Rolando V. RaqueñoJanuary 2006 1 Computing for Imaging Science (SIMG-726)

Rolando V. Raqueño January 200611

Computing for Imaging Science (SIMG-726)


QUIZ Next Class

• Reading Assignment Topics

• Topics– Grep, cd, RCS commands, chmod, mkdir


Assignment #1

• Check Wiki for Due Dates• Report must be generated using LaTeX

– Use report document class • Post LaTeX source and pdf file to wiki

– Topic name should be WikiNameAssignment1

– JohnSmithAssignment1


Assignment #1 (Continued)

• Change protection of Wiki topic page for – Viewing and Modification only by

• You and• RolandoRaqueno

– TRY IT ON A TEST PAGE FIRST!– Refer to Wiki Topic

People.HowToRestrictWikiTopicAccess• Lastly,

– Put a link to your assignment in your wiki home page


FINAL PRESENTATIONS

• PLEASE CHECK LINK ON CLASS WIKI• IT IS ON THE LAST DAY OF CLASS BUT

WILL START A EARLIER TO ACCOMMODATE EVERYONE

• PLEASE MAKE ARRANGEMENTS TO BE AVAILABLE

• LET ME KNOW OF ANY CLASS CONFLICTS


Assignment #2

• (Check WIKI for Due date details)– Combine Assignment #1 into Assignment

#2– Create a program that will read in a PGM

file that will display the image statistics of a user defined rectangular region.

– Program the one-dimensional and two-dimensional special functions Rect and Gaus


Widget Events


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.


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.


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


Create the Quit Button Widget

pro quit_button

base=Widget_Base(column=1,title=“Quit Button”) button = Widget_Button( base, value=“Quit” ) Widget_Control, base, /realize

end


Quit Button Widget Event Handler

Method #1pro quit_button_event, event Widget_Control, event.top, /destroyend

pro quit_button base=Widget_Base(column=1,title=“Quit Button”) button = Widget_Button( base, value=“Quit”) Widget_Control, base, /realize Xmanager, ’quit_button', base, event_handler=’quit_button_event'

end


Quit Button Widget Event Handler Method #2

pro quitter, event Widget_Control, event.top, /destroyendpro quit_button_event, eventendpro quit_button base=Widget_Base(column=1,title=‘Quit Button’) button=Widget_Button(base, value=‘Quit’, event_pro=‘quitter’ )

Widget_Control, base, /realize Xmanager, ’quit_button', base,event_handler=’quit_button_event'end


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.


Create the Button Widget

pro beeper

base=Widget_Base(column=1, title="Beep" ) button=Widget_Button(base,value="Press Here") Widget_Control, base, /realize

end


Button Widget Event Handler

pro beeper_event, event print,"Beep",string(7B)end

pro beeper base=Widget_Base( column=1, title="Beep" ) button=Widget_Button(base,value="Press Here") Widget_Control, base, /realize Xmanager, 'beeper', base, event_handler='beeper_event'

end


If Your Widget Program Crashes

• First type IDL> RETALL

• Followed byIDL> XMANAGER

• You may then edit and recompile as necessary


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.


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


Wrong Beep Counterpro beeper_event, event count = count + 1 print,”Beeped “, count, “ Times”end

pro beeper base=Widget_Base(column=1, title="Beep") button=Widget_Button(base,value="Press Here") Widget_Control, base, /realize Xmanager, 'beeper', base, event_handler='beeper_event'

end


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.


Working Beep Counterpro beeper_event, event

Widget_Control,event.id,get_uvalue=count count = count + 1 print,"Beeped ", count, " Times"

Widget_Control,event.id,set_uvalue=countend

pro beeper base = Widget_Base( column=1, title="Beep" ) button = Widget_Button( base, value="Press Here" ) Widget_Control, base, /realize

Widget_Control,button,set_uvalue=0 Xmanager, 'beeper', base, event_handler='beeper_event'end


An Improved Beep Counterpro beeper_event, event Widget_Control, event.id, get_uvalue=count count = count + 1

Widget_Control, event.id, set_uvalue=count Widget_Control, event.id, set_value=string(count)end

pro beeper base = Widget_Base( column=1, title="Beep" ) button = Widget_Button( base, value="Press Here" ) Widget_Control, base, /realize Widget_Control, button, set_uvalue=0 Xmanager, 'beeper', base, event_handler='beeper_event'end


Beep Counter Controlling a Text Widget

pro beeper_event, event Widget_Control, event.id, get_uvalue=count count = count + 1 Widget_Control, event.id, set_uvalue=count

Widget_Control, event.top, get_uvalue=widget_id Widget_Control, widget_id, set_value=string(count)end

pro beeper base = Widget_Base( column=1, title="Beep" ) button = Widget_Button( base, value="Press Here" ) text = Widget_Text( base ) Widget_Control, base, /realize

Widget_Control, base, set_uvalue=text Widget_Control, button, set_uvalue=0 Xmanager, 'beeper', base, event_handler='beeper_event'end


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


Slider Multiply Example

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

• Make the floating point widgets editable


Slider Multiply Widget Definition

pro fslider_multiply base=Widget_Base(column=1) fslider1 = CW_Fslider(base,/edit) fslider2 = CW_Fslider( base,/edit ) text= Widget_Text( base ) Widget_Control, base, /realize widget_ids = { slider1:fslider1, slider2:fslider2, text:text }

Widget_Control, base, set_uvalue=widget_idsend


Slider Multiply Event Handler Definition

pro fslider_multiply base=Widget_Base(column=1) fslider1 = CW_Fslider(base,/edit) fslider2 = CW_Fslider( base,/edit ) text= Widget_Text( base ) Widget_Control, base, /realize widget_ids = { slider1:fslider1, slider2:fslider2, text:text }

Widget_Control, base, set_uvalue=widget_idsXmanager, 'fslider_multiply', base, event_handler='fslider_multiply_event'

end


Slider Multiply Event Handler Definition

pro fslider_multiply_event, event Widget_Control, event.top, get_uvalue=widgets slider1 = widgets.slider1 slider2 = widgets.slider2 text = widgets.text Widget_Control, slider1, get_value=slider1_value Widget_Control, slider2, get_value=slider2_value answer= slider1_value * slider2_value Widget_Control, text, set_value=string(answer)end


Another Widget Example


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


Components of Display PGM Widget

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


Display PGM Widget Definition

pro simple_image_display base = Widget_Base( column=1 ) button1=Widget_Button(base,value='Display PGM Image') window1 = Widget_Draw(base, xsize=256, ysize=256 ) Widget_Control, window1, /realize Widget_Control, window1, get_value=window_id Widget_Control, base, set_uvalue=window_id Xmanager, 'simple_image_display', base,

Event_handler='simple_image_display_event'end


Display PGM Widget


Widget Event Handlerpro simple_image_display_event, event widget_control, event.id, get_value=widget_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_size=image_size(2) widget_control, event.top, get_uvalue=window_id

wset, window_id & tv,image1_data end ELSE: endcaseend


Pickfile Dialog Box


Resulting Widget Image Display


Summary

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

Documents

Rolando V. RaqueñoJanuary 2006 1 Computing for Imaging Science (SIMG-726)