[Biococoa-dev] Fwd: Re : Strange Selection Behavior when using a custom NSTextContainer

[Alexander Griekspoor]

First I thought it was my message which finally arrived on the cocoa- 
dev list, turns out someone else has exactly the same problem as we do!
See the mail below, perhaps it helps solving this nasty bug...
Alex

Begin forwarded message:

> From: Alexander Griekspoor <a.griekspoor at nki.nl>
> Date: 27 maart 2006 13:01:32 GMT+02:00
> To: ernfrid at gmail.com
> Subject: Re : Strange Selection Behavior when using a custom  
> NSTextContainer
>
> Hi David,
>
> I have exactly the same problem, well slightly different, but at  
> first I thought your message was mine. I am trying to post the  
> message below to apple's cocoa-dev but it seems they are offline.  
> Here is a copy,
> perhaps we can together find out what goes wrong... If you have  
> found the solution already I would love to hear. Many thanks!
> Cheers,
> Alex
> PS. I'm not a member of Omni's mailinglist, could you post my  
> message for the record and also for others to help us out?
>
>
> *******
> Weird bug with selection in Textview with custom textcontainer
>
>
> Hi all,
>
> I ran in this weird bug and you guys are my last resort..
> For a new DNA analysis program I subclassed Koen van der Drift's  
> excellent NSTextView linenumbering variant and modified the  
> textcontainer such that it automagically adds spaces between every  
> 10th character. I did this by overriding in NSTextContainer (see  
> below).
>
> This works beautifully except for this single strange behaviour  
> where text is not selected if
> A) there are more than 10 characters (is one column) present
> B there's not more than 1 line of text.
>
> Trying to select the first 10 characters is not possible and a  
> reverse selection started at for instance char 20 back will stop  
> always at character 11. If the textview does not contain more than  
> 9 characters selection goes fine in the first column! So does it  
> when the textview contains more than one line of text!
>
> In other words, I cannot select the 10 characters in the first  
> column for some reason.
> I've illustrated the problem in this screenshot: http:// 
> www.mekentosj.com/temporary/textview_problem.jpg
>
> Any solution / clue where to start looking would be enormously  
> appreciated. Last bug standing before a release...
> Cheers,
> Alex
>
> - (NSRect)lineFragmentRectForProposedRect:(NSRect)proposedRect
>         sweepDirection:(NSLineSweepDirection)sweepDirection
>         movementDirection:(NSLineMovementDirection)movementDirection
>         remainingRect:(NSRect *)remainingRect
> {
> 	// create space for the linenumber margin
> 	if(proposedRect.origin.x <= 0.0)
> 		proposedRect.origin.x = kLEFT_MARGIN_WIDTH;
> 	
> 	// set the width of a column of text
> 	proposedRect.size.width = columnWidth;
> 	
> 	// make sure we nicely break after a full column
>     if (proposedRect.origin.x + 2 * columnWidth - 20.0 >= [self  
> containerSize].width) *remainingRect = NSZeroRect;
>     else {
>         remainingRect->origin.x = proposedRect.origin.x +  
> columnWidth - 10.0;
>         remainingRect->origin.y = proposedRect.origin.y;
>         remainingRect->size.width = [self containerSize].width -  
> proposedRect.origin.x  + columnWidth - 10.0;
>         remainingRect->size.height = proposedRect.size.height;
>     }
> 	
>     return proposedRect;
> }
>
>
>
>
>
> I'm using a custom NSTextContainer which breaks each line of the text
> view into columns of ten characters. I noticed that when there is only
> one line in the container, but there is text displayed outside of the
> first column, clicking in the that first column moves the cursor to
> the beginning of the second column instead of to its appropriate
> insertion point in the first column. I can move the cursor using the
> arrow keys into the first column, but even if the cursor is in the
> first column, clicking on that column sends the cursor back to
> beginning of the second column. If, however, there is only text in the
> first column or there is more than one line, clicking in the first
> column results in normal positioning of the cursor. I'm stumped. I
> played around with overriding containsPoint: and clicks in the first
> column were returned as being part of the container as they should be.
> I also used a subclass of NSTextView to check what NSTextView was
> returning for the selection function and found it was returning the
> incorrect insertion point. If I comment out my
> lineFragmentRectForProposedRect function then there is no problem with
> moving the cursor back to the first ten characters with the mouse. I
> should also mention I set the line fragment padding to zero and
> changing this has no effect on this behavior. Here is the code I'm
> using. columnWidth is the length of each column and gapWidth is the
> space between each column. Anyone have any ideas about what I'm doing
> wrong? I apologize for the long post but I believe it was necessary.
>
> Thanks
>
> David Larson
>
> - (NSRect)lineFragmentRectForProposedRect:(NSRect)proposedRect
> sweepDirection:(NSLineSweepDirection)sweepDirection
> movementDirection:(NSLineMovementDirection)movementDirection
> remainingRect:(NSRect *)remainingRect
> {
> 	if((sweepDirection != NSLineSweepRight) ||( movementDirection !=
> NSLineMovesDown)) {
> 		//check to make sure standard linesweep and movement direction  
> are correct
> 		return NSZeroRect;
> 	}
> 	else {
> 		//this code grabbed off of the CocoaBuilder webarchives from a Marco
> Binder post. Minor modifications to include gap size were included
> 		//Also modified the code to force a new line when the edge of the
> container is reached
> 		//Comments are mine
> 		
> 		//set the width to the column width
> 		//note that this assumes that the rect starts at the beginning of  
> a column
> 		
> 		proposedRect.size.width = columnWidth;
> 		
> 		if (proposedRect.origin.x+columnWidth >= [self  
> containerSize].width) {
> 			proposedRect.origin.x = 0; //if we can't fit the complete rect into
> the rest of the line, reset the line manually
> 			proposedRect.origin.y += proposedRect.size.height;
> 		}
> 		
> 		remainingRect->origin.x =
> proposedRect.origin.x+columnWidth+gapWidth; //move remaining rect
> origin to the next column start
> 		remainingRect->origin.y = proposedRect.origin.y;
> 		remainingRect->size.width = [self containerSize].width -
> proposedRect.origin.x - columnWidth-gapWidth; //size equals remaining
> screen space minus the column and gap
> 		remainingRect->size.height = proposedRect.size.height;
> 	}
> 	
> 	return proposedRect;
> }
>
> ***********************************
> Mek (Alexander Griekspoor)
>      MekenTosj.com
> Web: http://www.mekentosj.com
> Mail:  mek at mekentosj.com
> ***********************************
>
>

*********************************************************
                     ** Alexander Griekspoor **
*********************************************************
              The Netherlands Cancer Institute
              Department of Tumorbiology (H4)
         Plesmanlaan 121, 1066 CX, Amsterdam
                    Tel:  + 31 20 - 512 2023
                    Fax:  + 31 20 - 512 2029
                   AIM: mekentosj at mac.com
                    E-mail: a.griekspoor at nki.nl
                Web: http://www.mekentosj.com

     Claiming that the Macintosh is inferior to Windows
     because most people use Windows, is like saying
     that all other restaurants serve food that is
     inferior to McDonalds

*********************************************************

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