ENVI Extensions: Getting notifications from ENVI ROIs
Anonym
A recent project I worked on required an ENVI extension to
respond ROI changes made in the ENVI Layer Manager. Fortunately, ENVI
provides a mechanism that allows an object to do this. First, the object must
be added to the list of observers for each ROI layer. The following command
provides access to these layers:
IDLcf$Get
, /INCLUDE_VIS_CHILDREN,
VIS_LAYERS=oVisLayers
The variable oVisLayers will contain all visible
layers present in the ENVI display. To get only the ROIs, loop through its
contents looking for any instances of IDLcfVisROINative. When one is
encountered the object can be added to the ROI layer’s list of observers using
the following:
void = oVisLayers[i]->
AddObserver
(self)
Now that the object has been added to the list of
observers an OnNotify method must be added. Any notifications from the ROI
layers will be sent to this method.
function
my_class
::OnNotify, oSubject,
strMsg, strArg
The input parameters are:\
- oSubject – A reference to the ENVI object sending the
notification
- strMsg – A string containing the name of the notification (e.g.
SETPROPERTY)
- strArg – A string containing additional notification information
(e.g. HIDE)
Here is a stand-alone example that demonstrates
setting up an object to receive and act on notifications from ROIs in the ENVI
Layer Manager:
;##############################################################################
; This example demonstrates how to get notifications from ENVI
when changes are
; made to ROIs in the Layer Manager.
;##############################################################################
;------------------------------------------------------------------------------
;+
; Event handler used by XMANAGER
;
; :Params:
; sEvent: in, required, type="struct"
; An IDL event structure
;-
pro roi_demo_event, sEvent
widget_control, sEvent.top, GET_UVALUE=oRoiDemo
oRoiDemo->Event, sEvent
end
;------------------------------------------------------------------------------
;+
; Checks ENVI for any ROIs. DIsplays all of the ROIs found in
the message
; text box.
;
; :Keywords:
; PREFIX: in, optional, type="string"
; A string or string array of text to be added to the
beginning of the ROI
; message.
;-
pro roi_demo::CheckROIs, $
PREFIX=prefix
compile_opt idl2, logical_predicate
IDLcf$Get, /INCLUDE_VIS_CHILDREN, VIS_LAYERS=oVisLayers
name = []
for i = 0, n_elements(oVisLayers)-1 do begin
if isa(oVisLayers[i], 'IDLcfVisROINative') then begin
void = oVisLayers[i]->AddObserver(self)
oROI = oVIsLayers[i]->GetParameter('ROI')
if obj_valid(oROI) then begin
name = [name, oROI.name]
endif
endif
endfor
if (n_elements(prefix) EQ 0) then prefix = 'ROIs found:'
str = [prefix,(n_elements(name) GT 0) ? name : 'No ROIs found']
widget_control, widget_info(self.tlb, FIND_BY_UNAME='text_message'), SET_VALUE=str
end
;------------------------------------------------------------------------------
;+
; Creates a dialog for displaying information regarding the ENVI
ROIs
;-
pro roi_demo::Dialog
compile_opt idl2, logical_predicate
e = envi(/CURRENT)
self.tlb = widget_base(/COLUMN, /FLOATING, GROUP_LEADER=e.widget_id,
$
TITLE='ENVI ROI Demo')
xSize = 100
wLabel = widget_label(self.tlb, /ALIGN_LEFT, VALUE='Notification
Information')
wText = widget_text(self.tlb, UNAME='text_params', XSIZE=xSize, YSIZE=3)
wLabel = widget_label(self.tlb, /ALIGN_LEFT, VALUE='ROI Information')
wText = widget_text(self.tlb, UNAME='text_message', XSIZE=50, YSIZE=10)
wBase = widget_base(self.tlb, /ALIGN_RIGHT, /ROW)
wButton = widget_button(wBase, UNAME='check_roi', VALUE='Check ROIs')
widget_control, self.tlb, /REALIZE, SET_UVALUE=self
self->CheckROIs
xmanager, 'roi_demo', self.tlb, /NO_BLOCK
end
;------------------------------------------------------------------------------
;+
; Event handler for the ROI demo's dialog
;
; :Params:
; sEvent: in, required, type="struct"
; An IDL event structure
;-
pro roi_demo::Event, sEvent
compile_opt idl2, logical_predicate
case widget_info(sEvent.id, /UNAME) of
'check_roi': self->CheckROIs
else: print, widget_info(sEvent.id, /UNAME)
endcase
end
;------------------------------------------------------------------------------
;+
; Lifecycle method for initializing the object
;
; :Returns:
; 1 if the object initializes successfully and 0 otherwise
;-
function roi_demo::Init, $
_REF_EXTRA=refExtra
compile_opt idl2, logical_predicate
if (~self->IDLmiObserver::Init(_EXTRA=refextra)) then begin
print, 'Failed to initialize IDLmiObserver'
return, 0
endif
return, 1
end
;------------------------------------------------------------------------------
;+
; This method is for receiving notifications from the notifiers
for which this
; class is an observer.
;
; :Returns:
; 1
;
; :Params:
; oSubject: in, required, type="objref"
; The ENVI object that is sending the notifications
; strMsg: in, required, type="string"
; The notification string (e.g. SETPROPERTY)
; strArg: in, required, type="string"
; A string containing additional notification information
(e.g. HIDE)
;-
function roi_demo::OnNotify, oSubject, strMsg, strArg
compile_opt idl2, logical_predicate
oSubject->GetProperty, NAME=name
help, oSubject, OUTPUT=strHelp
widget_control, widget_info(self.tlb, FIND_BY_UNAME='text_params'), $
SET_VALUE=[strHelp, 'STRMSG: '+strMsg, 'STRARG: '+strArg]
str = ''
case strupcase(strMsg) of
'ADDITEMS': begin
str = ['Adding a new ROI','Press Check ROIs when finished']
end
'REMOVEITEMS': begin
self->CheckROIs, PREFIX=['ROI has been removed','Remaining ROIs:']
return, 1
end
'ROI_DEFINITION_CHANGE': begin
str = name+' has been updated'
end
'SETPROPERTY': begin
case strupcase(strArg) of
'COLOR': begin
oROI = oSubject->GetParameter('ROI')
oROI->GetProperty, COLOR=color
str = name+' color changed to '+strjoin(strtrim(fix(color),2),',')
end
'HIDE': begin
oSubject->GetProperty, HIDE=hide
str = name+' has been '+(hide ? 'hidden' : 'shown')
end
else:
endcase
end
else: print, 'MESSAGE: '+strMsg
endcase
wText = widget_info(self.tlb, FIND_BY_UNAME='text_message')
widget_control, wText, SET_VALUE=str
return, 1
end
;------------------------------------------------------------------------------
;+
; Class structure definition
;
; :Inherits:
; IDLmiObserver
;
; :Fields:
; tlb: This widget ID of the dialog's top level base.
;-
pro roi_demo__define
compile_opt idl2, logical_predicate
void = {roi_demo $
, inherits IDLmiObserver $
, tlb : 0L $
}
end
;------------------------------------------------------------------------------
;+
;-
pro roi_demo
compile_opt idl2, logical_predicate
e = envi(/CURRENT)
if ~isa(e, 'envi') then begin
e = envi()
eView = e->GetView()
file = Filepath('qb_boulder_msi', ROOT_DIR=e.root_dir,
SUBDIRECTORY=['data'])
eRaster = e->OpenRaster(file)
eLayer = eView->CreateLayer(eRaster)
file = Filepath('qb_boulder_roi.xml', ROOT_DIR=e.root_dir,
SUBDIRECTORY=['data'])
eROI = e->OpenROI(file)
nROI = n_elements(eROI)
eLayerROI = objarr(nROI)
for i = 0, nROI-1 do begin
eLayerROI[i] = eLayer->AddROI(eROI[i])
endfor
endif
oROIDemo = obj_new('roi_demo')
oROIDemo->Dialog
end