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Getting creative with ENVI + IDL

Zachary Norman

When it comes to ENVI + IDL, I like to get creative and see what else I can really accomplish with all of the awesome tools I have available. To give you some background on this blog, a few months ago I got my first DSLR camera. When I wanted to take pictures of larger scenes I realized that I didn't have the tools I needed to generate mosaics or panoramas of vast landscapes.

From a previous blog post, Creating Mosaics from Pluto Imagery, I had a very simple approach to reference images with respect to one another which was just setting a constant offset between each image. If you are taking pictures by hand, this is a little more difficult to do, so I turned to my great friend IDL for some help.

With IDL's function graphics you can create interactive graphics windows. In order to correctly position my images, this is what I decided to use because I can interactively move around different images and put them where they should be. Then, based on their final positions in the window, I can create spatial references for ENVI to have an idea where the images are relative to one another. This is important because if you want to use ENVI's Seamless Mosaic tool or Image Registration Workflow then you need to have spatial references for your images.

Here is a screenshot of what the interface looks like for the widget I created with some sample images:

In order to use the tool you will need to download the code (see below). Once you get the code and run the procedure, then a dialog will appear asking you to select some images you want to load. The allowed formats are any images that can be read by IDL's READ_IMAGE function. After you select your images, the widget interface above will appear with different actions you can perform on a selected image (the images selected when there is a blue box around it). To load an image into the display, you just need to double click on the name of the file in the top right corner of the image. If you get any of the images in a goofy position, orientation, or weird zoom, then just select the image and press the 'Reset Properties' button.

Once you are done, press the 'Done!' button. This will create ENVI formatted files for every image in the display. Once this has finished, then a prompt will appear asking if you want to open up the images in ENVI. If you select yes, then you will see something like the following after the images are loaded:

At this point, you might need to use the Image Registration Workflow to really get the images lined up better before using the Seamless Mosaic tool. Have fun mosaicing!

Here is the code for the widget that I call IDLMosaic. Feel free to edit/modify the code in any way you want. Copy and past the code into IDL and save it as "idlmosaic.pro"

;+

;  

;   Program designed to create an interactive environment for lining up images

;   relative to one another so that they can be georeferenced in ENVI. When you

;   press the run button in IDL, a dialog will pop up that prompts you to select

;   images that will be read into IDL. The supported file formats are the same

;   for the READ_IMAGE function in IDL.

;

; :Author: Zachary Norman

;-

function ImageInfo::init, oWin, MAX_WIDTH = max_width

  compile_opt idl2

  self.ImageHash = orderedhash()

  self.oImages = list()

  self.oFiles = list()

  ;check if a max width was supplied

  if (max_width eq !NULL) then begin

    self.max_width = .33d

  endif else begin

    self.max_width = double(max_width)

  endelse

  ;check if a window reference was supplied, if not make one

  if ~isa(oWin, 'GRAPHICSWIN')then begin

    self.oWin = window()

  endif else begin

    self.oWin = oWin

  endelse

  return, 1

end

pro ImageInfo::AddImage, drawfile, CURRENT = current

  compile_opt idl2

  ;overall hash with the image info

  info_hash = self.ImageHash

  oImages = self.oImages

  oFiles = self.oFiles

  max_width = self.max_width

  ;only draw the image if we have not yet

  if ~info_hash.haskey(strlowcase(drawfile)) then begin

    ;save the drawfile

    oFiles.add,drawfile

    ;new hash to add for file

    file_hash = orderedhash()

    ;only check if we have drawn something to the screen

    if (n_elements(oDrawnAlready) gt 0) then begin

      idx = (where(drawfile eq oDrawnAlready.ToArray()))[0]

      if (idx ne -1) then begin

        print,'Image drawn already, returning...'

        return

      endif

    endif

    ;read the image data

    dat = read_image(drawfile)

    dims = size(dat, /DIMENSIONS)

    ;remember the iamge diensions

    file_hash['DIMS'] = dims

    ;assume the number of channels is the smallest dimension

    ;if we have more than one, then we need to account for interleave change to BSQ

    if (n_elements(dims) eq 2) then begin

      nchannels = 1

      ;calculate aspect ratio

      aspect = float(dims[1])/dims[0]

     

      ;resize data so we use less memory

      dat = congrid(dat, dims[0]/4, dims[1]/4, /INTERP)

    endif else begin

      nchannels = min(dims)

      channel = (where(dims eq nchannels))[0]

      ;change image interleave to BSQ

      case channel of

        0:dat = transpose(dat, [1,2,0])

        1:dat = transpose(dat, [0,2,1])

        2:;do nothing

      endcase

     

      dims = size(dat, /DIMENSIONS)

      ;calculate aspect ratio

      aspect = float(dims[1])/dims[0]

      ;resize data to consume less memory

      dat = congrid(dat, dims[0]/4, dims[1]/4, nchannels, /INTERP)

    endelse

 

    ;add a random offset to the image so they don't all line up

    ;on top of one another

    center = [.5, .5] + randomu(!NULL)/10

    ;determine the image position

    if (aspect gt 1) then begin

      xrange = center[0] + (max_width/aspect)*[-.5, .5]

      yrange = center[1] + max_width*[-.5, .5]

    endif else begin

      xrange = center[0] + max_width*[-.5, .5]

      yrange = center[1] + (aspect*max_width)*[-.5, .5]

    endelse

    img_pos = [xrange[0], yrange[0], xrange[1], yrange[1]]

    img = image(dat, CURRENT = current, POSITION = img_pos)

    oImages.add, img

    ;get the original scale factors, scale centers, and positions

    file_hash['SCALE_CENTER'] = img.SCALE_CENTER

    file_hash['SCALE_FACTOR'] = img.SCALE_FACTOR

    file_hash['POSITION'] = img.POSITION

    file_hash['XRANGE'] = img.XRANGE

    file_hash['YRANGE'] = img.YRANGE

   

    ;default rotation to 0

    file_hash['ROTATION'] = 0

    ;save the image information

    info_hash[strlowcase(drawfile)] = file_hash

  endif else begin

    print, 'Image drawn already, skipping...'

  endelse

end

 

pro ImageInfo::DeselectAllImages

  compile_opt idl2

  ;disable window update

  self.oWin.Refresh, /disable

  foreach img, self.oImages do img.Select, /CLEAR

  ;refresh the window

  self.oWin.Refresh

end

pro Imageinfo::ResetImages

  compile_opt idl2

  ;get the reference to the images that are selected

  oImages = self.oImages

  ;disable window update

  self.oWin.Refresh, /disable

  selected = self.oWin.GetSelect()

  keys = self.ImageHash.keys()

  foreach img, selected do begin

    idx = (where(img eq self.oImages.toarray()))[0]

    ;reset rotation

    img.rotate, /reset

    ;return properties to their initial values

    img.SCALE_CENTER = (self.ImageHash[keys[idx]])['SCALE_CENTER']

    img.SCALE_FACTOR = (self.ImageHash[keys[idx]])['SCALE_FACTOR']

    img.XRANGE = (self.ImageHash[keys[idx]])['XRANGE']

    img.YRANGE = (self.ImageHash[keys[idx]])['YRANGE']

    img.POSITION = (self.ImageHash[keys[idx]])['POSITION']

    img.POSITION = (self.ImageHash[keys[idx]])['POSITION']

    img.Order, /BRING_TO_FRONT

  endforeach

  ;refresh the window

  self.oWin.Refresh

end

pro ImageInfo::BringImagesForward

  compile_opt idl2

  foreach selected, self.oWin.GetSelect() do selected.Order, /BRING_FORWARD

end

pro ImageInfo::RemoveImages

  compile_opt idl2

  ;get the selected images

  selected = self.oWin.GetSelect()

  ;disable window update

  self.oWin.Refresh, /disable

  foreach img, selected do begin

    ;get the reference to the image list

    oImages = self.oImages

    oFiles = self.oFiles

    ;get the leftover hash keys

    keys = self.ImageHash.keys()

    ;figure out which image was clicked on

    idx = (where(img eq oImages.toarray()))[0]

    imageref = oImages[idx]

    ;delete graphics

    imageref.Delete

    ;remove reference from the list

    oImages.Remove, idx

    oFiles.Remove, idx

    ;remove the key from the hash

    self.ImageHash.Remove, keys[idx]

  endforeach

  ;refresh the display

  self.oWin.Refresh

end

pro ImageInfo::ResetImageRotations

  compile_opt idl2

  ;get the reference to the images that are selected

  oImages = self.oImages

  imagehash = self.imagehash

  keys = imagehash.keys()

  ;disable window update

  self.oWin.Refresh, /disable

  selected = self.oWin.GetSelect()

  foreach img, selected do begin

    ;find the index for which image is selected

    img_idx = (where(oImages.toarray() eq img))[0]

    ;reset rotation in the iamge hash

    (imagehash[keys[img_idx]])['ROTATION'] = 0

    ;reset rotation

    img.rotate, /reset

  endforeach

  ;refresh the window

  self.oWin.Refresh

end

pro Imageinfo::ResetImageZooms

  compile_opt idl2

  ;get the reference to the images that are selected

  oImages = self.oImages

 

  ;disable window update

  self.oWin.Refresh, /disable

  selected = self.oWin.GetSelect()

  keys = self.ImageHash.keys()

  foreach img, selected do begin

    idx = (where(img eq self.oImages.toarray()))[0]

    ;return properties to their initial values

    img.SCALE_CENTER = (self.ImageHash[keys[idx]])['SCALE_CENTER']

    img.SCALE_FACTOR = (self.ImageHash[keys[idx]])['SCALE_FACTOR']

    img.XRANGE = (self.ImageHash[keys[idx]])['XRANGE']

    img.YRANGE = (self.ImageHash[keys[idx]])['YRANGE']

  endforeach

  ;refresh the window

  self.oWin.Refresh

end

pro ImageInfo::RotateImages, theta

  compile_opt idl2

  ;get the reference to the images that are selected

  oImages = self.oImages

  ;disable window update

  self.oWin.Refresh, /disable

  selected = self.oWin.GetSelect()

  keys = self.ImageHash.keys()

  foreach img, selected do begin

    ;figure out which image was clicked on

    idx = (where(img eq self.oImages.toarray()))[0]

    imagehash = self.ImageHash[keys[idx]]

    imageref = oImages[idx]

    ;reset the image, rotate by theta

    imageref.Rotate, /RESET

    imagehash['ROTATION']+=theta

    imageref.Rotate, imagehash['ROTATION']

  endforeach

  self.oWin.Refresh

end

pro ImageInfo::SelectAllImages

  compile_opt idl2

  ;disable window update

  self.oWin.Refresh, /disable

  foreach img, self.oImages do img.Select, /ADD

  ;refresh the window

  self.oWin.Refresh

end

pro ImageInfo::SendImagesBack

  compile_opt idl2

  foreach selected, self.oWin.GetSelect() do selected.Order, /SEND_BACKWARD

end

 

;method to convert iamges to ENVI formatted files, OUTFILES is not an input keyword, but output

pro ImageInfo::StitchImages, DOWNSIZE = downsize, OUTFILES = outfiles

  compile_opt idl2

  ;select all of the images that are displayed

  images = self.oImages.toarray()

  files = self.oFiles.toarray()

  keys = self.ImageHash.keys()

 

  ;make sure we have some images to process

  if (n_elements(files) gt 0) then begin

    outfiles = strarr(n_elements(images))

    ;start ENVI

    e = envi(/current)

    if (e eq !NULL) then begin

      e = envi(/headless)

      nokill = 1

    endif

    ; create ENVI formatted files

    print, 'Converting images to ENVI formatted files...'

    for i=0,n_elements(images)-1 do begin

      img = images[i]

      pos = img.position

      top_left = [pos[0], pos[3]] - .5d

      imagehash = self.imagehash[keys[i]]

      dims = imagehash['DIMS']

      dims_2d = dims[where(dims ne 3)]

      pix_size = [pos[2] - pos[0],pos[3] - pos[1]]/(dims_2d/downsize)

      outfile = strmid(files[i], 0, strpos(files[i],'.', /REVERSE_SEARCH)) + '_envi.dat'

      ;check if file exists and delete it

      if file_test(outfile) then FILE_DELETE, outfile, /QUIET

      ;if it still exists after deleting, then another program has a lock on the file

      if file_test(outfile) then begin

        print, 'File "' + outfile + '" locked by another program, skipping...'

        continue

      endif

      outfiles[i] = outfile

      dat = read_image(files[i])

      dims = size(dat, /DIMENSIONS)

      nchannels=1

      ;change interleave to BSQ

      if (n_elements(dims) gt 2) then begin

        nchannels = min(dims)

        channel = (where(dims eq nchannels))[0]

        ;change image interleave to BSQ

        case channel of

          0:dat = transpose(dat, [1,2,0])

          1:dat = transpose(dat, [0,2,1])

          2:;do nothing

        endcase

        dims = size(dat, /DIMENSIONS)

      endif

      ;resize the image if needed

      if (downsize gt 1) then begin

        if (nchannels eq 1) then begin

          dat = congrid(dat, floor(dims[0]/downsize), floor(dims[1]/downsize), /INTERP)

        endif else begin

          dat = congrid(dat, floor(dims[0]/downsize), floor(dims[1]/downsize), nchannels, /INTERP)

        endelse

      endif

      ;rotate the image if the user rotated the image with the degree buttons

      if (imagehash['ROTATION'] ne 0) then begin

        print, string(9b) + 'Rotating image, may take a minute or two depending on size...'

        dat = RotateImage(dat, imagehash['ROTATION'])

      endif

      ;assume the number of channels is the smallest dimension

      ;if we have more than one, then we need to account for interleave change to BSQ

      if (n_elements(dims) eq 2) then begin

        nchannels = 1

        ;rotate image to have ENVI orientation

        dat = rotate(dat, 7)

      endif else begin

        nchannels = min(dims)

        channel = (where(dims eq nchannels))[0]

        ;change image interleave to BSQ

        case channel of

          0:dat = transpose(dat, [1,2,0])

          1:dat = transpose(dat, [0,2,1])

          2:;do nothing

        endcase

        for z=0,nchannels-1 do begin

          dat[*,*,z] = rotate(reform(dat[*,*,z]),7)

        endfor

      endelse

     

      ;create a spatial reference

      spatialref = ENVIStandardRasterSpatialRef($

        coord_sys_code = 4326, $

        /GEOGCS,$

        pixel_size = pix_size, $

        tie_point_pixel = [0, 0], $

        tie_point_map = top_left)

      newraster = ENVIRaster(dat, URI = outfile, SPATIALREF = spatialref)

      ;add a data ignore value if we had rotation

      if (imagehash['ROTATION'] ne 0) then begin

        newraster.METADATA.AddItem, 'data ignore value', 0

      endif

     

      ;save and close the raster

      newraster.save

      newraster.close

      print, string(9b) + 'Converted ' + strtrim(i+1,2) + ' of 'strtrim(n_elements(images),2) + ' images, outfile:'

      print, string(9b) + string(9b) + outfile

    endfor

    ;close ENVI if we started it during this method

    if (nokill eq !NULL) then e.close

  endif else begin

    print, 'No images selected, returning'

    return

  endelse

end

pro ImageInfo__define

  compile_opt idl2

  struct = {$

    IMAGEINFO,$

    ImageHash:orderedhash(),$

    oImages:list(),$

    oFiles:list(),$

    oWin:obj_new(),$

    max_width:1d}

end

function RotateImage, img_dat, theta

  compile_opt idl2, hidden

  ;get the data dimensions

  dims = size(img_dat, /DIMENSIONS)

  nchannels = 1

 

  if ~keyword_set(orientation) then orientation = 2

  ;apply rotation for nchannel images

  ndims = n_elements(dims)

  if (ndims gt 2) then begin

    nchannels = min(dims)

    channel = (where(dims eq nchannels))[0]

    ;change image interleave to BSQ

    case channel of

      0:img_dat = transpose(img_dat, [1,2,0])

      1:img_dat = transpose(img_dat, [0,2,1])

      2:;do nothing

    endcase

    dims = size(img_dat, /DIMENSIONS)

  endif

  ;calculate our rotation matrix

  theta*=!DTOR

  r_mat = [[ cos(theta), sin(theta), 0],$

    [-sin(theta), cos(theta), 0],$

    [     0     ,      0    , 0]]

  ;pre-allocate an array for the initial pixel locations

  xy0 = make_array(3, dims[0]*dims[1], TYPE = 12, /NOZERO)

  ;fill xy0 with values

  indices = lindgen(dims[0]*dims[1])

  xy0[0,*] = indices mod dims[0]

  xy0[1,*] = indices/dims[0]

  xy0[2,*] = replicate(1.0,1,dims[0]*dims[1])

  delvar, indices

  ;rotate our initial positions to find out the new pixel locations

  xy1 = matrix_multiply(r_mat, xy0)

  ;grab the individual xy new locations

  xind = xy1[0,*]

  yind = xy1[1,*]

  ;create output grid for out image

  xout = floor(xind.min()) + dindgen(ceil(xind.max() - xind.min()))

  yout = floor(yind.min()) + dindgen(ceil(yind.max() - yind.min()))

  ;use custom, amazing interpolation

  new_dims = [n_elements(xout), n_elements(yout)]

  out_dat = make_array(new_dims[0], new_dims[1], nchannels,TYPE = img_dat.typecode, VALUE = 0)

  for i=0, nchannels-1 do begin

    channel_dat = reform(out_dat[*,*,i])

    channel_dat[xind - xind.min(), yind-yind.min()] = img_dat[*,*,i]

    ;fill in missing holes

    zero = where(channel_dat eq 0, zero_count)

    if (zero_count gt 0) then begin

      for z=0, zero_count-1 do begin

        ;check if we have neighbors that are not equal to 0

        xidx = zero mod new_dims[0]

        yidx = zero / new_dims[0]

        for z=0, zero_count-1 do begin

          sub = channel_dat[xidx[z]-1 > 0:xidx[z]+1 < (new_dims[0]-1), yidx[z]-1 > 0:yidx[z]+1 < (new_dims[1]-1)]

          close_nozero = where(sub ne 0, nozero_count)

          if (nozero_count gt 6) then channel_dat[xidx[z],yidx[z]] = total(sub[close_nozero])/nozero_count

        endfor

      endfor

    endif

    out_dat[*,*,i] = channel_dat

  endfor

  ;remove any irrelevant indices

  return, reform(out_dat)

end

pro IDLMosaic_event, event

  ;help, event

  widget_control, event.top, get_uvalue=info

  ;get the image properties lists

  oImageInfo = info.oImageInfo

  ;turn on the hourglass

  widget_control, HOURGLASS=1

  ;check if we have a kill request event

  case TAG_NAMES(event, /STRUCTURE_NAME) of

    'WIDGET_KILL_REQUEST':BEGIN

      !except = info.orig_except

      WIDGET_CONTROL, event.top, /DESTROY

      retall

    END

    ELSE: ;do nothing

  endcase

  ;handle the event by the widget that was pressed

  case event.id of

    ;user double clicked on a list element for all of the images

    ;so we will draw it

    info.wList:begin

      if (event.CLICKS eq 2) then begin

        ;get the list of files

        files = info.files

        ;draw the image

        oImageInfo.AddImage, files[event.index], CURRENT = info.oWin

      endif

    end

    ;user wants to zoom out

    info.wZoomOut:begin

      info.oWin.ZoomOut

      info.oWin.Refresh

    end

    ;user wants to zoom in

    info.wZoomIn:begin

      info.oWin.ZoomIn

      info.oWin.Refresh

    end

   

    ;bring selected items forward

    info.wBringForward:begin

      info.oImageInfo.BringImagesForward

    end

    ;send selected items forward

    info.wSendBack:begin

      info.oImageInfo.SendImagesBack

    end

    ;reset the image to have all of its original properties

    info.wResetImage:begin

      info.oImageInfo.ResetImages

    end

    ;reset the image zoom only

    info.wResetZoom:begin

      info.oImageInfo.ResetImageZooms

    end

    ;reset the image rotation

    info.wResetRotation:begin

      info.oImageInfo.ResetImageRotations

    end

    ;deselect all images

    info.wDeselectAll:begin

      info.oImageInfo.DeselectAllImages

    end

    ;select all images

    info.wSelectAll:begin

      info.oImageInfo.SelectAllImages

    end

    ;remove selected images

    info.wDeleteImage:begin

      info.oImageInfo.RemoveImages

    end

    ;images are rotated

    info.wRotCSmall:begin

      info.oImageInfo.RotateImages, 0.2

    end

    info.wRotCCSmall:begin

      info.oImageInfo.RotateImages, -0.2

    end

    info.wRotCMedium:begin

      info.oImageInfo.RotateImages, 1.0

    end

    info.wRotCCMedium:begin

      info.oImageInfo.RotateImages, -1.0

    end

    info.wRotCLarge:begin

      info.oImageInfo.RotateImages, 5.0

    end

    info.wRotCCLarge:begin

      info.oImageInfo.RotateImages, -5.0

    end

    ;convert images to ENVI formatted files

    info.wStitchImages:begin

      info.oImageInfo.StitchImages, DOWNSIZE = info.downsize, OUTFILES = outfiles

      ;check if the ENVI workbench is open, if so then ask if the user wants to open up the images

      ;if ENVI is not open, then open it now

      msg = dialog_message('Would you like to open the ENVI workbench and display the images in ENVI?', /QUESTION)

      if (msg eq 'Yes') then begin

        e = envi(/current)

        if (e eq !NULL) then begin

          e = envi()

        endif else begin

          ;open up the ENVI Workbench if not open already

          if (e.widget_id eq 0) then begin

            e.close

            e = envi()

          endif

        endelse

        ;disable ENVI Workbench update

        e.refresh, /disable

        ;add each image to ENVI's view

        view = e.GetView()

        foreach file, outfiles do begin

          if (file eq '') then continue

          raster = e.openraster(file)

          layer = view.createlayer(raster)

        endforeach

        ;refresh ENVI display

        e.refresh

      endif

      ;destroy the widget

      WIDGET_CONTROL, event.top, /DESTROY

    end

    ;user resized the base

    info.wBase:begin

      widget_control, info.wDraw, xSize=event.y, ySize=event.y

    end

    else:;print, 'dunno what to do with id ', event.id

  endcase

  widget_control, HOURGLASS=0

end

;+

;

;

; :Keywords:

;    DOWNSIZE: in, optional, type=int, default=4

;       Set this keyword to an integer which represents the resize factor when the

;       iamges are created as ENVI formatted files. For example, setting this keyword to 3

;       will regrid the results to have 1/3 the X and Y dimensions that they originally have.

;    EXTENSION: in, optional, type=string, default='jpg'

;       This keyword represents the file extensions that will be searched for if you set the

;       `PICKDIR` keyword.

;    MAX_WIDTH: in, optional, type=float, default=.33, min=.1, max=.5

;       Setting this keyword will control the maximum size that an image can be when added to

;       the widget. Setting this value to a smaller number will allow for more images to be added

;       to the display.

;    PICKDIR: in, optional, type=sting

;       This optional keyword can be set to a directory that contains images you want to use

;       with IDLMosaic. The directory that this keyword is set to will be searched for files

;       ending with `EXTENSION`. Make sure you change

;

; :Author: Norm3596

;-

pro IDLMosaic, DOWNSIZE = downsize, EXTENSION = extension, MAX_WIDTH = max_width, PICKDIR = pickdir

  compile_opt idl2

  ireset, /no_prompt

  ;select a directory of files

  if keyword_set(pickdir) then begin

    if (extension eq !NULL) then extension = 'jpg'

    if ~file_test(pickdir) then message, 'PICKDIR specified, but directory does not exist!'

    cd, pickdir, CURRENT = first_dir

    files = file_search('*' + extension, COUNT=nfiles)

    cd, first_dir

    if (nfiles eq 0) then message, 'No files found with extension!'

 

    ;sort the found files and prepend the input directory

    files = (pickdir + path_sep() + files).sort()

  ;default is to use dialog pickfile to select images

  endif else begin

    ;use dialog pickfile to select images

    files = dialog_pickfile(/MULTIPLE_FILES)

    nfiles = n_elements(files)

    if (files[0] eq '') then message, 'No files chosen!'

  endelse

  ;check if we want to downsample the rasters

  ;by default this is true because the size in a .dat file of a JPEG is much

  ;greater than just the jpeg image itself

  if keyword_set(downsize) then downsize = downsize else downsize = 4

  ;keyword for setting the maximum width of the iamges in the display window

  if ~keyword_set(max_width) then max_width = .33

  ;make suze max_width falls within realistic values to fit in our window

  max_width>=.1

  max_width<=.5

  ;create starting widgets

  wBase = widget_base(/row, title='IDLMosaic', tlb_size_events=0)

  ;create the draw widget

  window_size = [800, 800]

  wDraw = widget_window(wBase, xsize = window_size[0]+1, ysize = window_size[1]+1, $

    X_SCROLL_SIZE = window_size[0], Y_SCROLL_SIZE = window_size[1])

  wButtonCol = widget_base(wBase, /col)

  wStatus = widget_label(wButtonCol,  /dynamic_resize, value='Images:')

  ;create a list widget

  wList = widget_list(wButtonCol, VALUE = file_basename(files), YSIZE = nfiles<10)

  ;crete buttons for zooming in and out

  wZoomIn = widget_button(wButtonCol, /dynamic_resize, value='Zoom In')

  wZoomOut = widget_button(wButtonCol, /dynamic_resize, value='Zoom Out')

  ;reset the view for the image

  wImageText = widget_label(wButtonCol, value='Image Actions:')

  wResetImage = widget_button(wButtonCol, /dynamic_resize, value='Reset Properties')

  wResetZoom = widget_button(wButtonCol, /dynamic_resize, value='Reset Zoom')

  wResetRotation = widget_button(wButtonCol, /dynamic_resize, value='Reset Rotation')

 

  ;crete buttons for zooming in and out

  wBringForward = widget_button(wButtonCol, /dynamic_resize, value='Bring Forward')

  wSendBack = widget_button(wButtonCol, /dynamic_resize, value='Send Back')

  ;add buttons for rotating the images

  wRotateClockwise = widget_label(wButtonCol, value='Rotate Clockwise:')

  wBaseClockwise = widget_base(wButtonCol, /ROW, /ALIGN_CENTER)

  wRotCSmall = widget_button(wBaseClockwise, /dynamic_resize, value='0.2')

  wRotCMedium = widget_button(wBaseClockwise, /dynamic_resize, value='1.0')

  wRotCLarge = widget_button(wBaseClockwise, /dynamic_resize, value='5.0')

  wRotateCounterClockwise= widget_label(wButtonCol, value='Rotate Counter-clockwise:')

  wBaseCClockwise = widget_base(wButtonCol, /ROW, /ALIGN_CENTER)

  wRotCCSmall = widget_button(wBaseCClockwise, /dynamic_resize, value='0.2')

  wRotCCMedium = widget_button(wBaseCClockwise, /dynamic_resize, value='1.0')

  wRotCCLarge = widget_button(wBaseCClockwise, /dynamic_resize, value='5.0')

  ;crete buttons for zooming in and out

  wSelectAll = widget_button(wButtonCol, /dynamic_resize, value='Select All')

  wDeselectAll = widget_button(wButtonCol, /dynamic_resize, value='Deselect All')

  wDeleteImage = widget_button(wButtonCol, /DYNAMIC_RESIZE, VALUE='Remove Images')

  wStitchImages = widget_button(wButtonCol, /DYNAMIC_RESIZE, VALUE='Done!')

  widget_control, wBase, /realize

  ; Retrieve the newly-created Window object.

  widget_control, wDraw, get_value=oWin

  ;remember the original valu of !EXCEPT

  orig_except = !EXCEPT

  !EXCEPT=0

 

  info = {$

    wBase:wBase,$

    wDraw:wDraw,$

    wStatus:wStatus,$

    wList:wList,$

    wZoomOut:wZoomOut,$

    wZoomIn:wZoomIn,$

    wBringForward:wBringForward,$

    wSendBack:wSendBack,$

    wResetImage:wResetImage,$

    wResetZoom:wResetZoom,$

    wResetRotation:wResetRotation,$

    wSelectAll:wSelectAll,$

    wDeselectAll:wDeselectAll,$

    wDeleteImage:wDeleteImage,$

    wStitchImages:wStitchImages,$

    wRotCSmall:wRotCSmall,$

    wRotCCSmall:wRotCCSmall,$

    wRotCMedium:wRotCMedium,$

    wRotCCMedium:wRotCCMedium,$

    wRotCLarge:wRotCLarge,$

    wRotCCLarge:wRotCCLarge,$

    oWin:oWin,$

    oImageInfo:ImageInfo(oWin),$

    except_orig:orig_except,$

    files:files,$

    downsize:downsize,$

    max_width:max_width}

   

  ;set the uvalue

  widget_control, wBase, set_uvalue=info

  ;register the widget with our event handler

  ;keep this widget as blocking

  xmanager, 'IDLMosaic', wBase, /NO_BLOCK

end