Custom delayed operations

まず showtree メソッドと .rec_showtree メソッドを読み、次に getArrayElement が DelayedOp のサブクラスをどのように処理するかを追跡します。DelayedAffineSeed と DelayedTranslateSeed を使った例を、temporary Zarr array に対する subset 操作も含めて再現します。完了の条件は、DelayedOp を含む外部クラスが、報告されているメソッド不足エラーなしに、要求された delayed operation の inspection または access flow に参加できることです。

Dear @hpages,

I am working on devising lazy image transformations for https://github.com/HelenaLC/SpatialData/issues/162.

I was wondering if it is possible to use showtree or .rec_showtree methods (or similar methods) for external classes that facilitate delayed operations.

I have tried below, but it requires me to define additional methods for these classes that contain DelayedOp:

setClass(
  "DelayedAffineSeed",
  contains = "DelayedOp",
  slots = c(
    seed = "ANY",
    dim = "integer",
    dimnames = "list",
    m = "matrix",
    axes = "character",
    filter = "character",
    bg.col = "character",
    antialias = "logical",
    trace = "logical"
  )
)

setClass(
  "DelayedTranslateSeed",
  contains = "DelayedOp",
  slots = c(
    seed = "ANY",
    dim = "integer",
    dimnames = "list",
    shift = "numeric",
    axes = "character"
  )
)

# save as zarr
td <- tempfile(fileext = ".zarr")
delayed_img <- writeZarrArray(x = EBImage::imageData(img), zarr_path = td) 

# affine
rotated_delayed_img <- lazy_affine(delayed_img, m = m, filter = "bilinear")

# translate
translate_delayed_img <- lazy_translate(rotated_delayed_img, shift = c(100,200))

# subset
subset_delayed_img <- translate_delayed_img[100:200, 100:200]

> subset_delayed_img@seed
101x101 double: Subset
└─ 1024x512 double: DelayedTranslateSeed object
Error: unable to find an inherited method for function ‘getArrayElement’ for signature ‘x = "DelayedTranslateSeed"’