resending to make it appear in the sqfixes page

> -----Mensaje original-----
> De:	Boris Gaertner [SMTP:Boris.Gaertner at gmx.net]
> Enviado el:	sábado 31 de mayo de 2003 11:46
> Para:	squeak-dev at lists.squeakfoundation.org
> Asunto:	[BUG] centered text is not properly displayed in MVC [with
> proposal for a fix]
> 
> This bug report refers to Squeak 3.4 latest update: #5170.
> The bug is also present in Squeak 3.3alpha latest update: #4981.
> It is not present in Squeak 3.2 alpha latest update: #4599
> 
> In an MVC project, centered text is sometimes not displayed centered.
> In Morphic this bug does not appear. 
> 
> I will first explain what works in Morphic:
> 1. In aMorphic project, open a workspace.
> 2. Type in a displayable character and select it.
> 3. In the context menu, select the item 'more...'
>    and (in the following menue) 'set alignment...'.
>    select the alignment 'centered'.
>    The character jumps into the middle of the
>    workspace. When you type in additional characters,
>    the text line is extended both to the left and to the right.
> 
>   After some typing, you see a beautifully centered
> multiline text. (When you resize the workspace to a
> small size, you will get this result with less typing  :-)  )
> 
> Now that you know that this works in Morphic, 
> create an MVC project and enter it.
> Open a workspace and do the same thing that you
> did with Morphic. You will see:
> 
> 1. The text is not displayed centered.
> 2. As soon as you have at least two lines, the
>     text will be displayed centered (but only from the
> second line) when you move the workspace on the screen.
> However the cursor rep. the current selection is displayed as
> for leftFlush text.
> 3. As soon as as you tpye in an additional character, the
>     the line that received that character is again displayed  left flush.
> 
> The first change set after #4599 that has significant chenges
> to the display machinery is
> #4614 (titled: 'TextAndFonts-ar' from  Dec 17, 2001). 
> Later followed:
> #4631 (MVCFixes-ar) without preamble,
> #4717 (CharBlockScannerFix-slg from Jan 10, 2002)
> #4723 (initMorphicOffsets-ls from Jan 19, 2002)
> #4727 (initLeftMArgin-ls from Jan 14, 2002)
> #4730 (FixUpdateGliches-di from Jan 30, 2002)
> 
> I think that the bug is simply a glitch that came in with
> #4614 and was never seen. (I work a lot with MVC but
> usually I feel no need to center text. Today I tested an
> editor and saw this problem.)
> 
> The point is - in my opinion - that in two methods
> (CharacterBlockScanner>>buildCharacterBlockIn: and
> !DisplayScanner displayLinesin:clippedBy:) the scanner
> is not completely initialized when the essential work is
> performed. In these methods the statement
> alignment ifNil:[textStyle alignment]
> is executed when the instance variable  alignment is still
> nil and this causes the use of the default. (Place a 'self beep.'
> into the block to verify this!) The assignment
> to 'alignment' is triggered in CharacterScanner>>setFont.
> In the presenece of an TextAlignment atribute, the
> 'att emphasiseScanner: self'  is sent to the TextAlignment
> instance which in turn calls  CharacterScanner>>setAlignment.
> 
> CharacterScanner>>setFont is called by CharacterScanner>>
> setStopConditions and I think that it is sufficient to send this
> method before the first call of
> leftMarginForDisplayForLine:alignment:
> to the paragraph.
> 
> 
> Attached you find a change set that is a proposal to fix this
> glitch. It is deliberately not labelled as a FIX. I want first to
> hear the opinions of  others on this mailing list. Afterall,
> a careless change to methods in CharacterScanner can
> easily ruin an image.
> 
> Greetings
> Boris
> 
> 
> 
> 
>  <<CenteredTextFix-Bg.zip>>  <<ATT758331.txt>> 
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