luametalatex/luametalatex-pdf-image.lua

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local rawset = rawset
local setdata = node.direct.setdata
local nodenew = node.direct.new
local getwhd = node.direct.getwhd
local setwhd = node.direct.setwhd
local tonode = node.direct.tonode
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local nodewrite = node.write
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-- Mapping extensions to canonical type names if necessary
local imagetype_map = {
-- pdf1 = 'pdf',
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}
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local imagetypes = setmetatable({}, {__index = function(t, k)
local remapped = imagetype_map[k]
local module = remapped and t[remapped] or require('luametalatex-pdf-image-' .. k)
t[k] = module
return module
end})
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local utils = require'luametalatex-pdf-utils'
local strip_floats = utils.strip_floats
local to_bp = utils.to_bp
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local liberal_keys = {height = true, width = true, depth = true, transform = true}
local real_images = {}
local function relaxed_newindex(t, k, v)
if liberal_keys[k] then
return rawset(t, k, v)
else
real_images[t][k] = v
end
end
local function no_newindex(t, k, v)
if liberal_keys[k] then
return rawset(t, k, v)
else
error(string.format("You are not allowed to set %q in an already scanned image"))
end
end
local function get_underlying(t, k)
return assert(real_images[t])[k]
end
local meta = {__index = get_underlying, __newindex = relaxed_newindex}
local restricted_meta = {__index = get_underlying, __newindex = no_newindex}
-- transform isn't documented to be changable but it kind of fits
local function new(spec)
local img, real = {}, {}
real_images[img] = real
if spec then for k,v in next, spec do
(liberal_keys[k] and img or real)[k] = v
end end
img.depth = img.depth or 0
return setmetatable(img, meta)
end
local function scan(img)
local m = getmetatable(img)
local real
if m == restricted_meta then
real = real_images[img]
else
if m ~= meta then img = new(img) end
real = real_images[img]
if real.stream then error[[stream images are not yet supported]] end
assert(real.filename)
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-- TODO: At some point we should just take the lowercased extension
local imagetype = real.filename:match'%.pdf$' and 'pdf'
or real.filename:match'%.png$' and 'png'
or error'Unsupported image format'
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real.filepath = assert(kpse.find_file(real.filename), "Image not found")
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real.imagetype = imagetype
imagetypes[imagetype].scan(real)
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setmetatable(img, restricted_meta)
end
img.transform = img.transform or 0
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-- (Re)Set dimensions
if img.depth and img.height and img.width then
return img
end
local flipped = (img.transform + real.rotation) % 2 == 1
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if not (img.depth or img.height) then img.depth = 0 end
if not img.width and not (img.height and img.depth) then
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local xsize, ysize = real.xsize, real.ysize
if not real.bbox then
local xres, yres = img.xres, img.yres
-- TODO: \pdfvariable Parameters
if xres == 0 then
xres = 72
yres = xres * ((not yres or yres == 0) and 1 or yres)
elseif yres == 0 then
yres = 72
xres = yres * ((not xres or xres == 0) and 1 or xres)
end
local xscale, yscale = 4736286.72/xres, 4736286.72/yres
xsize, ysize = xsize*xscale//1, ysize*yscale//1
end
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local total_y
if flipped then
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img.width = ysize
total_y = xsize
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else
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img.width = xsize
total_y = ysize
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end
if img.height then
img.depth = total_y - img.height
else
img.height = total_y - img.depth
end
else
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local ratio = flipped and xsize / ysize or ysize / xsize
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if img.width then
if img.depth then
img.height = (ratio * img.width - img.depth) // 1
else
img.depth = (ratio * img.width - img.height) // 1
end
else
img.width = ((img.height + img.depth) / ratio) // 1
end
end
return img
end
local img_by_objnum = {}
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-- local function img_from_objnum(objnum, img)
-- img = img or {}
-- real_images[img] = assert(img_by_objnum[objnum])
-- return setmetatable(img, restricted_meta)
-- end
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-- Noop if already reserved
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function reserve(pfile, real)
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local obj = real.objnum or pfile:getobj()
real.objnum = obj
img_by_objnum[obj] = real
return obj
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end
local function write_img(pfile, img)
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local objnum = reserve(pfile, img)
if not img.written then
img.written = true
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imagetypes[img.imagetype].write(pfile, img)
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end
end
local function do_img(data, p, n, x, y)
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local img = assert(img_by_objnum[data >> 3], 'Invalid image ID')
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write_img(p.file, img)
local mirror = data & 4 == 4
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local rotate = (data + img.rotation) & 3
local width, height, depth = getwhd(n)
height = height + depth
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local bbox = img.bbox
local xsize, ysize = img.xsize, img.ysize
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local a, b, c, d, e, f = 1, 0, 0, 1
if bbox then
e, f = -bbox[1], -bbox[2]
else
e, f = 0, 0
xsize, ysize = 65781.76, 65781.76
end
if mirror then
a, e = -a, -e+xsize
end
for i=1,rotate do
a, b, c, d, e, f = -b, a, -d, c, -f+ysize, e
xsize, ysize = ysize, xsize
end
local xscale, yscale = width / xsize, height / ysize
a, c, e = a*xscale, c*xscale, e*xscale
b, d, f = b*yscale, d*yscale, f*yscale
e, f = to_bp(x + e), to_bp(y - depth + f)
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p.resources.XObject['Im' .. tostring(img.objnum)] = img.objnum
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pdf.write('page', strip_floats(string.format('q %f %f %f %f %f %f cm /Im%i Do Q', a, b, c, d, e, f, img.objnum)), nil, nil, p)
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end
local ruleid = node.id'rule'
local ruletypes = node.subtypes'rule'
local imagerule
for n, name in next, ruletypes do
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if name == 'image' then imagerule = n break end
end
assert(imagerule)
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local function node(pfile, img)
img = scan(img)
local n = nodenew(ruleid, imagerule) -- image
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setdata(n, (reserve(pfile, real_images[img]) << 3) | ((img.transform or 0) & 7))
setwhd(n, img.width or -0x40000000, img.height or -0x40000000, img.depth or -0x40000000)
return tonode(n)
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end
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local function write(pfile, img)
img = scan(img)
nodewrite(node(pfile, img))
return img
end
local function immediatewrite(pfile, img)
img = scan(img)
write_img(pfile, real_images[img])
return img
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end
return {
new = new,
scan = scan,
write = write,
node = node,
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from_num = function(i)
local img = {}
real_images[img] = assert(img_by_objnum[i])
return setmetatable(img, restricted_meta)
end,
get_num = function(pfile, img)
return reserve(pfile, real_images[img])
end,
ship = do_img,
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}