[reportlab-users] Reportlab performance

[Andy Robinson]

On 12 May 2010 14:55, Henning von Bargen <H.vonBargen at t-p.com> wrote:

> The idea is that you tell ReportLab in advance that you expect

> the TOC needs N pages (you can compute that in your special case,

> since you need one TOC row per article).



I have done some experiments and am checking in a small update now...

(a) platypus/doctemplate.py:  multibuild returns the number of passes,
rather than None.

(a) tests/test_platypus_toc.py now has a test demonstrating
'preloading' the table of contents, and asserting that it cuts the
number of passes from 3 to 2 for a document with a TOC longer than one
page..


If you 'preload' the TOC wth the correct section headings, you can get
down from 3 to 2 passes.
1 pass is not easy.  I don't know think it can be done with this
TableOfContents widget.  It
would need lazy drawing of forms.    Here's how to 'preload' it...

        toc = tableofcontents.TableOfContents()
        toc.levelStyles = [tocLevelStyle]   #need at least one style
        tocEntries = []
        for i in range(chapters):
            #add tuple of (level, text, pageNum=0, key=None)
            tocEntries.append((0, 'This is chapter %d' % i, 0, None))
        toc.addEntries(tocEntries)


Leszek, the time will definitely be spent inside multibuild, because
that's the outer loop!


Best Regards,

-- 
Andy Robinson
CEO/Chief Architect
ReportLab Europe Ltd.
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Tel +44-20-8545-1570