Ipelib

Programming in Lua

The library libipelua implements Lua bindings for many classes in Ipelib. The bindings are available in Lua ipelets, as well as in Lua scripts executed using the ipescript program.

These pages document the Lua bindings to Ipelib:

When writing Ipelets in Lua, you have access to additional methods provided by the Ipe program itself:

Examples

Here is a Lua script that reads an Ipe document and then recenters each page on the paper. You can run this script as "ipescript recenter".

-- recenter.lua
-- center objects on each page of the document

if #argv ~= 2 then
  io.stderr:write("Usage: ipescript recenter <inputfile> <outputfile>\n")
  return
end

inname = argv[1]
outname = argv[2]

doc = assert(ipe.Document(inname))

-- make sure we have size information for text
assert(doc:runLatex())

layout = doc:sheets():find("layout")
fs = layout.framesize

for i,p in doc:pages() do
  box = ipe.Rect()
  for j = 1,#p do
    box:add(p:bbox(j))
  end
  nx = (fs.x - box:width()) / 2
  ny = (fs.y - box:height()) / 2
  trans = ipe.Vector(nx, ny) - box:bottomLeft()
  m = ipe.Translation(trans)
  for j = 1,#p do
    p:transform(j, m)
  end
end
doc:save(outname)

Here is a small Lua script that takes an Ipe document and exports each view separately in EPS format:

-- splitviews.lua
-- export each view of an Ipe document separately

if #argv ~= 1 then
  io.stderr:write("Usage: ipescript splitviews <file>\n")
  return
end
fname = argv[1]

i = fname:find("%.[^.]+$")
if i then
  epsname = fname:sub(1,i-1)
else
  epsname = fname
end

doc = assert(ipe.Document(fname))

-- need latex information to save as Postscript
assert(doc:runLatex())

for i,p in doc:pages() do
  io.stderr:write("Saving page " .. i .. "\n") 
  for j = 1, p:countViews() do
    out = epsname .. "-" .. i .. "-" .. j .. ".eps"
    io.stderr:write("Saving view " .. i .. "-" .. j .. " as " .. out .. "\n") 
    doc:exportView(out, "eps", nil, i, j)
  end
end

For more examples, have a look at the scripts in your Ipe installation, such as add-style.lua or update-styles.lua.