[NTG-context] setupexternalfigures and resoĺution

Henning Hraban Ramm texml at fiee.net
Thu Sep 1 10:51:51 CEST 2022


Am 01.09.22 um 10:44 schrieb juh+ntg-context--- via ntg-context:
> 
> Hi,
> 
> what is resolution meant to do?
> 
> Whatever I insert as resolution, I get no change.
> 
> \setupexternalfigure[location={default,local},resolution=30]
> \starttext
> \externalfigure[hacker]
> \stoptext
> 
> What am I missing?

The resolution parameter is still not used by default ConTeXt, sorry.

But you can use it with the attached lua file like:


\loadluafile[grph-downsample]
\doifmodeelse{print}{%
	\def\Resolution{300}
}{%
	\def\Resolution{96}
}%

\setupexternalfigures[
   %directory={./Logos,img},
   conversion=lowres.jpg,
   resolution=\Resolution,
]


Hraban
-------------- next part --------------
if not modules then modules = { } end modules ['grph-downsample'] = {
  version   = 1.100,
  comment   = "companion to grph-inc.mkiv",
  author    = "Peter Münster", -- adapted to LMTX by Hraban
  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

  -- MkIV:
  -- local image = img.scan{filename = oldname}

  -- LMTX:
  local image = figures.getinfo(oldname,1)
  image = image.status.private

  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 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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