An introduction to X Window application development.

80 Pages·1.2 MB·en_US

by  Rust, David Michael.;Sengupta, Kishore.

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CURITYCLASSIFICATIONOFTHISPAGE
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^1.NTIITLNET(IRncOluDdeUSeCcuTriItyOCNlassTifOicatXionW) INDOWAPPLICATIONDEVELOPMENT(U)
2 PERSONALAUTHOR(S)
lust,DavidM.
3a.typeofreport 13b.timecovered 14.DATEOFREPORT(Year,Month,Day) 16.PAGECOUNT
Master'sThesis from 10/90 to 03/92 1992^,March,23 70
6 supplementarynotation Theviewsexpressedinthis^sis thoseoftheauthormddonotreflecttheofficial
policyorpositionoftheDepartmentofDefenseortheUnited StatesGovernment.
COSATICODES 18.SUBJECTTERMS(Continueonreverseifnecessaryandidentifybyblocknumber)
FIELD GROUP SUB-GROUP tCooomlkpiutts,erwiPdrgeotg,rawmimnidnogw,,GwrianpdhiocwailngUsseyrstIenmte,rfXalcieb,,pXorWtaibnldeoswystems,
9 ABSTRACT(Continueonreverseifnecessaryandidentifybyblocknumber)
Thechallengetodevelopingapplicationsforcomputer-basedwindowingsystemsisgeneratingcodeforthegraph-
;alinterfaceelements. Eachwindowingsystemoffersitsownsetofprotocolsforbuildingthegraphicalunits,but
leseprotocolsarerarelyportableacrossdifferenthardwareplatforms.TheXWindowSystemtranscendsmanyof
leseincompatibilitiesandoffersastandardforcreatinggraphics.Itisoperatingsystemandnetworkindependent,
lowever,thebasicprogramminglibraryforXWindowofferslittlesophisticationforanapplication'sgraphicalin-
^rfacedevelopment. HigherleveltoolsmakeupfortheshortcomingsofthegenericXWindowSystem,
'histhesisconvertsanExpertSystemKnowledgeAcquisitionandPolicyEvaluationprogramusingCognitiveFeed-
ack(ESKAPE/CF)fromtheSunViewwindowingsystemtoXWindow.Thenewapplication,calledXESKAPE/CF,
ontainsthesamefunctionalityastheoriginalprogrameven thoughthemigrationfromSunViewtoXWindowre-
uiredanextensivereworkingoftheprogram'sinterfacecode.ThethesisalsoextendsthebasicXWindowlibrary
ffunctionswithmoreadvancedobjects.TheseobjectsofferadditionalfunctionalitytotheXESKAPE/CFapplica-
on'sinterface.
)X]DIUSNTCRLIABSUSTIIFOINE/DA/VUAINLLAIBMIILTIETDYOQFASBASTMREAACSTRPT. [JDTICUSERS 21U.NACBSLTARSACSTISFEICUERDITYCLASSIFICATION
a.NAMEOFRESPONSIBLEINDIVIDUAL 22b.TELEPHONE(IncludeAreaCode) 22c.OFFICESYMBOL
ishoreSengupta [phone] AS/Se
)FORM1473,84MAR 83APReditionmaybeuseduntilexhausted SECURITYCLASSIFICATIONOFTHISPAGE
Allothereditionsareobsolete UNCLASSIFIED
torQ LL
1
Approvedforpublicrelease;distributionisunlimited
AnIntroductiontoXWindowApplicationDevelopment
by
DavidMichaelRust
Lieutenant,UnitedStatesNavy
B.S.,RiceUniversity, 1986
Submittedinpartialfulfillmentofthe
requirementsforthedegreeof
MASTER OFSCIENCEININFORMATIONSYSTEMS
fromthe
NAVALPOSTGRADUATESCHOOL
March 1992
ABSTRACT
The challengeto developing applications forcomputer-basedwindowing systemsis
generating code for the graphical interface elements. Each windowing system offers its
ownsetofprotocolsforbuildingthegraphicalunits,buttheseprotocolsarerarelyportable
across different hardware platforms. The X Window System transcends many of these
incompatibilities and offers a standard for creating graphics. It is operating system and
networkindependent. However,thebasicprogramminglibraryforXWindowofferslittle
sophistication for an application's graphical interface development. Higher level tools
makeupfortheshortcomingsofthegenericXWindow System.
ThisthesisconvertsanExpertSystemKnowledgeAcquisitionandPolicyEvaluation
program using CognitiveFeedback (ESKAPE/CF) fromthe SunViewwindowing system
toXWindow.Thenewapplication,calledXESKAPE/CF,containsthesamefunctionality
as the originalprogrameven though themigration from SunView toXWindowrequired
an extensivereworkingoftheprogram'sinterfacecode. Thethesis alsoextendsthebasic
XWindowlibraryoffunctionswithmoreadvancedobjects.Theseobjectsofferadditional
functionalitytotheXESKAPE/CFapplication'sinterface.
TABLE OFCONTENTS
INTRODUCTION
I. 1
A. THESIS OBJECTIVESANDSCOPE 1
B. BACKGROUND 2
C. ORGANIZATIONOFTHESTUDY 2
D. DISCLAIMER 3
II. XWINDOWPROGRAMMINGLAYERS 4
A. PROGRAMMINGINXWINDOW 4
1. Widgets 4
2. ToolkitHierarchy 4
B. XLIB:THEXWINDOWLIBRARY 5
C. MIDDLELEVELTOOKITS 5
1. Intrinsics 6
a. Xt: TheXToolkit 6
b. Xaw:TheAthenaWidgetSet 6
2. XView 6
D. HIGHLEVELTOOLKITS 7
1. OpenLookIntrinsicsToolkit(OLIT) 7
2. Motif 7
III. ANINTRODUCTIONTOXLIBPROGRAMMINGTECHNIQUES 8
A. GETTING STARTED 9
1. ConnectingtheClienttotheServer 9
2. LinkingtoaScreen 9
.lUDLbYKNOXLIBRARY
NAVALPOSTGRADUATESCHOOL
MONTEREY.CALIFORNIA93943-5002
3. LoadingFonts 10
B. USINGWINDOWS 10
1. CreatingWindows 10
2. TheGraphicsContext 12
3. MappingWindows 12
4. DrawingInsidetheWindow 13
C. EVENTLOOPPROCESSING 13
1. HandlingUserInput 14
2. RefreshingtheScreen 15
IV. XESKAPE/CF:THEXWINDOWVERSIONOFESKAPE/CF 16
A. FUNCTIONALCOMPARISONTOESKAPE/CF 16
B. MOTIVATIONFORTHEPROGRAMCONVERSION 19
C. INITIALAPPROACHTOTHEPROGRAMCONVERSION 19
D. MAINPROGRAMCONTROL:THEEVENTLOOP 20
E. BUILDINGWIDGETS 23
1. InteractiveText 23
a. CreatingtheWidget 25
b. TyingtheWidgettotheEventLoop 26
c. UsingtheWidgetIntheXESKAPE/CFProgTam 32
2. StaticText 35
3. Buttons 37
V. CONCLUSIONSANDRECOMMENDATIONS 39
A. ENVIRONMENTALCONSIDERATIONS 39
1. Portability 39
V
2. InterfaceConsistency 39
B. APPLICATIONCONSIDERATIONS 40
1. Application Size 40
2. ProgrammingExperience 40
APPENDIXA: THEHISTORYOFXWINDOW 41
APPENDIXB:THESTRUCTUREOFXWINDOW 43
APPENDIXC: THEGETTEXTWIDGET 47
APPENDIXD: GLOSSARYOFTERMS 57
LISTOFREFERENCES 60
BIBLIOGRAPHY 62
INITIALDISTRIBUTIONLIST 63