap)))
+  (ref-write cmap (format unicode-cmap-str (to-hex (sub1 (length entries))) (string-join entries " ")))
+  (ref-end cmap)
+  cmap)
 
 #;(module+ test
-  (require rackunit fontland sugar/unstable/js)
-  (define f (open-font "../ptest/assets/charter.ttf"))
-  (define ef (make-object EmbeddedFont #f f #f))
-  (check-equal? (send ef string-width "f" 1000) 321.0)
-  (check-equal? (· ef ascender) 980)
-  (check-equal? (· ef descender) -238)
-  (check-equal? (· ef line-gap) 0)
-  (check-equal? (bbox->list (· ef bbox)) '(-161 -236 1193 963))
-  (define H-gid 41)
-  (check-equal? (· ef widths) (mhash 0 278))
-  (check-equal? (glyph-advance-width (get-glyph (· ef font) H-gid)) 738))
\ No newline at end of file
+    (require rackunit fontland sugar/unstable/js)
+    (define f (open-font "../ptest/assets/charter.ttf"))
+    (define ef (make-object EmbeddedFont #f f #f))
+    (check-equal? (send ef string-width "f" 1000) 321.0)
+    (check-equal? (· ef ascender) 980)
+    (check-equal? (· ef descender) -238)
+    (check-equal? (· ef line-gap) 0)
+    (check-equal? (bbox->list (· ef bbox)) '(-161 -236 1193 963))
+    (define H-gid 41)
+    (check-equal? (· ef widths) (mhash 0 278))
+    (check-equal? (glyph-advance-width (get-glyph (· ef font) H-gid)) 738))
\ No newline at end of file
diff --git a/pitfall/pitfall/fonts.rkt b/pitfall/pitfall/fonts.rkt
index 43bd7ed7..42aa3d1f 100644
--- a/pitfall/pitfall/fonts.rkt
+++ b/pitfall/pitfall/fonts.rkt
@@ -4,15 +4,12 @@
   "reference.rkt"
   racket/match
   sugar/unstable/dict
-  racket/class
   "standard-font.rkt"
-  "font.rkt"
   fontland
   "embedded-font.rkt")
 
 (provide (all-defined-out))
 
-
 (define (make-font-ref font)
   (unless ($font-dictionary font)
     (set-$font-dictionary! font (make-ref)))
@@ -30,14 +27,14 @@
 (define (PDFFont-open src family id)
   (cond
     [(and (string? src) (standard-font? src)) (make-standard-font src id)]
-    #;[else
+    [else
      (define font
        (cond
          [(string? src) (open-font src)]
          [(path? src) (open-font (path->string src))]
          ;; todo: other font-loading cases
          [else (raise-argument-error 'PDFFont-open "loadable font thingy" src)]))
-     (make-object EmbeddedFont font id)]))
+     (make-embedded-font font id)]))
 
 
 (define (current-line-height doc [include-gap #f])
diff --git a/pitfall/pitfall/standard-font.rkt b/pitfall/pitfall/standard-font.rkt
index 80ed614a..19747f8e 100644
--- a/pitfall/pitfall/standard-font.rkt
+++ b/pitfall/pitfall/standard-font.rkt
@@ -1,10 +1,8 @@
 #lang racket/base
 (require
-  racket/class
   racket/string
   racket/match
   sugar/unstable/dict
-  "font.rkt"
   "core.rkt"
   "reference.rkt"
   fontland