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if not modules then modules = { } end modules ['lpdf-grp'] = {
version = 1.001,
comment = "companion to lpdf-ini.mkiv",
author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
copyright = "PRAGMA ADE / ConTeXt Development Team",
license = "see context related readme files"
}
local format = string.format
local backends, lpdf = backends, lpdf
local nodeinjections = backends.pdf.nodeinjections
local colors = attributes.colors
local basepoints = number.dimenfactors["bp"]
local inches = number.dimenfactors["in"]
local nodeinjections = backends.pdf.nodeinjections
local codeinjections = backends.pdf.codeinjections
local registrations = backends.pdf.registrations
local pdfdictionary = lpdf.dictionary
local pdfarray = lpdf.array
local pdfconstant = lpdf.constant
local pdfboolean = lpdf.boolean
local pdfreference = lpdf.reference
local pdfflushobject = lpdf.flushobject
-- can also be done indirectly:
--
-- 12 : << /AntiAlias false /ColorSpace 8 0 R /Coords [ 0.0 0.0 1.0 0.0 ] /Domain [ 0.0 1.0 ] /Extend [ true true ] /Function 22 0 R /ShadingType 2 >>
-- 22 : << /Bounds [ ] /Domain [ 0.0 1.0 ] /Encode [ 0.0 1.0 ] /FunctionType 3 /Functions [ 31 0 R ] >>
-- 31 : << /C0 [ 1.0 0.0 ] /C1 [ 0.0 1.0 ] /Domain [ 0.0 1.0 ] /FunctionType 2 /N 1.0 >>
local function shade(stype,name,domain,color_a,color_b,n,colorspace,coordinates,separation)
local f = pdfdictionary {
FunctionType = 2,
Domain = pdfarray(domain), -- domain is actually a string
C0 = pdfarray(color_a),
C1 = pdfarray(color_b),
N = tonumber(n),
}
separation = separation and registrations.getspotcolorreference(separation)
local s = pdfdictionary {
ShadingType = stype,
ColorSpace = separation and pdfreference(separation) or pdfconstant(colorspace),
Function = pdfreference(pdfflushobject(f)),
Coords = pdfarray(coordinates),
Extend = pdfarray { true, true },
AntiAlias = pdfboolean(true),
}
lpdf.adddocumentshade(name,pdfreference(pdfflushobject(s)))
end
function lpdf.circularshade(name,domain,color_a,color_b,n,colorspace,coordinates,separation)
shade(3,name,domain,color_a,color_b,n,colorspace,coordinates,separation)
end
function lpdf.linearshade(name,domain,color_a,color_b,n,colorspace,coordinates,separation)
shade(2,name,domain,color_a,color_b,n,colorspace,coordinates,separation)
end
function lpdf.colorspec(model,ca,default)
if ca and ca > 0 then
local cv = colors.value(ca)
if cv then
if model == 1 then
model = cv[1]
end
if model == 2 then
return pdfarray { cv[2] }
elseif model == 3 then
return pdfarray { cv[3],cv[4],cv[5] }
elseif model == 4 then
return pdfarray { cv[6],cv[7],cv[8],cv[9] }
elseif model == 5 then
return pdfarray { cv[13] }
end
end
end
if default then
return default
end
end
-- inline bitmaps but xform'd
--
-- we could derive the colorspace if we strip the data
-- and divide by x*y
local template = "q BI %s ID %s > EI Q"
local factor = 72/300
function nodeinjections.injectbitmap(t)
-- encoding is ascii hex, no checking here
local xresolution, yresolution = t.xresolution or 0, t.yresolution or 0
if xresolution == 0 or yresolution == 0 then
return -- fatal error
end
local colorspace = t.colorspace
if colorspace ~= "rgb" and colorspace ~= "cmyk" and colorspace ~= "gray" then
-- not that efficient but ok
local d = string.gsub(t.data,"[^0-9a-f]","")
local b = math.round(#d / (xresolution * yresolution))
if b == 2 then
colorspace = "gray"
elseif b == 6 then
colorspace = "rgb"
elseif b == 8 then
colorspace = "cmyk"
end
end
if colorspace == "gray" then
colorspace = pdfconstant("DeviceGray")
elseif colorspace == "rgb" then
colorspace = pdfconstant("DeviceRGB")
elseif colorspace == "cmyk" then
colorspace = pdfconstant("DeviceCMYK")
else
return -- fatal error
end
local d = pdfdictionary {
W = xresolution,
H = yresolution,
CS = colorspace,
BPC = 8,
F = pdfconstant("AHx"),
}
-- for some reasons it only works well if we take a 1bp boundingbox
local urx, ury = 1/basepoints, 1/basepoints
-- urx = (xresolution/300)/basepoints
-- ury = (yresolution/300)/basepoints
local width, height = t.width or 0, t.height or 0
if width == 0 and height == 0 then
width = factor * xresolution / basepoints
height = factor * yresolution / basepoints
elseif width == 0 then
width = height * xresolution / yresolution
elseif height == 0 then
height = width * yresolution / xresolution
end
local image = img.new {
stream = format(template,d(),t.data),
width = width,
height = height,
bbox = { 0, 0, urx, ury },
}
return img.node(image)
end
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