| Current File : //usr/share/texlive/texmf-dist/doc/luatex/base/luatex-harfbuzz.tex |
% language=uk
\environment luatex-style
\startcomponent luatex-harfbuzz
\definelayer
[hbpage]
[width=\paperwidth,
height=\paperheight]
\setupbackgrounds
[page]
[background=hbpage,
state=start]
\startchapter[reference=harfbuzz,title={The HarfBuzz libraries}]
\startsection[title={The \type {luaharfbuzz} library}][library=luaharfbuzz]
At the moment the documentation of the library is a raw "html-to-pdf"
rendering of the \type{index.html} file under \type{luaharfbuzz/docs}
folder of the source code. The example is almost the verbatim copy
of the file under \type{luaharfbuzz/examples}.
\page
\dorecurse{17}{%
\setlayer[hbpage][x=0mm,y=0mm,]{\externalfigure[graphics/luaharfbuzz.pdf][page=\recurselevel]}
\blank
\page[empty]
}
\startsubsection[title={Example}]
The example is (a small modification of) the file \type{core_types.lua}
and it requires the file \type{harfbuzz.lua}; both are
under \type{luaharfbuzz} folder of the source code.
The fonts \type{notonastaliq.ttf} and \type{amiri-regular.ttf'} are under
\type{luaharfbuzz/fonts}.
\blank[3*big]
\startbuffer[hbmod]
local hb = require("luaharfbuzz")
-- special tags
hb.Tag.NONE = hb.Tag.new()
-- special script codes (ISO 15924)
hb.Script.COMMON = hb.Script.new("Zyyy")
hb.Script.INHERITED = hb.Script.new("Zinh")
hb.Script.UNKNOWN = hb.Script.new("Zzzz")
hb.Script.INVALID = hb.Script.from_iso15924_tag(hb.Tag.NONE)
-- directions
hb.Direction.INVALID = hb.Direction.new("invalid")
hb.Direction.LTR = hb.Direction.new("ltr")
hb.Direction.RTL = hb.Direction.new("rtl")
hb.Direction.TTB = hb.Direction.new("ttb")
hb.Direction.BTT = hb.Direction.new("btt")
-- special languages
hb.Language.INVALID = hb.Language.new()
hb.shape = function(font, buf, options)
options = options or { }
-- Apply options to buffer if they are set.
if options.language then buf:set_language(options.language) end
if options.script then buf:set_script(options.script) end
if options.direction then buf:set_direction(options.direction) end
-- Guess segment properties, in case all steps above have failed
-- to set the right properties.
buf:guess_segment_properties()
local features = {}
-- Parse features
if type(options.features) == "string" then
for fs in string.gmatch(options.features, '([^,]+)') do
local feature = hb.Feature.new(fs)
if feature then
table.insert(features, hb.Feature.new(fs))
else
error(string.format("Invalid feature string: '%s'", fs))
end
end
elseif type(options.features) == "table" then
features = options.features
elseif options.features then -- non-nil but not a string or table
error("Invalid features option")
end
return hb.shape_full(font,buf,features,options.shapers or {})
end
-- For backward compatibility
hb.Buffer.HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES = hb.Buffer.CLUSTER_LEVEL_MONOTONE_GRAPHEMES
hb.Buffer.HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS = hb.Buffer.CLUSTER_LEVEL_MONOTONE_CHARACTERS
hb.Buffer.HB_BUFFER_CLUSTER_LEVEL_CHARACTERS = hb.Buffer.CLUSTER_LEVEL_CHARACTERS
hb.Buffer.HB_BUFFER_CLUSTER_LEVEL_DEFAULT = hb.Buffer.CLUSTER_LEVEL_DEFAULT
hb.Tag.HB_TAG_NONE = hb.Tag.NONE
hb.Script.HB_SCRIPT_COMMON = hb.Script.COMMON
hb.Script.HB_SCRIPT_INHERITED = hb.Script.INHERITED
hb.Script.HB_SCRIPT_UNKNOWN = hb.Script.UNKNOWN
hb.Script.HB_SCRIPT_INVALID = hb.Script.INVALID
hb.Language.HB_LANGUAGE_INVALID = hb.Language.INVALID
hb.Direction.HB_DIRECTION_INVALID = hb.Direction.INVALID
hb.Direction.HB_DIRECTION_LTR = hb.Direction.LTR
hb.Direction.HB_DIRECTION_RTL = hb.Direction.RTL
hb.Direction.HB_DIRECTION_TTB = hb.Direction.TTB
hb.Direction.HB_DIRECTION_BTT = hb.Direction.BTT
hb.Direction.HB_DIRECTION_IS_VALID = hb.Direction.is_valid
hb.Direction.HB_DIRECTION_IS_HORIZONTAL = hb.Direction.is_horizontal
hb.Direction.HB_DIRECTION_IS_VERTICAL = hb.Direction.is_vertical
hb.Direction.HB_DIRECTION_IS_FORWARD = hb.Direction.is_forward
hb.Direction.HB_DIRECTION_IS_BACKWARD = hb.Direction.is_backward
hb.Buffer.get_glyph_infos_and_positions = hb.Buffer.get_glyphs
return hb
\stopbuffer
\blank[3*big]
The file \type{harfbuzz.lua}:
\typebuffer[hbmod]
\startbuffer[hbex]
local harfbuzz = require('harfbuzz')
-- Harfbuzz API Version
print("Harfbuzz API version", harfbuzz.version())
-- Shapers available
print("Shapers:", harfbuzz.shapers())
-- harfbuzz.Face
local face = harfbuzz.Face.new('notonastaliq.ttf')
print('\nFace upem = '..face:get_upem())
-- harfbuzz.Font
local font = harfbuzz.Font.new(face)
local xs, xy = font:get_scale()
print("\nDefault font scale = X: "..xs..", Y: "..xy)
-- harfbuzz.Buffer
local text = "یہ" -- U+06CC U+06C1
local buf = harfbuzz.Buffer.new()
buf:add_utf8(text)
-- harfbuzz.shape (Shapes text)
print("\nShaping '"..text.."' set with Noto Nastaliq Urdu")
harfbuzz.shape(font, buf, { language = harfbuzz.Language.new("urd"),
script = harfbuzz.Script.new("Arab"), direction = harfbuzz.Direction.RTL})
local glyphs = buf:get_glyphs()
print("No. of glyphs", #glyphs)
for k,v in pairs(glyphs) do
print(k)
for k1,v1 in pairs(v) do
print("",k1,v1)
end
end
local opts = { language = harfbuzz.Language.new("eng"),
script = harfbuzz.Script.new("Latn"), direction = harfbuzz.Direction.LTR }
local amiri_face = harfbuzz.Face.new('amiri-regular.ttf')
local amiri_font = harfbuzz.Font.new(amiri_face)
-- shaping '123' w/o features
print("\nShaping '123' set with Amiri Regular and no features")
buf= harfbuzz.Buffer.new()
buf:add_utf8("123")
harfbuzz.shape(amiri_font, buf, opts)
glyphs = buf:get_glyphs()
for k,v in pairs(glyphs) do
print(k)
for k1,v1 in pairs(v) do
print("",k1,v1)
end
end
-- shaping '123' with '+numr' (numerators)
print("\nShaping '123' set with Amiri Regular with 'numr' feature turned on")
buf= harfbuzz.Buffer.new()
buf:add_utf8("123")
opts.features = "+numr"
harfbuzz.shape(amiri_font, buf, opts)
glyphs = buf:get_glyphs()
for k,v in pairs(glyphs) do
print(k)
for k1,v1 in pairs(v) do
print("",k1,v1)
end
end
\stopbuffer
The example:
\typebuffer[hbex]
\startbuffer[hbout]
Harfbuzz API version 2.6.4
Shapers: graphite2 ot fallback
Face upem = 2048
Default font scale = X: 2048, Y: 2048
Shaping 'یہ' set with Noto Nastaliq Urdu
No. of glyphs 4
1
flags 1.0
cluster 2
codepoint 277
x_advance 472.0
y_advance 0.0
x_offset 0.0
y_offset 0.0
2
cluster 0
codepoint 19
x_advance 0.0
y_advance 0.0
x_offset 310.0
y_offset -383.0
3
cluster 0
codepoint 985
x_advance 0.0
y_advance 0.0
x_offset 0.0
y_offset 0.0
4
cluster 0
codepoint 316
x_advance 731.0
y_advance 0.0
x_offset 0.0
y_offset -68.0
Shaping '123' set with Amiri Regular and no features
1
cluster 0
codepoint 20
x_advance 1090.0
y_advance 0.0
x_offset 0.0
y_offset 0.0
2
cluster 1
codepoint 21
x_advance 1090.0
y_advance 0.0
x_offset 0.0
y_offset 0.0
3
cluster 2
codepoint 22
x_advance 1090.0
y_advance 0.0
x_offset 0.0
y_offset 0.0
Shaping '123' set with Amiri Regular with 'numr' feature turned on
1
cluster 0
codepoint 6673
x_advance 600.0
y_advance 0.0
x_offset 0.0
y_offset 0.0
2
cluster 1
codepoint 6674
x_advance 600.0
y_advance 0.0
x_offset 0.0
y_offset 0.0
3
cluster 2
codepoint 6675
x_advance 600.0
y_advance 0.0
x_offset 0.0
y_offset 0.0
\stopbuffer
\blank[3*big]
The result:
\typebuffer[hbout]
\stopsubsection
\stopsection
\stopchapter
\stopcomponent