beta 2011.05.09 16:28

1 files changed, 151 insertions, 0 deletions

diff --git a/tex/context/base/scrp-eth.lua b/tex/context/base/scrp-eth.lua
new file mode 100644
index 000000000..75fad2481
--- /dev/null
+++ b/tex/context/base/scrp-eth.lua
@@ -0,0 +1,151 @@
+if not modules then modules = { } end modules ['scrp-eth'] = {
+    version   = 1.001,
+    comment   = "companion to scrp-ini.mkiv",
+    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
+    copyright = "PRAGMA ADE / ConTeXt Development Team",
+    license   = "see context related readme files"
+}
+
+-- at some point I will review the script code but for the moment we
+-- do it this way; so space settings like with cjk yet
+
+local has_attribute      = node.has_attribute
+local insert_node_before = node.insert_before
+
+local nodepool           = nodes.pool
+
+local new_glue           = nodepool.glue
+local new_penalty        = nodepool.penalty
+
+local nodecodes          = nodes.nodecodes
+local glyph_code         = nodecodes.glyph
+
+local a_prestat          = attributes.private('prestat')
+local a_preproc          = attributes.private('preproc')
+
+local categorytonumber   = scripts.categorytonumber
+local numbertocategory   = scripts.numbertocategory
+local hash               = scripts.hash
+local numbertodataset    = scripts.numbertodataset
+
+local fonthashes         = fonts.hashes
+local parameters         = fonthashes.parameters
+
+local space, stretch, shrink, lastfont
+
+local inter_character_space_factor   = 1
+local inter_character_stretch_factor = 1
+local inter_character_shrink_factor  = 1
+
+local function space_glue(current)
+    local data = numbertodataset[has_attribute(current,a_preproc)]
+    if data then
+        inter_character_space_factor   = data.inter_character_space_factor   or 1
+        inter_character_stretch_factor = data.inter_character_stretch_factor or 1
+        inter_character_shrink_factor  = data.inter_character_shrink_factor  or 1
+    end
+    local font = current.font
+    if lastfont ~= font then
+        local pf = parameters[font]
+        space    = pf.space
+        stretch  = pf.space_stretch
+        shrink   = pf.space_shrink
+        lastfont = font
+    end
+    return new_glue(
+        inter_character_space_factor   * space,
+        inter_character_stretch_factor * stretch,
+        inter_character_shrink_factor  * shrink
+    )
+end
+
+local function insert_space(head,current)
+    insert_node_before(head,current,space_glue(current))
+end
+
+local function insert_zerowidthspace(head,current)
+    insert_node_before(head,current,new_glue(0))
+end
+
+local function insert_nobreakspace(head,current)
+    insert_node_before(head,current,new_penalty(10000))
+    insert_node_before(head,current,space_glue(current))
+end
+
+-- syllable [zerowidthspace] syllable
+-- syllable [zerowidthspace] word
+-- syllable [zerowidthspace] sentence
+-- word     [nobreakspace]   syllable
+-- word     [space]          word
+-- word     [space]          sentence
+-- sentence [nobreakspace]   syllable
+-- sentence [space]          word
+-- sentence [space]          sentence
+
+local injectors = { -- [previous] [current]
+    ethiopic_syllable = {
+        ethiopic_syllable = insert_zerowidthspace,
+        ethiopic_word     = insert_nobreakspace,
+        ethiopic_sentence = insert_nobreakspace,
+    },
+    ethiopic_word = {
+        ethiopic_syllable = insert_space,
+        ethiopic_word     = insert_space,
+        ethiopic_sentence = insert_space,
+    },
+    ethiopic_sentence = {
+        ethiopic_syllable = insert_space,
+        ethiopic_word     = insert_space,
+        ethiopic_sentence = insert_space,
+    },
+}
+
+local function process(head,first,last)
+    if first ~= last then
+        local injector = false
+        local current = first
+        while current do
+            local id = current.id
+            if id == glyph_code then
+                local prestat = has_attribute(current,a_prestat)
+                local category = numbertocategory[prestat]
+                if injector then
+                    local action = injector[category]
+                    if action then
+                        action(head,current)
+                    end
+                end
+                injector = injectors[category]
+            else
+                -- nothing yet
+            end
+            if current == last then
+                break
+            else
+                current = current.next
+            end
+        end
+    end
+end
+
+scripts.installmethod {
+    name     = "ethiopic",
+    process  = process,
+    datasets = {
+        default = {
+            inter_character_space_factor   = 1,
+            inter_character_stretch_factor = 1,
+            inter_character_shrink_factor  = 1,
+        },
+        half = {
+            inter_character_space_factor   = 0.5,
+            inter_character_stretch_factor = 0.5,
+            inter_character_shrink_factor  = 0.5,
+        },
+        quarter = {
+            inter_character_space_factor   = 0.25,
+            inter_character_stretch_factor = 0.25,
+            inter_character_shrink_factor  = 0.25,
+        },
+    },
+}