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if not modules then modules = { } end modules ['attr-eff'] = {
version = 1.001,
comment = "companion to attr-eff.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 attributes, nodes = attributes, nodes
local states = attributes.states
local tasks = nodes.tasks
local nodeinjections = backends.nodeinjections
local settexattribute = tex.setattribute
local allocate = utilities.storage.allocate
local setmetatableindex = table.setmetatableindex
attributes.effects = attributes.effects or { }
local effects = attributes.effects
local a_effect = attributes.private('effect')
effects.data = allocate()
effects.values = effects.values or { }
effects.registered = effects.registered or { }
effects.attribute = a_effect
storage.register("attributes/effects/registered", effects.registered, "attributes.effects.registered")
storage.register("attributes/effects/values", effects.values, "attributes.effects.values")
local template = "%s:%s:%s"
local data = effects.data
local registered = effects.registered
local values = effects.values
-- valid effects: normal inner outer both hidden (stretch,rulethickness,effect)
local function effect(...) effect = nodeinjections.effect return effect(...) end
local function extender(effects,key)
if key == "none" then
local d = effect(0,0,0)
effects.none = d
return d
end
end
local function reviver(data,n)
local e = values[n] -- we could nil values[n] now but hardly needed
local d = effect(e[1],e[2],e[3])
data[n] = d
return d
end
setmetatableindex(effects, extender)
setmetatableindex(effects.data, reviver)
effects.handler = nodes.installattributehandler {
name = "effect",
namespace = effects,
initializer = states.initialize,
finalizer = states.finalize,
processor = states.process,
}
local function register(effect,stretch,rulethickness)
local stamp = format(template,effect,stretch,rulethickness)
local n = registered[stamp]
if not n then
n = #values + 1
values[n] = { effect, stretch, rulethickness }
registered[stamp] = n
end
return n
end
local function enable()
tasks.enableaction("shipouts","attributes.effects.handler")
end
effects.register = register
effects.enable = enable
-- interface
local enabled = false
function commands.triggereffect(effect,stretch,rulethickness)
if not enabled then
enable()
enabled = true
end
settexattribute(a_effect,register(effect,stretch,rulethickness))
end
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