Re: NSTableColumn : Help required

FROM : Fritz Anderson
DATE : Wed Nov 20 22:50:58 2002

This involves more steps than can be jotted down in detail into a
single email, but here are the considerations...

I assume you have the full-length string readily available. You give
the example of a currency amount, but I'm going to assume you can get
that from your data source, or by way of an NSNumberFormatter.

I also assume that the character that didn't come through in your
message was the horizontal-ellipsis character (...).

In your implementation of tableView:objectValueForTableColumn:row:, for
the column in question, you can pass -width to the column to get its
width. You then define this method:

@interface NSString (truncation)
- (NSString *) truncatedWithEllipsisAtEnd: (float) width;
@end

Its logic is:

Obtain the string-drawing attributes for the cell and put them in an
NSDictionary.
If [self sizeWithAttributes: attributeDictionary].width <= width
   return [[self retain] autorelease];

Otherwise, set up a binary search:
lowBound, highBound, middle observe integer math.
lowBound = 1, highBound = [self length] -1

let Subst(n) be equivalent to
    [[self substringToIndex: n] stringByAppendingString:
horizontalEllipsis]
Verify that Subst(lowBound) is narrower than width (exception, or maybe
return horizontal ellipsis, if not)
and that Subst(highBound) is wider than width (return Subst(highBound)
if not)

while lowBound < highBound - 1
   middle = (lowBound + highBound) / 2
   if Subst(middle) narrower than width
       lowBound = middle
   else if Subst(middle) is wider than width
       highBound = middle
   else
       return Subst(middle)
return Subst(lowBound)

Or: You could look at the OmniFoundation framework, which I remember
has ellipsis-truncation (both end and middle) methods, though I swear I
didn't lift them here. (For one thing, I'm pretty sure my notation for
Subst() is killingly inefficient, or could be made less so with a local
autorelease pool.)

   -- F

On Sunday, November 17, 2002, at 07:56  AM, Rakesh Pandey wrote:

> Hi All,
>
> I have a table to display a report. I don't want to make the columns
> of this
> table Autoresizable, rather I want to show a '
> ' as the last character when
> a cell has to show a string longer than its width. When the column is
> resized the display value should appear properly.
>
> For example : See the cell has to show $20000 and its width is
> sufficinet
> enough to show just $200 the I want to display $20
>  no inform the users to
> resize the column to see the entire text. If the user  resizez the
> column
> and still it can't show the entire string the '
> ' should appear.
>
> If any one has already done it, please help me out.
>
> Thanks in advance
> Rakesh
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