外文翻译在PowerBuilder中处理图片文件的方法研究.docx

外文翻译在PowerBuilder中处理图片文件的方法研究.docx

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外文翻译在PowerBuilder中处理图片文件的方法研究

中文2696字

出处：

ComputerScienceandInformationTechnology,2009.ICCSIT2009.2ndIEEEInternationalConferenceon.IEEE,2009:

405-407

翻译部分

英文原文

StudyonmethodofpicturefilesprocessinginPowerBuilder

JiaYinjiangZhangTiejunZhaoJunying

Abstract—Picturesareoneoftheimportantelementsofwhichtheapplicationiscomposed.Aprogrammerisabletochoosesuitabletreatmentaccordingtothesystemrequirement.InPowerBuilderpicturecontrolandolecontrolarethemostcommonly-usedmethods;blobdatatypefieldisusedtoaccesspicturefilesindatabaseandfunctionofdatawindowisusedtodisplaypicturesdynamically.Eachmethodhasitsowncharacteristicsandapplicationconditions.ThisarticlediscussesandexploresthemethodsofstorageanddisplayofpicturefilesinPowerBuilder.

Keywords:

BlobDataType;PictureControl;Picture

Processing

I.INTRODUCTION

Picturesarecomposedofanimportantelementintheapplication.Flexibilityintheuseofthepicturewillmaketheproceduremoreattractive.Methodofpicturefilesprocessingmainlyincludespicturestorage,displayandupdate,etc.PowerBuilderinaccessthedatabaseanddataprocessinghasaverystrongfunctionbutweakinpicturestorageanddisplay.Aslongaswemastersomecommonly-useddevelopmentskills,wewillbeabletosolvepictureprocessingproblemwellinthepracticalapplication.

Picturesstoredintheformoffilecanbedisplayedwithpicturecontrolorolecontrol;picturesstoredinthedatabase,ablobdatatypefieldneededtobedefinedandpicturedatais

operatedwithbinarylargeobjectcommand.Inadditiontotheabovetwomethods,picturesalsocanbedisplayed

dynamicallybyusingofthemodifyfunctionofdatawindow.Eachmethodhasitsowncharacteristicsandapplication

conditions.ThisarticlediscussesandexploresthemethodsofstorageanddisplayofpicturefilesinPowerBuilder.

II.DISPLAYOFPICTUREFILES

A.PictureDisplaybyUseofPictureControl

InPowerBuilderusingpicturecontroliscommonmethodtodisplaythepicture.Itsupportsthepictureofthetypes

includeBMP,JPG,GIF,RLE,WMF,etc.Thefollowingmethodscanbeusedtodisplaypictures:

First,placeapicture

controlinthewindowandspecifytheselectedpicturebysettingits"picturename"staticproperty.Second,displaya

picturebysettingitspropertyinthescript,forexample,thescriptdisplayingpicturefile“jack.jpg”underthespecified

pathisp_1.picturename=”d:

\student\pic\jack.jpg”.Theabovetwomethodsareusedtodisplaytheabsolutepathof

thepictureways,thedisadvantageisthatpicturesmaynotbeabletodisplaycorrectlybecauseofthepathproblemafter

systemmigration.Third,displaypicturesbysettingrelativepathtosolvetheproblemoftheabsolutepath,modifyscript

codeforthep_1.picturename=”.\pic\jack.jpg”,weshouldpayattentiontothedifferencebetweenthetwomethods,thus,

pictureswillnotbedisappearedaftersystemmigration.

B.PictureDisplaybyUseofOleControl

Oleistheabbreviationofobjectlinkingandembeddingandrealizethroughremotecall,itisusedtotransferinformationfromoneapplicationtoanotheratacomputer.Olecontrolisthecontainerofcarryingoleobject.Displayingpictureswitholecontrol,firstplaceanolecontrolinPBwindow,andthenchoosepaintbrushpictureorbitmapimagetoshowthepictureoftheobjecttype,finallypicturescanbedisplayedwiththescriptaddedtotheprogram,suchasthefollowingstatementachievetoinsertanoleobjectnamed“peter”bitmapimage.ole_1.insertfile（“d:

\student\pic\peter.bmp”）

C.PictureDisplaybyUseFunctionofDataWindowModifyfunctionisaveryimportantfunctionofdatawindow,itismostfrequentlyfunctionusedwhileoperatingdatawindow.Thebasicsyntaxisasfollowing:

dw_controlname.modify（stringmodstring）Parametersmodstringdefinesmodificationofproperty.Userscanusetocreate,delete,andsetthepropertyvalueofthreetypesofstatementtodynamicallymodify.Forexample,placeadatawindowcontrolandacommandbuttonnamedchoosepicture,createadatawindowobjectandbindingadatawindowcontrol,inopeneventofthewindowenterthescriptcodeisasfollowing:

dw_1.settransobject（sqlca）

dw_1.retrieve（）

Scriptcodeinclickedeventofthecommandbuttonisasfollowing:

stringls_string,ls_fn

stringls_filepath,ls_filename

getfileopenname（"pleasechoosethepicturefiles",ls_filepath,ls_filename,"bmp","bmpfiles（*.bmp）,*.bmp,jpgfiles（*.jpg）,*.jpg,allfiles（*.*）,*.*"）

ls_fn=ls_filepath

ls_string='createbitmap（band=detailx="800"y="10"width="500"height="470"ls_filename="'+ls_fn+'"border="2"name=ls_pn）'

dw_1.modify（ls_string）

Runwindowandclickthecommandbutton,chooseapictureinthepop-updialogbox,theselectedpicturewillbedisplayedindetailbandofdatawindow,positionisx=800andy=10,picturesizeis500multiplied470pixels,borderstyleis2,thatis“stylebox”type.

Thismethodhasthefollowingcharacteristicsincomparisonwitholecontrolandpicturecontrolstyle:

First,datawindowfunctionscansupportmorefiletypeanddisplayavarietyoffiletypeformats,includingBMP,JPG,GIF,WMFImagefileformat,etc.Second,datawindowfunctionshavethecharacteristicsofflexibility,freedom,andcanbesetupinfunctionofpictureposition,size,border,displayarea,andotherproperty.Third,fasterimagesandlessmemory,picturesdisplayarenotplacedtosetacontrol,butdynamicallygeneratedintheprocessofprogramrunning.

III.PICTUREFILESACCESSINDATABASE

A.AccessPicturesthroughtheFilePath

Inordertoillustratetheoperationofpicturefiles,heretwotablesandtheirstructuredefinedaregivenbelow:

TABLEI.TABLETPB

ColumnNameDataTypeWidthNullRemark

Tpbhvarchar20NoPrimaryKey

tpljvarchar50Yes

TABLEII.TABLESTUDENT

ColumnNameDataTypeWidthNullRemark

xhvarchar10NoPrimaryKey

xmvarchar8No

xbvarchar2No

csrqdateYes

zplongbinaryYes

Inthisway,acharorvarchardatatypefieldwillbedefinedinthedatabase.Thisfieldisusedtoaccesstheimagefilepathandnameinsteadoftheimagefile,picturefilesstoredindisk.Ifapicturestoredinthepathspecialwillbedisplayed,wecanusepicturecontrolordatawindowtorealize.Picturesarenotstoredinthedatabase,thedatabasewillnotturnbigandthepicturewillbedisplayedmorequickly.

1）Picturecontrolmode

Placeapicturecontrolinthewindow,displaypicturesstoredinthepathofpictureasrunningwindow.Thescriptofwindowinitsopeneventisasfollowing:

stringls_path//storagepath

selecttpljinto:

ls_pathfromtpwheretpbh='20090310';//fieldtpljsavestoragepathofthepicturep_1.picturename=ls_path//displaypicture

2）Datawindowmode

Selectallthefieldsfromtpbtableandcreatefreeformstyledatawindowobject.Selectdisplayaspicturepropertyoftpljfieldingeneraltabofdatawindow,whichisthekeytobeabletoshowthepicture.Createadatawindowobjectandbindingadatawindowcontrol,inopeneventofthewindowenterthescriptcodeisasfollowing:

dw_1.settransobject（sqlca）

dw_1.retrieve（）

Thus,tpljfieldwillshowthepictureratherthanthestoragepathasprogramrunning.

B.AccessPicturesbyUseofTableField

Inrealapplication,thepictureisoftennecessarystoredinthedatabasetodeal.Asforthepicturetypesofdataarenotdirectlyoperateinthebackgrounddatabase,onlyintheprocedureadoptedbythecorrespondingcommandtoachieve.Backgrounddatabaseadaptiveserveranywheredatabaseasanexample,fieldtypestoredpicturesmustbedefinedaslongbinaryorlongvarchar,thatis,blobdata,andthefieldofnullvalueofpropertymustbesettoyes,otherwisethepicturewillnotbeabletostoreinthedatabase.

ThedirectuseofSQLstatementsintheupdateandselectcommandsareunabletooperateblobdatastoredindatabase.PowerBuilderprovidestwooperationcommandsforblobdata:

selectblobstatementandupdateblobstatement.

Selectblobstatementisusedtoreadblobdataanditsbasicsyntaxruleis:

selectblobrestofselectstatement{usingtransactionobject};

Updateblobstatementisusedtoupdateblobdataanditsbasicsyntaxruleis:

updateblobtablename

setblobcolumn=blobvariable

restofselectstatement{usingtransactionobject};

Now,entryinformationtostudentsasanexampletoshowhowtheblobdatastoredinthedatabase.

1）Createfreeformstyledatawindowobject,selectallthedatafieldsofstudentinformationtable.Note,blobfieldcan'tbeshown,ofcourse,itcan'tbeselected.

2）Insertthedatabasebinary/textlargeobjectcontrolintothedatawindowandsetthecorrespondingoptionsparameters,asshowninfigure1.

Figure1.BlobFieldPropertySettings

3）Insertacommandbuttoncontrolinthedatawindow,settextpropertyasselectpictureandsetnamepropertyascb_select,adjustthedatawindowlayout,finishthedatawindowobjectcreation.

4）Createanewwindowobject,placeadatawindowcontrolandbindthejustcreateddatawindowobject.Placethreebuttonscontrol,onepicturecontrolandoneolecontrol,setvisiblepropertyofolecontroltofalse.Apicturecontrolandanolecontrolwereplacedsimultaneouslybecauseolecontrolcan'tdisplayJPG,GIFandothertypeofpicture,butdisplayfilepathonly.Thoughpicturecontrolcandisplaythesetypesofpicture,butcan'tgetthepicturestorage.So,usingpicturecontroltoshowpictureandolecontroltostorepicture.

5）Themainscriptofdatawindowinitsclickedeventisasfollowing:

longll_row

ifdwo.name="cb_select"then

ll_row=dw_1.getrow（）

stringfilepath,filename//storagepathandnameofthepicture