Computing for Imaging Science SIMG726

1
Computing for Imaging Science (SIMG-726)
2
Gift Quiz - Who is RTM?

• What did his father do?

3
Syllabus after Holiday Break

• Class 6 - Today
• Widget Programming Review
• Assignment 2 (Check Website for details)
• Combine Assignment 1 into Assignment 2
• Create a widget program that will read in a PGM
  file that will display the image statistics of a
  user defined rectangular region.
• Pay particular attention to non-interactive
  interface
• Program the one-dimensional and two-dimensional
  special functions Rect and Gaus

4
Syllabus

• Class 7
• Widget Programming
• Event Handlers

5
Syllabus

• Class 8
• Assignment 1 Due
• Shell Programming
• UNIX Quotes
• Making UNIX commands of IDL Programs
• Mystery Image Techniques
• QUIZ
• Topics
• dd, od, strings, which, wc

6
Syllabus

• Class 9
• Debugging in IDL
• More Widget Examples

7
Syllabus

• Class 10
• Special Function Implementation
• Midterm Exam Review
• Quiz

8
Syllabus

• Class 11
• Midterm Exam (Take home 1 week to do)
• Image Processing Implementations

9
Syllabus

• Class 12
• Image Processing Implementations
• AWK, SED, and Makefiles
• Quiz

10
Syllabus

• Class 13
• Final Project Updates
• IDL Pointers

11
Syllabus

• Class 14
• Assignment 2 Due
• Modal Widgets

12
Syllabus

• Class 15
• 3D Graphics Concepts

13
Syllabus

• Class 16
• More 3D Graphics

14
Syllabus

• Class 17
• Open Class Time for Project Consulting

15
Syllabus

• Class 18
• Project Presentation Session 1

16
Syllabus

• Class 19
• Project Presentation Session 2
• Final Project Submissions Due

17
Widget Events
18
Widget Event

• A widget event is basically a reaction to some
  form of user input
• Mouse clicks, drags, and movement
• Keyboard input
• Button push
• An widget event generates a structure which
  identifies the widget that caused the event and
  other relevant information.

19
IDL Event Structure

• All IDL Events will generate a named structure
  that is guaranteed to have the following
• A structure name
• The ID of the widget that generated the event
• The ID of the base to which the above widget
  belongs
• The ID of the widget with which an event handler
  is associated.

20
Event Handler

• Special Processing functions (Event Handlers)
• capture and appropriately interpret those events.
• single button program
• beep when pressed.
• First, need to create and destroy a widget by
  creating a Quit Button

21
Create the Quit Button Widget

• pro quit_button
• baseWidget_Base(column1,titleQuit Button)
• button Widget_Button( base, valueQuit )
• Widget_Control, base, /realize
• end

22
Quit Button Widget Event HandlerMethod 1

• pro quit_button_event, event
• Widget_Control, event.top, /destroy
• end
• pro quit_button
• baseWidget_Base(column1,titleQuit Button)
• button Widget_Button( base, valueQuit)
• Widget_Control, base, /realize
• Xmanager, quit_button', base,
  event_handlerquit_button_event'
• end

23
Quit Button Widget Event Handler Method 2

• pro quitter, event
• Widget_Control, event.top, /destroy
• end
• pro quit_button_event, event
• end
• pro quit_button
• baseWidget_Base(column1,titleQuit Button)
• buttonWidget_Button(base, valueQuit,
  event_proquitter )
• Widget_Control, base, /realize
• Xmanager, quit_button', base,event_handlerqui
  t_button_event'
• end

24
Button Widget Example

• For the sake of presentation space, we will not
  be including the quit button in the following
  code.
• You should, however, include it so that you can
  gracefully get rid of the widgets.

25
Create the Button Widget

• pro beeper
• baseWidget_Base(column1, title"Beep" )
• buttonWidget_Button(base,value"Press Here")
• Widget_Control, base, /realize
• end

26
Button Widget Event Handler

• pro beeper_event, event
• print,"Beep",string(7B)
• end
• pro beeper
• baseWidget_Base( column1, title"Beep" )
• buttonWidget_Button(base,value"Press Here")
• Widget_Control, base, /realize
• Xmanager, 'beeper', base, event_handler'beeper_
  event'
• end

27
If Your Widget Program Crashes

• First type
• IDLgt RETALL
• Followed by
• IDLgt XMANAGER
• You may then edit and recompile as necessary

28
Analyzing the Beep Event Handler

• You can strategically put help and print commands
  in beep_event and beep to study the values of the
  variables and the resulting structures.
• When pressed, the word Beep should print out in
  the IDL command window.

29
Beep Counter

• Let us modify the event handler to count the
  number of times we depressed the button during a
  session
• An initial solution might be the following

30
Wrong Beep Counter

• pro beeper_event, event
• count count 1
• print,Beeped , count, Times
• end
• pro beeper
• baseWidget_Base(column1, title"Beep")
• buttonWidget_Button(base,value"Press Here")
• Widget_Control, base, /realize
• Xmanager, 'beeper', base, event_handler'beeper_
  event'
• end

31
It Does Not Work Because...

• The scope of most of the variables (e.g. count)
  are local to each of the routines.
• We need a mechanism to maintain, pass, and keep
  variables persistent across events and routines.
• This can be done using the uvalue of a given
  widget as in the following.

32
Working Beep Counter

• pro beeper_event, event
• Widget_Control,event.id,get_uvaluecount
• count count 1
• print,"Beeped ", count, " Times"
• Widget_Control,event.id,set_uvaluecount
• end
• pro beeper
• base Widget_Base( column1, title"Beep" )
• button Widget_Button( base, value"Press
  Here" )
• Widget_Control, base, /realize
• Widget_Control,button,set_uvalue0
• Xmanager, 'beeper', base, event_handler'beeper_
  event'
• end

33
An Improved Beep Counter

• pro beeper_event, event
• Widget_Control, event.id, get_uvaluecount
• count count 1
• Widget_Control, event.id, set_uvaluecount
• Widget_Control, event.id, set_valuestring(coun
  t)
• end
• pro beeper
• base Widget_Base( column1, title"Beep" )
• button Widget_Button( base, value"Press
  Here" )
• Widget_Control, base, /realize
• Widget_Control, button, set_uvalue0
• Xmanager, 'beeper', base, event_handler'beeper_
  event'
• end

34
Beep Counter Controlling a Text Widget

• pro beeper_event, event
• Widget_Control, event.id, get_uvaluecount
• count count 1
• Widget_Control, event.id, set_uvaluecount
• Widget_Control, event.top, get_uvaluewidget_id
• Widget_Control, widget_id, set_valuestring(coun
  t)
• end
• pro beeper
• base Widget_Base( column1, title"Beep" )
• button Widget_Button( base, value"Press
  Here" )
• text Widget_Text( base )
• Widget_Control, base, /realize
• Widget_Control, base, set_uvaluetext
• Widget_Control, button, set_uvalue0
• Xmanager, 'beeper', base, event_handler'beeper_
  event'
• end

35
Beeper Counter using Text Widget

• In this situation, we use the uvalue of the base
  widget as a container to hold the ID of the text
  widget.
• We can now access this information from any
  widget that is contained in this base through the
  event.top field

36
Slider Multiply Example

• Create two floating sliders and multiply the
  values and deposit this in a text widget.
• Make the floating point widgets editable

37
Slider Multiply Widget Definition

• pro fslider_multiply
• baseWidget_Base(column1)
• fslider1 CW_Fslider(base,/edit)
• fslider2 CW_Fslider( base,/edit )
• text Widget_Text( base )
• Widget_Control, base, /realize
• widget_ids slider1fslider1,
  slider2fslider2, texttext
• Widget_Control, base, set_uvaluewidget_ids
• end

38
Slider Multiply Event Handler Definition

• pro fslider_multiply
• baseWidget_Base(column1)
• fslider1 CW_Fslider(base,/edit)
• fslider2 CW_Fslider( base,/edit )
• text Widget_Text( base )
• Widget_Control, base, /realize
• widget_ids slider1fslider1,
  slider2fslider2, texttext
• Widget_Control, base, set_uvaluewidget_ids
• Xmanager, 'fslider_multiply', base,
  event_handler'fslider_multiply_event'
• end

39
Slider Multiply Event Handler Definition

• pro fslider_multiply_event, event
• Widget_Control, event.top, get_uvaluewidgets
• slider1 widgets.slider1
• slider2 widgets.slider2
• text widgets.text
• Widget_Control, slider1, get_valueslider1_value
  
• Widget_Control, slider2, get_valueslider2_value
  
• answer slider1_value slider2_value
• Widget_Control, text, set_valuestring(answer)
• end

40
Another Widget Example
41
Display PGM Widget Program

• Illustrates the use of the pickfile function
• Shows how to create a draw widget for image
  display
• Shows how to access the draw widget and display
  the image

42
Components of Display PGM Widget

• read_pgm procedure
• pickfile function
• size function
• wset procedure
• tv procedure
• widget_control procedure
• widget_draw function
• xmanager procedure

43
Display PGM Widget Definition

• pro simple_image_display
• base Widget_Base( column1 )
• button1Widget_Button(base,value'Display PGM
  Image')
• window1 Widget_Draw(base, xsize256,
  ysize256 )
• Widget_Control, window1, /realize
• Widget_Control, window1, get_valuewindow_id
• Widget_Control, base, set_uvaluewindow_id
• Xmanager, 'simple_image_display', base,
  Event_handler'simple_image_display_event'
• end

44
Display PGM Widget
45
Widget Event Handler

• pro simple_image_display_event, event
• widget_control, event.id, get_valuewidget_value
  
• case widget_value of
• 'Display PGM Image' begin
• image1_file pickfile()
• read_ppm, image1_file, image1_data
• image_size size( image1_data )
• x_size image_size( 1 )
  y_sizeimage_size(2)
• widget_control, event.top,
  get_uvaluewindow_id
• wset, window_id tv,image1_data
• end
• ELSE
• endcase
• end

46
Pickfile Dialog Box
47
Resulting Widget Image Display
48
Summary

• Quit Button
• Beep Counter
• Slider Multiply
• PGM Display