"

 COPYRIGHT (c) 1989 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

"{ Package: 'stx:libwidg' }"

View subclass:#ListView

	instanceVariableNames:'list firstLineShown nFullLinesShown nLinesShown fgColor bgColor

		partialLines leftMargin topMargin textStartLeft textStartTop

		innerWidth tabPositions lineSpacing fontHeight fontAscent

		fontIsFixedWidth fontWidth autoScroll autoScrollBlock

		autoScrollDeltaT wordCheck includesNonStrings widthOfWidestLine

		listMsg viewOrigin listChannel backgroundAlreadyClearedColor

		scrollWhenUpdating scrollLocked'

	classVariableNames:'DefaultForegroundColor DefaultBackgroundColor DefaultTabPositions

		UserDefaultTabPositions DefaultLeftMargin DefaultTopMargin'

	poolDictionaries:''

	category:'Views-Text'

!

!ListView class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1989 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

!

documentation

"

    a View for (string-)lists.

    This class can only passively display collections of strings-

    selections, editing, cursors etc. must be done in subclasses.

    see SelectionInListView, TextView etc.

    This code currently handles only fixed-height fonts correctly -

    should be rewritten in some places ...

    It can only scroll by full lines vertically (i.e. setting firstLineShown to ~~ 1)

    which should be changed to have this behavior optionally for smooth scroll.

    The text is internally kept in the list instance variable, and is supposed to consist

    of a collection (Ordered- or StringCollection) of line entries.

    Typically, individual entries are either strings or nil (for empty lines).

    However, any object which supports the displayOn: and widthIn: protocol can be

    used - see MultipleColumnListEntry as an example.

    Therefore, ListView (and all subclasses) are prepared to handle non-string entries

    (especially: attributed Text).

    The internal version of the text has tabulators expanded to blanks - when text is exchanged

    with an external medium (i.e. reading/writing files), these are expanded/compressed assuming

    a tab-setting of 8. This is done independent of the users tab setting, which is used

    while the text is edited. Thus, even if the tab setting is multiple of 4's, tabs are

    written in multiples of 8 when the text is saved. Since this is the default on all ascii

    terminals and printers, this assures that the text looks correctly indented when finally printed.

    Notice:

    ListView is one of the oldest widget classes in the current system and

    definitely requires some rewrite:

    Due to historic reasons (ListView implemented scrolling before the general

    scrolling code in View was added), this one does scrolling different from all other

    views. The general scrolling code (in View) uses the transformation for transparent scrolling.

    Here, the transformation is not used, instead it is done again, by keeping the firstLineShown

    (i.e. vertical offset) and leftOffset (horizontal offset).

    The most annoying consequence of this is, that scrolling is done by lines here, 

    while its done in pixels in the View class. Thus, be careful, when changing things

    (better: dont touch it ;-)

    Also, all controller functionality is completely performed by the listView

    (and subclasses) itself. It is still possible, to define and set a specialized

    controller, though. I.e. if you like to change the input behavior, define

    a corresponding controller class and intersect the keyXXX/buttonXXX messages

    there.

    This will be totally rewritten ... so dont depend on the internals; especially the scrolling

    code will be totally removed here and the inherited functionality be used in the next version.

    [Instance variables:]

      list                <aCollection>           the text strings, a collection of lines.

						  Nils may be used for empty lines.

      firstLineShown      <Number>                the index of the 1st visible line (1 ..)

      leftOffset          <Number>                left offset for horizontal scroll

      nFullLinesShown     <Number>                the number of unclipped lines in visible area

						  (internal; updated on size changes)

      nLinesShown         <Number>                the number of lines in visible area, incl. partial

						  (internal; updated on size changes)

      fgColor             <Color>                 color to draw characters

      bgColor             <Color>                 the background

      partialLines        <Boolean>               allow last line to be partial displayed

      leftMargin          <Number>                margin at left in pixels

      topMargin           <Number>                margin at top in pixels

      textStartLeft       <Number>                margin + leftMargin (internal)

      textStartTop        <Number>                margin + topMargin (internal)

      innerWidth          <Number>                width - margins (internal)

      tabPositions        <aCollection>           tab stops (cols)

      fontHeight          <Number>                font height in pixels (internal)

      fontAscent          <Number>                font ascent in pixels (internal)

      fontIsFixed         <Boolean>               true if its a fixed font (internal)

      fontWidth           <Number>                width of space (internal)

      lineSpacing         <Number>                pixels between lines

      lastSearchPattern   <String>                last pattern for searching 

						  (kept to provide a default for next search)

      lastSearchIgnoredCase   <Boolean>           last search ignored case

						  (kept to provide a default for next search)

      wordCheck           <Block>                 rule used for check for word boundaries in word select

						  The default rule is to return true for alphaNumeric characters.

						  (can be changed to allow for underscore and other

						   characters to be treated as alphaCharacters)

      autoScrollBlock     <Block>                 block installed as timeoutBlock when doing an

						  autoScroll (internal)

      autoScrollDeltaT                            computed scroll time delta in seconds (internal)

      includesNonStrings                          cached flag if any non-strings are in list

      widthOfWidestLine                           cached width of widest line

      listMsg                                     if view has a model and listMsg is non-nil,

						  this is sent to the model to aquired a new contents

						  whenever a change of the aspect  (aspectMsg) occurs.

      viewOrigin                                  the current origin 

      backgroundAlreadyClearedColor               internal; speedup by avoiding

						  multiple fills when drawing

						  internal lines

      scrollWhenUpdating

				<Symbol>        defines how the view is scrolled if the

						model changes its value by some outside activity

						(i.e. not by user input).

						Can be one of:

						    #keep / nil     -> stay unchanged

						    #endOfText      -> scroll to the end

						    #beginOfText    -> scroll to the top

						The default is #beginOfText (i.e. scroll to top).

    [StyleSheet parameters:]

      textForegroundColor                         defaults to Black

      textBackgroundColor                         defaults to White

      textFont                                    defaults to defaultFont

      textTabPositions                            defaults to #(1 9 17 25 ...)

    [author:]

	Claus Gittinger

    [see also:]

	TextView EditTextView

"

!

examples 

"

    ListViews alone are rarely used - its mostly an abstract superclass

    for TextView, EditTextView and SelectionInListView.

    anyway, here are a few examples:

     basic simple setup:

      specifying textMargins (these have NOTHING to do with the viewInset):

      globally set the fg/bg colors:

      non-string (text) entries:

      generic non-string entries:

      (notice: ColoredListEntry is obsoleted by Text)

      using a model (default listMessage is aspectMessage):

      using a model with different aspects

      for two listViews:

"

! !

!ListView class methodsFor:'defaults'!

defaultTabPositions

    "return an array containing the styleSheets default tab positions"

    ^ DefaultTabPositions ? self tab8Positions

!

defaultTabPositions:aVector

    "set the array containing the styleSheets tab positions"

    DefaultTabPositions := aVector

    "

     self defaultTabPositions:(self tab4Positions)

    "

!

tab4Positions

    "return an array containing tab positions for 4-col tabs"

    ^ #(1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 

	85 89 93 97 101 105 109 113 114 121 125 129 133 137 141 145)

!

tab8Positions

    "return an array containing tab positions for 8-col tabs"

    ^ #(1 9 17 25 33 41 49 57 65 73 81 89 97 105 113 121 129 137 145)

!

updateStyleCache

    "extract values from the styleSheet and cache them in class variables"

    <resource: #style (#'text.foregroundColor' #'text.backgroundColor'

		       #'text.tabPositions'

		       #'text.font')>

    DefaultForegroundColor := StyleSheet colorAt:'text.foregroundColor' default:Black.

    DefaultBackgroundColor := StyleSheet colorAt:'text.backgroundColor' default:White.

    DefaultFont := StyleSheet fontAt:'text.font'.

    DefaultTabPositions := StyleSheet at:'text.tabPositions'.

    DefaultTabPositions isNil ifTrue:[DefaultTabPositions := self defaultTabPositions].

    DefaultLeftMargin := 0.5.

    DefaultTopMargin := 0.5.

    "Modified: 20.10.1997 / 15:05:30 / cg"

!

userDefaultTabPositions

    "return an array containing the users default tab positions"

    ^ UserDefaultTabPositions

!

userDefaultTabPositions:aVector

    "set the array containing the users tab positions"

    UserDefaultTabPositions := aVector

    "

     self userDefaultTabPositions:(self tab4Positions)

    "

! !

!ListView methodsFor:'accessing'!

innerHeight

    "return the number of pixels visible of the contents

     - redefined since ListView adds another margin to start the text

     somewhat to indented from the 3D border."

    ^ height - (2 * margin) - topMargin

!

wordCheckBlock:aBlock

    "set the word-check block - this block is called with a character argument,

     when the end/beginning of a word is searched.

     It should return true, if the character belongs to the word.

     The default block is set in #initialize, and returns true for alphanumeric

     (national) characters.

     Applications may change it to include underlines, dollars or other characters. 

     (a C/C++ editor would include underlines ...)"

    wordCheck := aBlock.

    "Modified: 22.5.1996 / 12:26:55 / cg"

! !

!ListView methodsFor:'accessing-behavior'!

scrollWhenUpdating

    "return the scroll behavior, when I get a new text 

     (via the model or the #contents/#list)

     Possible returnValues are:

        #keep / nil     -> no change

        #endOfText      -> scroll to the end

        #beginOfText    -> scroll to the top

     The default is #keep.

     This may be useful for fields which get new values assigned from

     the program (i.e. not from the user)"

    ^ scrollWhenUpdating

!

scrollWhenUpdating:aSymbolOrNil

    "define how to scroll, when I get a new text 

     (via the model or the #contents/#list)

     Allowed arguments are:

        #keep / nil     -> no change

        #endOfText      -> scroll to the end

        #beginOfText    -> scroll to the top

     The default is #keep.

     This may be useful for fields which get new values assigned from

     the program (i.e. not from the user)"

    scrollWhenUpdating := aSymbolOrNil

! !

!ListView methodsFor:'accessing-contents'!

add:aString

    "add a line and redisplay"