ITT Rule IDL Version 7.0 User Manual download pdf (Page 188)

188 Chapter 7: Creating an Operation

Example: Data Resample Operation iTool Developer’s Guide

Next, we call the Init method of the superclass. In this case, we are creating a subclass

of the IDLitDataOperation class; this provides us with all of the standard iTool data

operation functionality automatically. We specify three iTool data types on which our

operation will work: “IDLVECTOR”, “IDLARRAY2D”, and “IDLARRAY3D”. Any

“extra” keywords specified in the call to our Init method are passed to the

IDLitDataOperation::Init method via the keyword inheritance mechanism. If the call

to the superclass Init method fails, we return immediately with a value of 0.

Next we store the default values for the three resampling factors (one each for the X,

Y, and Z dimensions) in the object instance data fields

_x, _y, and _z. We register

each of these values as a property of the operation. We also register the METHOD

property, assigning to it an enumerated list with three strings describing three

different interpolation methods (“Nearest Neighbor”, “Linear”, and “Cubic”).

If any “extra” keywords were specified in the call to our Init method, we pass them to

the SetProperty method our example1_opresample object.

Finally, we return the value 1 to indicate successful initialization.

Execute Method

FUNCTION example1_opresample::Execute, data

dims = SIZE(data, /DIMENSIONS)

CASE N_ELEMENTS(dims) OF

1: newdims = dims*ABS([self._x]) > [1]

2: newdims = dims*ABS([self._x, self._y]) > [1, 1]

3: newdims = dims*ABS([self._x, self._y, self._z]) > [1, 1,

ELSE: RETURN, 0

ENDCASE

; No change in size.

IF (ARRAY_EQUAL(newdims, dims)) THEN RETURN, 1

interp = 0 & cubic = 0

CASE (self._method) OF

0: ; do nothing

1: interp = 1

2: cubic = 1

ENDCASE

CASE N_ELEMENTS(dims) OF

1: data = CONGRID(data, newdims[0], $

INTERP = interp, CUBIC = cubic)

2: data = CONGRID(data, newdims[0], newdims[1], $

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ITT Rule IDL Version 7.0 User Manual Page 188