Am 02.09.22 um 10:39 schrieb Keith McKay via ntg-context:
Thanks for this code Hraban. I tried this last night and it worked
really well. I did have one stumbling block when I noticed that those
image files with a space in their names were not found, however
renaming without a space solved the problem. Is this a bug or a feature?
The call to gm convert was lacking quoting of the file names. Fixed in
attachment.
While the code does some downsampling, the calculation is not always
right, because it doesn’t consider scaling (or something like that).
Hraban
if not modules then modules = { } end modules ['grph-downsample'] = {
version = 1.101,
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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