Anthony

As you requested. Hopefully it is clear enough...

Usage
1. Create a separate AutoColumnSizer for each column on each sheet.
2. For each cell you add, call AutoColumnSizer.isNotificationRequired.
3. If that returns true, call AutoColumnSizer.notifyCellValue.
...
4. After all cells are added, call AutoColumnSizer.getWidth.
5. Multiply the result by a magic number (I use 48) and pass that to 
HSSFSheet.setColumnWidth.

You can see from reading the TODOs there are unresolved issues with this 
approach.

Take a float cell with value 100000.
At the moment I check the width of "100000". But depending on the style, the 
*displayed* value might be considerably wider, e.g. "100,000.00". So you 
basically ought to replicate Excel style handling too...

So I don't think this will ever be a good general purpose solution. But it's 
good enough for us.

Cheers
Iain


-----Original Message-----
From: Anthony Andrews [mailto:[EMAIL PROTECTED] 
Sent: 19 January 2006 14:08
To: POI Users List
Subject: RE: [poi] Column --> Autofit selection


This is well off topic so I apologise but I was  very interested to hear that 
Ian. In the past, I have done loads - far  too much really - printing using 
Java; that is where I first ran into  the FontMetrics class. Never noticed that 
discrepancy you mentioned  with regard to different fonts. Must be that 
checking line lengths is  far less critical than column widths. Must go back 
and have another  look when I get the chance.
  
  Is it OK if I have a look at your code as well if you post it for Thomas?

[EMAIL PROTECTED] wrote:  Thomas,

I have actually written the code to do it using FontMetrics as Antony suggested.

The  performance hit is around 1 second on our hardware, I have a simple  
sampling algorithm so I only check cell widths on a sample of the rows  (I 
check around 400 rows for a 65,536 row spreadsheet).

However  the FontMetrics widths don't exactly match with Excel widths, there is 
 a certain difference. A multiplication factor that makes the Excel  columns 
look perfect for Arial 10pt, is wrong for Arial 18pt bold. I  haven't bothered 
trying to solve this problem as we only ever use Arial  10.

Let me know if you want this code, I will try and extract it.

Iain



-----Original Message-----
From: Anthony Andrews [mailto:[EMAIL PROTECTED] 
Sent: 19 January 2006 09:29
To: POI Users List
Subject: Re: [poi] Column --> Autofit selection


Hello Thomas,
  
  Sorry to say there is not an easier way than this. It would be nice to  have 
a method that replicates what Excel does when you work  interactively with it 
or one that mimics the applications response when  you click on one of the 
row/column dividers but there is nothing like  this as far as I know.
  
  [EMAIL PROTECTED] wrote:  Hello Christian, Hi Anthony,

many thanks for your help.
Actually I was hoping there will be a "cheaper" way to do it ;-) So I will go 
the hard way, if necessary.

Thanks,
Thomas




There  is another way if you are wiling to go to the trouble. It is possible  
using the FontMetrics class to discover the length of a String with  some 
accuracy. This technique will also compensate for different  fonts/font sizes 
and could overcome the problem Christian notes under  point a) in his reply. Be 
prepared for a performance hit if you use  this technique as you will be 
creating and destroying quite a number of  different objects.

  Aside from this, I would do EXACTLY what Christian advises.

Christian Gosch  wrote:  We do the hard work way:

We  just track every value we enter resp. its length as a String and hold  an 
array/list with an entry for the max. length (that is char count) of  every 
column. After filling of the sheet is complete, we go through the  columns and 
set every column width according to its matching measure.  For this we use a 
factor based on advice by POI, currently 256. This  cuts longer texts (hides 
the last chars), but works for usual cases.

In fact this is a bit ugly, since...
(a)  the calculated length does not really handle cases like "iiiii" vs.  
"WWWWW" with proportional fonts, witch would in turn require to  calculate the 
"real" (optical) width of the textual content based on  font metrics data :-( 
But Excel is not very good in doing this job also  :-)
(b) *of course* it would be fine to have just an option  associated with the 
column that says "auto-fit". But as far as I can  see, Excel does simply not 
provide that: In fact it seems that Excel  calculates the optimal width just on 
(dialogue user) demand and sets  the actual result of this computation as new 
column width. :-(

hth,
--cg

On Wednesday, January 18, 2006 4:14 PM [GMT+1=CET], [EMAIL PROTECTED]  wrote:

> Hello,
>
> I try to define the layout of columns in POI.
> Is there a way in POI to set the column to the optimal width? In Excel
> you can achieve this by hand: Format-->Column-->Autofit Selection. 
> Does POI provide a  method doing the same?
>
> What I know is how to set a default width:
> ###
> HSSFSheet sheet = wb.createSheet("Test");
> ....
> sheet.setDefaultColumnWidth((short)20);
> ###
>
> Is there a smarter way?
> Many thanks in advanced!
> Thomas
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: [EMAIL PROTECTED]
> Mailing List:     http://jakarta.apache.org/site/mail2.html#poi
> The Apache Jakarta Poi Project:  http://jakarta.apache.org/poi/

Regards,
--
Dipl.-Inform. Christian Gosch
Systems Development
inovex GmbH
Karlsruher Strasse 71
D-75179 Pforzheim
Tel.: +49 (0)72 31 - 31 91 - 85
Fax: +49 (0)72 31 - 31 91 - 91
mailto:[EMAIL PROTECTED]
http://www.inovex.de


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