resume in layout-engine, ot-layout-engine

pitfall/fontkit/default-shaper.rkt

@@ -0,0 +1,43 @@
+#lang fontkit/racket
+(provide (all-defined-out))
+
+(define VARIATION_FEATURES '(rvrn))
+(define COMMON_FEATURES '(ccmp locl rlig mark mkmk))
+(define FRACTIONAL_FEATURES '(frac numr dnom))
+(define HORIZONTAL_FEATURES '(calt clig liga rclt curs kern))
+(define VERTICAL_FEATURES '(vert))
+(define DIRECTIONAL_FEATURES (mhasheq
+                              'ltr '(ltra ltrm)
+                              'rtl '(rtla rtlm)))
+
+(define zeroMarkWidths 'AFTER_GPOS)
+
+(define-subclass object% (DefaultShaper)
+  
+  (define/public (plan plan_ glyphs features)
+    ;; Plan the features we want to apply
+    (planPreprocessing plan_)
+    (planFeatures plan_)
+    (planPostprocessing plan_ features)
+
+    ;; Assign the global features to all the glyphs
+    (send plan_ assignGlobalFeatures glyphs)
+
+    ;; Assign local features to glyphs
+    (assignFeatures plan_ glyphs))
+
+  (define/public (planPreprocessing plan)
+    (send plan add (mhasheq
+                    'global (append VARIATION_FEATURES (dict-ref DIRECTIONAL_FEATURES (· plan direction)))
+                    'local FRACTIONAL_FEATURES)))
+
+  (define/public (planFeatures plan)
+    ;; Do nothing by default. Let subclasses override this.
+    (void))
+  
+(define/public (planPostprocessing plan userFeatures)
+    (send plan add (append COMMON_FEATURES HORIZONTAL_FEATURES userFeatures)))
+
+  (define/public (assignFeatures plan glyphs)
+    ;; todo: Enable contextual fractions
+    (void)))

pitfall/fontkit/font.rkt

@@ -236,7 +236,7 @@ https://github.com/mbutterick/fontkit/blob/master/src/TTFFont.js
   ((string?) ((option/c (listof symbol?)) (option/c symbol?) (option/c symbol?)) . ->*m . GlyphRun?)
   (unless (· this _layoutEngine)
     (set-field! _layoutEngine this (+LayoutEngine this)))
-  (report* 'in-layout (· this _layoutEngine))
+  (report*/file 'in-layout (· this _layoutEngine))
   (send (· this _layoutEngine) layout string userFeatures script language))
 
 

pitfall/fontkit/glyphinfo.rkt

@@ -0,0 +1,24 @@
+#lang fontkit/racket
+(provide (all-defined-out))
+
+(define-subclass object% (GlyphInfo font-in id-in [codePoints-in empty] [features-in (mhasheq)])
+  (field [_font font-in]
+         [codePoints codePoints-in]
+         [id id-in]
+         [features (mhasheq)])
+
+  (cond
+    [(list? features-in)
+     (for ([feature (in-list features-in)])
+          (hash-set! features feature #t))]
+    [(object? features-in)
+     (hash-set! features (· features-in features))])
+
+  (field [ligatureID #f]
+         [ligatureComponent #f]
+         [ligated #f]
+         [cursiveAttachment #f]
+         [markattachment #f]
+         [shaperInfo #f]
+         [substituted #f]))
+  

pitfall/fontkit/glyphrun.rkt

@@ -6,31 +6,5 @@
 ;; Returned by the font layout method.
 (define-subclass object% (GlyphRun
                           glyphs ; An array of Glyph objects in the run
-                          features-in 
-                          script ; The script that was requested for shaping. This was either passed in or detected automatically.
-                          language) ; The language requested for shaping, as passed in. If `null`, the default language for the script was used.
-
-  
-  ;; An array of GlyphPosition objects for each glyph in the run
-  (field [positions #f])
-  
-  ;; The directionality of the requested script (either ltr or rtl).
-  (field [direction (Script-direction script)])
-  
-  ;; The features requested during shaping. This is a combination of user
-  ;; specified features and features chosen by the shaper.
-  (field [features (cond
-                     [(hash? features-in) features-in]
-                     ;; Convert features to an object
-                     [(list? features-in)
-                      (define f (mhash))
-                      (for ([tag (in-list features)])
-                        (hash-set! f tag #t))
-                      f]
-                     [(not features-in) (mhash)]
-                     [else (error 'glyphrun:unknown-features-type)])])
-
-  
-  
-
-)
+                          positions) ; An array of GlyphPosition objects for each glyph in the run
+                          )

pitfall/fontkit/layout-engine.rkt

@@ -31,53 +31,55 @@ https://github.com/mbutterick/fontkit/blob/master/src/layout/LayoutEngine.js
 
 (define/contract (layout this str-or-glyphs [features #f]
                          ;; Attempt to detect the script if not provided.
-                         [script (report (if (string? str-or-glyphs)
+                         [script (if (string? str-or-glyphs)
                                      (Script-forString str-or-glyphs)
-                                     (Script-forCodePoints (append-map (λ (g) (· g codePoints)) str-or-glyphs))))]
+                                     (Script-forCodePoints (append-map (λ (g) (· g codePoints)) str-or-glyphs)))]
                          [language #f])
   (((or/c string? (listof Glyph?))) ((option/c list?) (option/c symbol?) (option/c symbol?)) . ->*m . GlyphRun?)
   
   (define glyphs
+    ;; Map string to glyphs if needed
     (if (string? str-or-glyphs)
         (send (· this font) glyphsForString str-or-glyphs)
         str-or-glyphs))
 
-  (define glyphRun (make-object GlyphRun glyphs features script language))
+  (report*/file 'starting-layout-in-layout-engine glyphs)
+  (cond
+    [(empty? glyphs) (+GlyphRun glyphs empty)] ; Return early if there are no glyphs
+    [else
+     ;; Setup the advanced layout engine
+     (when (and (· this engine) #;(·? engine setup))
+       (send (· this engine) setup glyphs features script language))
 
-  (if (empty? glyphs)
-      (set-field! positions glyphRun empty)
-      (begin
-        ;; Setup the advanced layout engine ; todo
+     ;; Substitute and position the glyphs
+     (set! glyphs (send this substitute glyphs features script language))
+     (define positions (send this position glyphs features script language))
 
-        ;; Substitute and position the glyphs
-        (send this substitute glyphRun)
-        (send this position glyphRun)
-        (send this hideDefaultIgnorables glyphRun)
-
-        ;; Let the layout engine clean up any state it might have
-        (and (· this engine) (· this engine cleanup))))
-  
-  glyphRun)
+     ;; Let the layout engine clean up any state it might have
+     (when (and (· this engine) #;(·? this engine cleanup))
+       (· this engine cleanup))
+     (+GlyphRun glyphs positions)]))
 
 
-(define/contract (substitute this glyphRun)
-  ((is-a?/c GlyphRun) . ->m . void?)
+(define (substitute this glyphs features script language)
+  #;((is-a?/c GlyphRun) . ->m . void?)
   ;; Call the advanced layout engine to make substitutions
-  (when (and (· this engine) (· this engine substitute))
-    (send (· this engine) substitute glyphRun)))
+  (when (and (· this engine) #;(· this engine substitute))
+    (send (· this engine) substitute glyphs features script language))
+  glyphs)
 
 
-(define/contract (position this glyphRun)
-  ((is-a?/c GlyphRun) . ->m . void?)
+(define (position this glyphs features script language)
+  ((listof Glyph?) (option/c list?) (option/c symbol?) (option/c symbol?) . ->m . (listof GlyphPosition?))
 
-  (define positions (for/list ([g (in-list (· glyphRun glyphs))])
-                      (make-object GlyphPosition (· g advanceWidth))))
-  (set-field! positions glyphRun positions)
   
+  (define positions (for/list ([glyph (in-list glyphs)])
+                              (make-object GlyphPosition (· glyph advanceWidth))))
+  #|
   ;; Call the advanced layout engine. Returns the features applied.
   (define positioned
-    (and (· this engine) (· this engine position)
-         (send (· this engine) position glyphRun)))
+    (and (· this engine) #;(· this engine position)
+         (send (· this engine) position glyphs positions features script language)))
 
   ;; if there is no GPOS table, use unicode properties to position marks.
   ;; todo: implement unicodelayoutengine
@@ -85,7 +87,8 @@ https://github.com/mbutterick/fontkit/blob/master/src/layout/LayoutEngine.js
 
   ;; if kerning is not supported by GPOS, do kerning with the TrueType/AAT kern table
   ;; todo: implement kerning
-  (void)
+|#
+  positions
   )
 
 
@@ -94,15 +97,15 @@ https://github.com/mbutterick/fontkit/blob/master/src/layout/LayoutEngine.js
   (define space (send (· this font) glyphForCodePoint #x20))
   (define-values (new-glyphs new-positions)
     (for/lists (ngs nps)
-      ([glyph (in-list (· glyphRun glyphs))]
-       [pos (in-list (· glyphRun positions))])
-      (cond
-        [(send this isDefaultIgnorable (car (· glyph codePoints)))
-         (define new-pos pos)
-         (set-field! xAdvance new-pos 0)
-         (set-field! yAdvance new-pos 0)
-         (values space new-pos)]
-        [else (values glyph pos)])))
+               ([glyph (in-list (· glyphRun glyphs))]
+                [pos (in-list (· glyphRun positions))])
+               (cond
+                 [(send this isDefaultIgnorable (car (· glyph codePoints)))
+                  (define new-pos pos)
+                  (set-field! xAdvance new-pos 0)
+                  (set-field! yAdvance new-pos 0)
+                  (values space new-pos)]
+                 [else (values glyph pos)])))
   (set-field! glyphs glyphRun new-glyphs)
   (set-field! positions glyphRun new-positions))
 

pitfall/fontkit/ot-layout-engine.rkt

@@ -1,5 +1,5 @@
 #lang fontkit/racket
-(require "gsub-processor.rkt" "gpos-processor.rkt")
+(require "gsub-processor.rkt" "gpos-processor.rkt" "glyphinfo.rkt" (prefix-in Shapers- "shapers.rkt") "shaping-plan.rkt")
 (provide (all-defined-out))
 
 #|
@@ -8,6 +8,7 @@ https://github.com/mbutterick/fontkit/blob/master/src/opentype/OTLayoutEngine.js
 
 (define-subclass object% (OTLayoutEngine font)
   (field [glyphInfos #f]
+         [shaper #f]
          [plan #f]
          [GSUBProcessor #f]
          [GPOSProcessor #f])
@@ -18,10 +19,18 @@ https://github.com/mbutterick/fontkit/blob/master/src/opentype/OTLayoutEngine.js
       (set-field! GSUBProcessor this (+GSUBProcessor font (· font GSUB))))
 
   
-  (report* 'starting-gpos-dingdong)
+  (report* 'dingdong!-starting-gpos)
   (when (· font has-gpos-table?)
       (set-field! GPOSProcessor this (+GPOSProcessor font (· font GPOS))))
 
 
+  (define/public (setup glyphs features script language)
+    ;; Map glyphs to GlyphInfo objects so data can be passed between
+    ;; GSUB and GPOS without mutating the real (shared) Glyph objects.
+    (set! glyphInfos (map (λ (glyph) (+GlyphInfo (· this font) (· glyph id) (· glyph codePoints))) glyphs))
 
-  )
+    ;; Choose a shaper based on the script, and setup a shaping plan.
+    ;; This determines which features to apply to which glyphs.
+    (set! shaper (Shapers-choose script))
+    #;(set! plan (+ShapingPlan (· this font) script language))
+    (send (· this shaper) plan (· this plan) (· this glyphInfos) features)))

pitfall/fontkit/shapers.rkt

@@ -0,0 +1,68 @@
+#lang fontkit/racket
+(require "default-shaper.rkt")
+(provide (all-defined-out))
+
+;; todo: alternative shapers
+(define SHAPERS
+  (hasheq
+;   'arab ArabicShaper ;; Arabic
+;          'mong ArabicShaper ;; Mongolian
+;          'syrc ArabicShaper ;; Syriac
+;          '|nko | ArabicShaper ;; N'Ko
+;          'phag ArabicShaper ;; Phags Pa
+;          'mand ArabicShaper ;; Mandaic
+;          'mani ArabicShaper ;; Manichaean
+;          'phlp ArabicShaper ;; Psalter Pahlavi
+;
+;          'hang HangulShaper ;; Hangul
+;
+;          'bali UniversalShaper ;; Balinese
+;          'batk UniversalShaper ;; Batak
+;          'brah UniversalShaper ;; Brahmi
+;          'bugi UniversalShaper ;; Buginese
+;          'buhd UniversalShaper ;; Buhid
+;          'cakm UniversalShaper ;; Chakma
+;          'cham UniversalShaper ;; Cham
+;          'dupl UniversalShaper ;; Duployan
+;          'egyp UniversalShaper ;; Egyptian Hieroglyphs
+;          'gran UniversalShaper ;; Grantha
+;          'hano UniversalShaper ;; Hanunoo
+;          'java UniversalShaper ;; Javanese
+;          'kthi UniversalShaper ;; Kaithi
+;          'kali UniversalShaper ;; Kayah Li
+;          'khar UniversalShaper ;; Kharoshthi
+;          'khoj UniversalShaper ;; Khojki
+;          'sind UniversalShaper ;; Khudawadi
+;          'lepc UniversalShaper ;; Lepcha
+;          'limb UniversalShaper ;; Limbu
+;          'mahj UniversalShaper ;; Mahajani
+;          ';; mand UniversalShaper ;; Mandaic
+;          ';; mani UniversalShaper ;; Manichaean
+;          'mtei UniversalShaper ;; Meitei Mayek
+;          'modi UniversalShaper ;; Modi
+;          ';; mong UniversalShaper ;; Mongolian
+;          ';; 'nko ' UniversalShaper ;; N’Ko
+;          'hmng UniversalShaper ;; Pahawh Hmong
+;          ';; phag UniversalShaper ;; Phags-pa
+;          ';; phlp UniversalShaper ;; Psalter Pahlavi
+;          'rjng UniversalShaper ;; Rejang
+;          'saur UniversalShaper ;; Saurashtra
+;          'shrd UniversalShaper ;; Sharada
+;          'sidd UniversalShaper ;; Siddham
+;          'sinh UniversalShaper ;; Sinhala
+;          'sund UniversalShaper ;; Sundanese
+;          'sylo UniversalShaper ;; Syloti Nagri
+;          'tglg UniversalShaper ;; Tagalog
+;          'tagb UniversalShaper ;; Tagbanwa
+;          'tale UniversalShaper ;; Tai Le
+;          'lana UniversalShaper ;; Tai Tham
+;          'tavt UniversalShaper ;; Tai Viet
+;          'takr UniversalShaper ;; Takri
+;          'tibt UniversalShaper ;; Tibetan
+;          'tfng UniversalShaper ;; Tifinagh
+;          'tirh UniversalShaper ;; Tirhuta
+          'latn DefaultShaper ;; Latin
+          'DFLT DefaultShaper)) ;; Default
+
+(define (choose script)
+  (dict-ref SHAPERS script DefaultShaper))

pitfall/fontkit/shaping-plan.rkt

@@ -0,0 +1,9 @@
+#lang fontkit/racket
+(provide (all-defined-out))
+
+; * ShapingPlans are used by the OpenType shapers to store which
+; * features should by applied, and in what order to apply them.
+; * The features are applied in groups called stages. A feature
+; * can be applied globally to all glyphs, or locally to only
+; * specific glyphs.
+

pitfall/pdfkit/node_modules/fontkit/index.js

@@ -12417,6 +12417,9 @@ var TTFFont = (_class = function () {
    * @return {GlyphRun}
    */
   TTFFont.prototype.layout = function layout(string, userFeatures, script, language) {
+    console.log("userFeatures="+userFeatures);
+    console.log("script="+script);
+    console.log("language="+language);
     return this._layoutEngine.layout(string, userFeatures, script, language);
   };
 

pitfall/pdfkit/node_modules/restructure/src/Pointer.js

@@ -37,7 +37,7 @@
         return null;
       }
       relative = (function() {
-        console.log("pointer-scope="+this.options.type)
+        //console.log("pointer-scope="+this.options.type)
         switch (this.options.type) {
           case 'local':
             return ctx._startOffset;
@@ -56,13 +56,13 @@
       if (this.options.relativeTo) {
         relative += this.relativeToGetter(ctx);
       }
-      console.log("this._startOffset= "+this._startOffset);
-      console.log("ctx= "+ctx);
-      console.log("ctx._startOffset= "+ctx._startOffset);
-      console.log("offset= "+ offset)
-      console.log("relative= "+ relative)
+      //console.log("this._startOffset= "+this._startOffset);
+      //console.log("ctx= "+ctx);
+      //console.log("ctx._startOffset= "+ctx._startOffset);
+      //console.log("offset= "+ offset)
+      //console.log("relative= "+ relative)
       ptr = offset + relative;
-      console.log("ptr="+ptr+" size="+this.offsetType.size());
+      //console.log("ptr="+ptr+" size="+this.offsetType.size());
       if (this.type != null) {
         val = null;
         decodeValue = (function(_this) {

pitfall/pdfkit/node_modules/restructure/src/Struct.js

@@ -48,7 +48,7 @@
       for (key in fields) {
         type = fields[key];
 
-        console.log("key= " + key );
+        //console.log("key= " + key );
         if (typeof type === 'function') {
           val = type.call(res, res);
         } else {

pitfall/pitfall/alltest.rkt

@@ -14,6 +14,7 @@
            pitfall/test/test11
            pitfall/test/test12 ; ttf subset
            pitfall/test/test13 ; subset with composites
-           pitfall/test/test14 ; Fira ttf with GPOS
+           pitfall/test/test14 ; Fira ttf with GPOS (no kerning)
+           ;pitfall/test/test15 ; Fira ttf with GPOS kerning
            pitfall/page-test
            (submod pitfall/zlib test)))

pitfall/pitfall/embedded.rkt

@@ -43,11 +43,13 @@ https://github.com/mbutterick/pdfkit/blob/master/lib/font/embedded.coffee
 (define/contract (encode this text [features #f])
   ((string?) ((option/c list?)) . ->*m .
              (list/c (listof string?) (listof GlyphPosition?)))
+  (report*/file 'starting-layout-in-embedded (description (· this font)))
   (define glyphRun (send (· this font) layout text features))
   (define glyphs (· glyphRun glyphs))
   (for ([g (in-list glyphs)])
     (· g id))
   (define positions (· glyphRun positions))
+  (report positions)
   (define-values (subset-idxs new-positions)
     (for/lists (idxs posns)
       ([(glyph i) (in-indexed glyphs)]

pitfall/pitfall/racket.rkt

@@ -24,7 +24,8 @@
      sugar/dict
      sugar/stub
      sugar/port
-     sugar/contract)
+     sugar/contract
+     describe)
 
 (module reader syntax/module-reader
   #:language 'pitfall/racket

pitfall/pitfall/test/test15.rkt

@@ -1,5 +1,7 @@
 #lang pitfall/pdftest
 
+;; test kerning from GPOS
+
 (define-runtime-path ttf-path "assets/fira.ttf")
 
 (define (proc doc)
@@ -12,7 +14,7 @@
     [fontSize 25]
     [text "ATAVATA" 100 100 (hash 'width #f)]))
 
-;; test against non-subsetted font version
+
 (define-runtime-path this "test15rkt.pdf")
 (make-doc this #f proc #:test #f)
 

pitfall/pitfall/text.rkt

@@ -2,6 +2,11 @@
 (require sugar/list)
 (provide text-mixin)
 
+#|
+approximates
+https://github.com/mbutterick/pdfkit/blob/master/lib/mixins/text.coffee
+|#
+
 (define (text-mixin [% mixin-tester%])
   (class %
     (super-new)