Re: img.scan in lmtx?

[Henning Hraban Ramm via ntg-context <ntg-context@ntg.nl>]

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> Am 05.08.2021 um 17:51 schrieb Hans Hagen <j.hagen@xs4all.nl>:
> 
> On 8/5/2021 12:26 PM, Henning Hraban Ramm via ntg-context wrote:
>>> Am 08.07.2021 um 23:09 schrieb Hans Hagen <j.hagen@xs4all.nl>:
>>> 
>>> On 7/8/2021 8:31 PM, Henning Hraban Ramm wrote:
>>>>> Am 27.01.2020 um 09:16 schrieb Hans Hagen <j.hagen@xs4all.nl>:
>>>>> 
>>>>> On 1/26/2020 11:50 PM, Henning Hraban Ramm wrote:
>>>>> 
>>>>>> I use the lua function img.scan{filename}, but in lmtx I get "attempt to index a nil value (global 'img')", so I guess this got renamed or moved?
>>>>> Just the high level command:
>>>>> 
>>>>> figures.getinfo(name,page)
>>> 
>>> local t = figures.getinfo("name.pdf",10) -- optional page number
>> Finally coming back to this.
>> Since I don’t know what the function is supposed to return, I thought I’ll check:
>>   local image = figures.getinfo(imgname,1)
>>   print("TEST", image, #image)
>>   for k, v in ipairs(image) do
>>     print("TEST", oldname, k, v)
>>   end
>> but that gives only:
>> TEST    table: 0x7fbd4e4e1320    0
>> i.e. the table is empty.
>> Or did I misunderstand something? My Lua skills are still severely lacking...
> it's a hash not an array so .... pairs

Oops. Ok, that means the information I’m looking for is in image.status.private. Who would have thought. 

Now grph-downsample.lua works with LMTX.

Hraban


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if not modules then modules = { } end modules ['grph-downsample'] = {
  version   = 1.001,
  comment   = "companion to grph-inc.mkiv",
  author    = "Peter Münster",
  copyright = "PRAGMA ADE / ConTeXt Development Team",
  license   = "see context related readme files"
}

assert(not figures.getinfo2)

figures.getinfo2 = function(name, page) -- [ [NTG-context] Pdf info with Lua/Ctx API ]
 if type(name) == "string" then
   name = { name = name, page = page }
 end

 if name.name then
   local data = figures.push(name)
   local info = figures.identify()

   if info.status.status ~= 0 then
     figures.check() -- !Counts pages here!
   end

   figures.pop()

   return --data
          info
 end
end


local format = string.format
-- figures.cachepaths.path = "cache" -- should be setup-option
local function sample_down(oldname, newname, resolution)
  print("DOWNSAMPLE sample_down " .. oldname .. " to " .. newname)
  local request = figures.current().request
  local width = request.width
  local height = request.height
  if resolution == "" then -- or (not width and not height) then
    print(format("DOWNSAMPLE Nothing to do: %s, %s, %s dpi, %s x %s px", oldname, newname, resolution, width, height))
    return
  end
  local TEXpt = 65536
  local inch = 72.27
  -- local image = img.scan{filename = oldname}
  local image = figures.getinfo(oldname,1)
  image = image.status.private
  --[[
  print("DOWNSAMPLE", image, #image)
  for k, v in pairs(image) do
    print(k, v)
  end
  width	170506321.92
  height	255759482.88
  colordepth	8
  colorspace	2
  orientation	1
  depth	0
  filename	img/09115528.jpg
  yres	72
  ysize	3888
  transform	0
  xres	72
  xsize	2592
  rotation	0
  ]]
  -- STOP
  local xy = image.xsize / image.ysize
  if (not width and not height) then
    -- no size requested? use default width
    width = 300 * TEXpt
  end
  if not width then
    height = height / TEXpt
    width = height * xy
  end
  if not height then
    width = width / TEXpt
    height = width / xy
  end
  width = math.floor(width)
  height = math.floor(height)
  print(format("DOWNSAMPLE image size %dx%dpx. requested %dx%d?", image.xsize, image.ysize, width, height))
  local xsize = math.floor(resolution * width / inch)
  local ysize = math.floor(resolution * height / inch)
  print(format("DOWNSAMPLE size %d x %d to %d x %d", image.xsize, image.ysize, xsize, ysize))
  if xsize < image.xsize or ysize < image.ysize then
    local s = format("gm convert -resize %dx%d -resample %dx%d %s %s",
                     xsize, ysize, resolution, resolution, oldname, newname)
    print("DOWNSAMPLE Conversion: " .. s)
    os.execute(s)
  else
    print(format("DOWNSAMPLE Nothing to do: %s, %s, %s dpi, %d x %d px", oldname, newname, resolution, width, height))
    -- print(format("DOWNSAMPLE Nothing to do: %s, %s, %s", oldname, newname, resolution))
    print(format("DOWNSAMPLE xsize = %d, ysize = %d", xsize, ysize))
  end
end

local formats = {"png", "jpg", "gif"}

for _, s in ipairs(formats) do
  figures.converters[s] = figures.converters[s] or {}
  figures.converters[s]["lowres." .. s] = sample_down
end

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