[reportlab-users] Can a pagetemplate modify its frames?

[Robin Becker]

Roberto Alsina wrote:

> On Thursday 28 August 2008 11:54:58 Roberto Alsina wrote:

>> I am trying to implement a "smart page" PageTemplate which does things like

>> adjust margins and show/hide headers and footers depending on the content.

>>

>> Can I modify self.frames from a PageTemplate?

>>

>> I tried this to implement a "gutter margin" with no visible effect:

>>

>>     def beforePage(self,canv,doc):

> 

> Make that beforeDrawPage (BTW, the manual is wrong here ;-)

> 

>>         print self.frames[0].__dict__

>>

>>         # Adjust gutter margins

>>         if doc.page%2: #Odd page

>>             gm=self.gm

>>         else: # Even page

>>             gm=-self.gm

>>

>>         print gm

>>

>>         for f in self.frames:

>>             f._x+=gm

>>             f._x1+=gm

>>             f._x2+=gm

>>

>> The values change but the frame doesn't move :-)

> 


you're messing with bad stuff here. These classes were created before python had 
properties etc etc so I think you'll need either to overwrite the frame with a 
new instance or to adjust the external properties x1, y1 etc etc and force the 
geometry to recalculate. If you do

f.a=z where a is one of ('x1', 'y1', 'width', 'height', 'leftPadding', 
'bottomPadding', 'rightPadding', 'topPadding') then the underlying _a variable 
is actually set and the frame recalculates its geometry.

According to Andy the right way to do this sort of odd/even page stuff is to use 
  a pagetemplate cycle basically need to use

NextPageTemplate(['left','right'])
PageBreak()

in the story and then we iterate left & right templates.
-- 
Robin Becker