[reportlab-users] Page 1 of 3

[Robin Becker]

Juha Tuomala wrote:

> 

> 

> On Friday 26 January 2007 19:55, Robin Becker wrote:

>> The onPageEnd stuff allows you to use canvas level primitives to decorate the 

>> page. Assume you have a form called pageTotal then your page decorator does 

>> something like

>>

>> canvas.doForm('pageTotal')

>>

>> at the appropriate place on the page. Note that the form need not be defined 

>> when you reference it.

>>

>> At the end of the document build you need to set up the form using more canvas 

>> level operations.

>>

>> canvas.beginForm('pageTotal')

>> canvas.saveState()

>>

>> ......

>> canvas.drawString(x,y,str(nPages))

>> canvas.restoreState()

>> canvas.endForm()

> 

> 

> I've not been playing with forms yet, so is this 

> also possible with platypus+flowables?

> 

> I've laid out my pages with build parameters onFirstPage

> and onLaterPages.

>  

> 

> Tuju

> 


Yes you can reference the form in those functions. The hard part is knowing 
which is the 'last' page so you can define the form. A trick will allow you to 
do that though. Add an afterPage method to your document class that knows when 
the story is done.


Suppose your class is currently called DocA then either add an afterPage to it 
directly or derive another class from it and add the after page to that class.

class DocB(DocA):
     def afterPage(self):
         if hasattr(self,'_theEndAtLast'):
             #the last flowable has been drawn
             self.canv.beginForm('pageTotal')
             canvas.beginForm('pageTotal')
             canvas.saveState()
             canvas.drawString(x,y,str(self.page))
             canvas.restoreState()
             canvas.endForm()
         DocA.afterPage(self) #call the super method


The trick is to add a special flowable to your story that sets the attribute 
'_theEndAtLast' onto the document eg

class ThisIsTheEnd(ActionFlowable):
     def apply(self,doc):
         doc._theEndAtLast = 1

right at the end of your story creation

story.append(ThisIsTheEnd())


then when that flowable is processed the story is done and the doctemplate 
framework will eventually call afterPage so the form gets defined.
-- 
Robin Becker