I get the impression that images returned from `dt.collection` carry
the wrong id in their `image.id` field.
On 2016-Jan-07, Tobias Ellinghaus wrote with possible deletions:
> And what version of dt is that?
I have verified this with with 851e3aa and f710269.
> Works for me. Anything else I have to do besides filtering by color
> label?
I realised that this becomes clearer when the list index is printed as
well: Change the script slightly so that
local dt = require "darktable"
local function foo()
print("________________________________________")
print("--- action images ---")
for n, i in pairs(dt.gui.action_images) do
print(n, i.id, i)
end
print("--- collection ---")
for n, i in pairs(dt.collection) do
print(n, i.id, i)
end
end
dt.register_event("shortcut", function(_, _) foo() end, "foo")
You need to narrow down the selection, but not necessarily by color
label. To observe the effect, just have a collection *not containing*
an image with the ID 1. For this example: color-label images with IDs
3, 5, and 7. Collect by that label. Choose ‘Select all’ on the right
pane. Now invoking `foo` prints
________________________________________
--- action images ---
1 3 /tmp/dt/foto/DSC_0259.NEF
2 5 /tmp/dt/foto/DSC_0261.NEF
3 6 /tmp/dt/foto/DSC_0262.NEF
--- collection ---
1 1 /tmp/dt/foto/DSC_0257.NEF
2 2 /tmp/dt/foto/DSC_0258.NEF
3 3 /tmp/dt/foto/DSC_0259.NEF
Observe that the second column should contain the image's database ID,
which is correct for “action images” but wrong for “collection”.
> > By the way: Is there any good reason why `dt.gui.action_images` and
> > `dt.collection` do not return a table that maps the image id to the
> > image?
>
> What would be the benefit over having a list of images?
It would reflect the semantics, and would give Lua the knowledge that
an image ID identifies an image. Returning a list just throws away
this knowledge which then must be recalculated when needed.
My particular usecase: I need to find all images that belong to a
group *and* are in the current collection. To this end, set
intersection on sets of images is req'd. Now to be at least somewhat
efficient, I have to construct potentially huge tables in the Lua
script representing the set of images in the collection.
local collection = {}
for _, img in pairs(dt.collection) do
collection[img.id] = true
end
local targets = {}
for _,m in pairs(someimage:get_group_members()) do
if collection[m.id] then targets[m.id] = m end
end
Stefan
--
http://stefan-klinger.de o/X
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