问题
I'm using XSL-FO to generate an account statement print out. The PDF is actually just a simple table with a simple header on every page. The difficulty is that I have to display transaction volumes per page, e.g.
Page 1
+------------------------------+-----------+-----------+---------------------+
| Text | Credit | Debit | Balance |
+------------------------------+-----------+-----------+---------------------+
| Previous month | | | (*1) 1000 |
| abc | 1000 | | 2000 |
| abc | | 500 | 1500 |
| abc | | 200 | 1300 |
| ... | | | |
| Carry over | (*2) 1000 | (*3) 700 | (*4) 1300 |
+------------------------------+-----------+-----------+---------------------+
Page 2
+------------------------------+-----------+-----------+---------------------+
| Text | Credit | Debit | Balance |
+------------------------------+-----------+-----------+---------------------+
| Previous page | (*2) 1000 | (*3) 700 | (*4) 1300 |
| abc | 1000 | | 2300 |
| abc | | 500 | 1800 |
| abc | | 200 | 1600 |
| ... | | | |
| Carry over | (*2) 2000 | (*3) 1400 | (*4) 1600 |
+------------------------------+-----------+-----------+---------------------+
Here are some explanations:
- This is the previous month's balance. It's pre-calculated and well-known as an XSL variable. No problem with that, that's a regular header (only on the first page)
- This value is calculated on a per-page basis. It sums up all credit amounts on the same page. I can't calculate that myself, as I don't know when XSL-FO will do the page break. So I imagine XSL-FO must do the calculation for me. The sum at the bottom of a page is the same as the value at the top of the subsequent page.
- This value is the same as 2, only for debit amounts.
- This value is just the last transaction's balance at the bottom of a page. That value is repeated at the top of the next page.
How can I do these calculations with XSL-FO?
See also this related question: How to display one or the other information depending on the page number in XSL-FO?
回答1:
Try "table markers": http://www.w3.org/TR/xsl/#fo_retrieve-table-marker.
In XSLT for each row inject a marker with the sum. Then let the engine select a marker to substitute for the fo:retrieve-table-marker in table header or footer. The idea is that proper marker will be selected at rendering time depending on the marker's position on the page and @retrieve-position and @retrieve-boundary on the fo:retrieve-table-marker.
回答2:
Unfortunately, fop doesn't implement <fo:retrieve-table-marker/> from what I have found out. Instead, this solution here worked for me:
How to display one or the other information depending on the page number in XSL-FO?
It involves creating a separate table outside of the <fo:flow/> that displays the table header using <fo:retrieve-marker/> elements.
来源：https://stackoverflow.com/questions/7931266/how-can-i-sum-up-some-values-per-page-in-a-table-in-xsl-fo