simplify

fontland/fontland/font.rkt

@@ -5,7 +5,6 @@
          "bbox.rkt"
          "glyphrun.rkt"
          "directory.rkt"
-         "db.rkt"
          "struct.rkt"
          "table-stream.rkt"
          xenomorph
@@ -68,82 +67,31 @@ https://github.com/mbutterick/fontkit/blob/master/src/TTFFont.js
   (+bbox (hash-ref head-table 'xMin) (hash-ref head-table 'yMin)
          (hash-ref head-table 'xMax) (hash-ref head-table 'yMax)))
 
-(define current-layout-caching (make-parameter #false))
-
-(struct hb-gid (val) #:transparent)
-(struct hb-cluster (chars) #:transparent)
-(struct hb-position (xad yad xoff yoff etc) #:transparent)
-(struct hb-layout (hb-gids hb-clusters hb-positions) #:transparent)
-
-(define hb-output (x:struct 'hb-gids (x:array #:type uint16 #:length uint16)
-                            'hb-clusters (x:array #:type (x:array #:type uint16 #:length uint16) #:length uint16)
-                            'hb-positions (x:array #:type (x:array #:type uint16 #:length 5) #:length uint16)))
-
-(define (hb-layout->glyphrun font hbr)
-  (match hbr
-    [(hash-table ('hb-gids gids)
-                 ('hb-clusters clusters)
-                 ('hb-positions posns))
-     (define glyphs (for/list ([gidx (in-list gids)]
-                               [cluster (in-list clusters)])
-                              (get-glyph font gidx cluster)))
-     (define positions (for/list ([posn (in-list posns)])
-                                 (apply +glyph-position posn)))
-     (glyphrun glyphs positions)]))
-
-(define (harfbuzz-layout font codepoints features script language)
+
+;; 181228: disk-based caching (either with sqlite or `with-cache`) is a loser
+;; reads & writes aren't worth it vs. recomputing
+;; (though this is good news, as it avoids massive disk caches hanging around)
+;; ram cache in pitfall suffices
+
+;; todo: preserve semantics of user-features argument from pitfall, which is
+;; #f = no features, null = default features, list = explicit features
+(define (layout font str [features #f] [script #f] [language #f])
   (define buf (hb-buf font))
   (hb_buffer_reset buf)
+  (define codepoints (for/list ([c (in-string str)]) (char->integer c)))
   (hb_buffer_add_codepoints buf codepoints)
   (define chars (map hb_glyph_info_t-codepoint (hb_buffer_get_glyph_infos buf)))
   (hb_shape (hb-font font) buf (map tag->hb-feature (or features null)))
   (define gis (hb_buffer_get_glyph_infos buf))
-  (dictify 'hb-gids (map hb_glyph_info_t-codepoint gis)
-           'hb-clusters (break-at chars (map hb_glyph_info_t-cluster gis))
-           'hb-positions (map hb_glyph_position_t->list (hb_buffer_get_glyph_positions buf))))
-
-(define layout-cache (make-hasheqv))
-
-(define hb-input (x:struct 'font-crc uint32
-                           'codepoints (x:array #:type uint16)
-                           'userFeatures (x:array #:type (x:string #:length uint8))))
-
-(define (layout-cache-key font-crc codepoints user-features . _)
-  (crc32c-bytes (encode hb-input (dictify 
-                                  'font-crc font-crc
-                                  'codepoints codepoints
-                                  'userFeatures user-features) #f)))
-
-
-;; Returns a GlyphRun object, which includes an array of Glyphs and GlyphPositions for the given string.
-(init-db) ; make sure db is ready for queries
-(define (layout font string [user-features #f] [script #f] [language #f] #:test [test #f])
-  #;((string?) ((option/c (listof symbol?)) (option/c symbol?) (option/c symbol?)) . ->*m . GlyphRun?)
-  (define (get-layout string)
-    (define codepoints (map char->integer (string->list string)))
-    (define args (list codepoints (if user-features (sort user-features symbol<?) null) script language))
-    (define key (apply layout-cache-key (ttf-font-crc font) args))
-    (hash-ref! layout-cache key
-               (λ ()
-                 #;(encode hb-output (apply harfbuzz-layout font args) #f)
-                 (match (get-layout-from-db key)
-                   [(? bytes? res) (decode hb-output res)]
-                   [_  (define new-layout (apply harfbuzz-layout font args))
-                       (add-record! (cons key (encode hb-output new-layout #f)))
-                       (make-hasheq new-layout)])))) ;; `dump` converts to hash
-  ;; work on substrs to reuse cached pieces
-  ;; caveat: no shaping / positioning that involve word spaces
-  ;; todo: why does caching produce slightly different results in test files
-  ;; theory: because word space is not included in shaping
-  (cond
-    [(current-layout-caching)
-     (define substrs (for/list ([substr (in-list (regexp-match* " " string #:gap-select? #t))]
-                                #:when (positive? (string-length substr)))
-                               substr))
-     (apply append-glyphruns (map (λ (layout) (hb-layout->glyphrun font layout)) (map get-layout substrs)))]
-    [else (if test
-              (get-layout string)
-              (hb-layout->glyphrun font (get-layout string)))]))
+  (define hb-gids (map hb_glyph_info_t-codepoint gis))
+  (define hb-clusters (break-at chars (map hb_glyph_info_t-cluster gis)))
+  (define hb-positions (map hb_glyph_position_t->list (hb_buffer_get_glyph_positions buf)))
+  (define glyphs (for/vector ([gidx (in-list hb-gids)]
+                            [cluster (in-list hb-clusters)])
+                           (get-glyph font gidx cluster)))
+  (define positions (for/vector ([posn (in-list hb-positions)])
+                              (apply +glyph-position posn)))
+  (glyphrun glyphs positions))
 
 
 #|
@@ -182,7 +130,7 @@ https://github.com/mbutterick/fontkit/blob/master/src/base.js
    (error 'create-font "unknown font format")))
 
 (module+ test
-  (require rackunit)
+  (require rackunit racket/struct)
   (define charter (open-font charter-path))
   (define fira (open-font (path->string fira-path)))
   (define otf (open-font (path->string fira-otf-path)))
@@ -197,11 +145,10 @@ https://github.com/mbutterick/fontkit/blob/master/src/base.js
   (check-equal? (font-cap-height charter) 671)
   (check-equal? (font-x-height charter) 481)
   (check-equal? (bbox->list (font-bbox charter)) '(-161 -236 1193 963))
-  (check-equal? (caar (hash-ref (layout charter "f" #:test #t) 'hb-positions)) 321)
+  (check-equal? (glyph-position-x-advance (car (glyphrun-positions (layout charter "f")))) 321)
   (check-true (has-table? charter #"cmap"))
   (check-exn exn:fail:contract? (λ () (get-table charter 'nonexistent-table-tag)))
   (check-true
-   (let ([h (layout fira "Rifle" #:test #t)])
-     (and (equal? (hash-ref h 'hb-gids) '(227 480 732 412))
-          (equal? (hash-ref h 'hb-clusters) '((82) (105) (102 108) (101)))
-          (equal? (hash-ref h 'hb-positions) '((601 0 0 0 0) (279 0 0 0 0) (580 0 0 0 0) (547 0 0 0 0)))))))
+   (let ([gr (layout fira "Rifle")])
+     (and (equal? (map glyph-id (glyphrun-glyphs gr)) '(227 480 732 412))
+          (equal? (map struct->list (glyphrun-positions gr)) '((601 0 0 0 0) (279 0 0 0 0) (580 0 0 0 0) (547 0 0 0 0)))))))