Optimum fit line breaking and hyphenation

This updates to the newest version of boxes and glue and has some
documentation.

Now implemented the optimum line breaking algorithm from
Donald E. Knuth and Michael F. Plass and the hyphenation algorithm
by Frank Liang.

Rakefile

@@ -22,5 +22,9 @@ task :build  do
 	sh "go build -ldflags \"-X main.version=#{@ets_version}\" -o bin/ets github.com/speedata/ets/ets/ets"
 end
 
-
-
+desc "Create documentation"
+task :doc do
+	Dir.chdir("doc") do
+		sh "asciidoctor ets.adoc -a revnumber=#{@ets_version}"
+	end
+end

Readme.md

@@ -1,4 +1,4 @@
-# ETS Experimental typesetting system
+# ets Experimental typesetting system
 
 This software repository contains a Lua frontend for the typesetting library [“Boxes and Glue”](https://github.com/speedata/boxesandglue) which is an algorithmic typesetting machine in the spirits of TeX.
 
@@ -36,62 +36,64 @@ Contact: Patrick Gundlach <[email protected]>
 ## Sample code
 
 ```lua
--- The document d is the central point for all
-function CreateFontVlist(d)
-    local face, msg = d.loadFace("fonts/CrimsonPro-Regular.ttf")
-    if not face then
-        print(msg)
-        os.exit(-1)
-    end
-    local fnt = d.createFont(face,document.sp("12pt"))
+-- This is still a very vey early preview and will probably not work when
+-- you experiment with the code.
+--
+-- Two functions for fonts and for images just to show how to
+-- create objects and output them.
 
-    local lang_en, msg = d.loadpattern("hyphenationpatterns/hyph-en-us.pat.txt")
-    if not lang_en then
-        print(msg)
-        os.exit(-1)
-    end
+document.info("Reading myfile.lua")
 
-    lang_en.name = "en"
+local ok, face, msg, fnt, lang_en, imgfile, image
 
+function CreateFontVlist(d)
     local lang = node.new("lang")
     lang.lang = lang_en
 
-    local tbl = fnt.shape("the quick brown fox jumps over the lazy dog")
+    local tbl = fnt.shape([[In olden times when wishing still helped one, there lived a king whose daughters
+were all beautiful; and the youngest was so beautiful that the sun itself, which
+has seen so much, was astonished whenever it shone in her face.
+Close by the king's castle lay a great dark forest, and under an old lime-tree in the forest
+was a well, and when the day was very warm, the king's child went out into the
+forest and sat down by the side of the cool fountain; and when she was bored she
+took a golden ball, and threw it up on high and caught it; and this ball was her
+favorite plaything.]])
 
 
     local head, cur = lang, lang
     for _, glyph in ipairs(tbl) do
         if glyph.glyph == 32 then
             local glu = node.new("glue")
             glu.width = fnt.space
+            glu.stretch = fnt.stretch
+            glu.shrink = fnt.shrink
             head = node.insertafter(head,cur,glu)
             cur = glu
         else
             local g = node.new("glyph")
             g.width = glyph.advance
             g.codepoint = glyph.codepoint
+            g.components = glyph.components
             g.font = glyph.font
+            g.hyphenate = glyph.hyphenate
             head = node.insertafter(head,cur,g)
             cur = g
         end
     end
-
-    local hlist = node.hpack(head)
+    d.hyphenate(head)
+    node.append_lineend(cur)
 
     local param = {
-        hsize = document.sp("200pt"),
+        hsize = document.sp("134pt"),
         lineheight = document.sp("12pt"),
     }
 
-    local vl = node.simplelinebreak(hlist,param)
+    local vl = node.linebreak(head,param)
     return vl
 end
 
 local function CreateImageVlist(d)
-    local imgfile = d.loadimagefile("img/ocean.pdf")
-    local image = d.createimage(imgfile)
-
-
+    image = d.createimage(imgfile)
     local imagenode = node.new("image")
     imagenode.img = image
     imagenode.width = document.sp("4cm")
@@ -101,21 +103,38 @@ local function CreateImageVlist(d)
     return vlist
 end
 
-
+-- The document d is the most important item here.
 local d = document.new("out.pdf")
 
+face, msg = d.loadFace("fonts/CrimsonPro-Regular.ttf")
+if not face then
+    print(msg)
+    os.exit(-1)
+end
+
+fnt = d.createFont(face,document.sp("12pt"))
+
+lang_en, msg = d.loadpattern("hyphenationpatterns/hyph-en-us.pat.txt")
+if not lang_en then
+    print(msg)
+    os.exit(-1)
+end
+
+lang_en.name = "en"
+imgfile = d.loadimagefile("img/ocean.pdf")
+
 local fontVL = CreateFontVlist(d)
 local imageVL = CreateImageVlist(d)
-
 d.outputat(document.sp("4cm"),document.sp("27cm"),fontVL)
-d.outputat(document.sp("4cm"),document.sp("26cm"),imageVL)
+d.outputat(document.sp("12cm"),document.sp("27cm"),imageVL)
 d.currentpage().shipout()
 
-
-local ok, msg = d.finish()
+ok, msg = d.finish()
 if not ok then
     print(msg)
     os.exit(-1)
 end
+
+document.info("Reading myfile.lua...done")
 ```
 

core/document.go

@@ -31,6 +31,7 @@ func registerDocumentType(l *lua.LState) {
 	l.SetField(mt, "new", l.NewFunction(newDocument))
 	l.SetField(mt, "sp", l.NewFunction(documentSP))
 	l.SetField(mt, "__index", l.NewFunction(indexDoc))
+	l.SetField(mt, "__newindex", l.NewFunction(newindexDoc))
 }
 
 // Constructor
@@ -87,6 +88,9 @@ func indexDoc(l *lua.LState) int {
 	case "finish":
 		l.Push(l.NewFunction(documentFinish(doc)))
 		return 1
+	case "hyphenate":
+		l.Push(l.NewFunction(documentHyphenate(doc.d)))
+		return 1
 	case "loadimagefile":
 		l.Push(l.NewFunction(documentLoadImageFile(doc.d)))
 		return 1
@@ -99,12 +103,27 @@ func indexDoc(l *lua.LState) int {
 	case "outputat":
 		l.Push(l.NewFunction(documentOutputAt(doc.d)))
 		return 1
+	case "defaultlanguage":
+		ud := newUserDataFromType(l, doc.d.DefaultLanguage)
+		l.Push(ud)
+		return 1
 	default:
 		fmt.Println("default in indexDoc", arg)
 	}
 	return 0
 }
 
+func newindexDoc(l *lua.LState) int {
+	doc := checkDocument(l, 1)
+	switch arg := l.CheckString(2); arg {
+	case "defaultlanguage":
+		ud := checkPatternFile(l, 3)
+		doc.d.SetDefaultLanguage(ud)
+		return 0
+	}
+	return 0
+}
+
 func checkDocument(l *lua.LState, argpos int) *doc {
 	ud := l.CheckUserData(argpos)
 	if v, ok := ud.Value.(*doc); ok {
@@ -128,19 +147,22 @@ func documentFinish(d *doc) lua.LGFunction {
 	}
 }
 
+func documentHyphenate(doc *document.Document) lua.LGFunction {
+	return func(l *lua.LState) int {
+		n := checkNode(l, 1)
+		doc.Hyphenate(n)
+		return 0
+	}
+}
+
 func documentLoadPatternFile(doc *document.Document) lua.LGFunction {
 	return func(l *lua.LState) int {
 		fn := l.CheckString(1)
 		pat, err := doc.LoadPatternFile(fn)
 		if err != nil {
 			return lerr(l, err.Error())
 		}
-		mt := l.NewTypeMetatable(luaLangTypeName)
-		l.SetField(mt, "__index", l.NewFunction(indexLang))
-		l.SetField(mt, "__newindex", l.NewFunction(newIndexLang))
-		ud := l.NewUserData()
-		ud.Value = pat
-		l.SetMetatable(ud, mt)
+		ud := newUserDataFromType(l, pat)
 		l.Push(ud)
 		return 1
 	}
@@ -183,3 +205,18 @@ func newIndexLang(l *lua.LState) int {
 func indexLang(l *lua.LState) int {
 	return 0
 }
+
+func newUserDataFromType(l *lua.LState, n interface{}) *lua.LUserData {
+	var mt *lua.LTable
+	switch t := n.(type) {
+	case *lang.Lang:
+		mt = l.NewTypeMetatable(luaLangTypeName)
+		l.SetField(mt, "__index", l.NewFunction(indexLang))
+		l.SetField(mt, "__newindex", l.NewFunction(newIndexLang))
+		ud := l.NewUserData()
+		ud.Value = t
+		l.SetMetatable(ud, mt)
+		return ud
+	}
+	return nil
+}

core/font.go

@@ -30,11 +30,6 @@ func documentLoadFace(doc *document.Document) lua.LGFunction {
 	}
 }
 
-func getFontFromFace(l *lua.LState) int {
-	stackDump(l)
-	return 1
-}
-
 func checkFace(l *lua.LState, argpos int) *pdf.Face {
 	ud := l.CheckUserData(argpos)
 	if v, ok := ud.Value.(*pdf.Face); ok {
@@ -108,6 +103,12 @@ func indexFont(l *lua.LState) int {
 	case "space":
 		l.Push(lua.LNumber(f.Space))
 		return 1
+	case "stretch":
+		l.Push(lua.LNumber(f.SpaceStretch))
+		return 1
+	case "shrink":
+		l.Push(lua.LNumber(f.SpaceShrink))
+		return 1
 	case "shape":
 		l.Push(l.NewFunction(fontShape(f, fontObj)))
 		return 1