[reportlab-users] Embedding Platypus Story in Canvas

[Tim Roberts]

Rich Shepard wrote:

> On Tue, 6 Nov 2007, Tim Roberts wrote:

>

>> You have two choices.

>   ...

>> 2. You can derive your own class from SimpleDocTemplate, and override

>> _startBuild to use the canvas you pass in.

>

>   I'm really in a hole. Did this but still no joy. Here's the class:

>

>     class MyTemplate(SimpleDocTemplate):

>       _invalidInitArgs = ('pageTemplates',)

>

>       myCanvas = canvas.Canvas('input_variables.pdf', pagesize=LETTER)

>

>       def _startBuild(self, filename='input_variables.pdf',

> canvasmaker=myCanvas):

>         self._calc()

>         self.canv = canvasmaker(filename or self.filename,

>                                 pagesize=self.pagesize,

>                                 invariant=self.invariant,

>                                 pageCompression=self.pageCompression)

>         if self._onPage:

>           self.canv.setPageCallBack(self._onPage)

>         self.handle_documentBegin()

>

>   And in class ProjectReports() I assign

>

>     pg = MyTemplate.myCanvas

>

> so all additional references to pg become self.pg. No python errors, but

> still only a one-page report.


Create the canvas outside of the class, and pass it in.  So:

    class MyTemplate( SimpleDocTemplate ):
      def _startBuild( self, filename, canvas ):
        self._calc()
        self.canv = canvas
        self._doSave = 0
        if self._onPage:
          senf.canv.setPageCallBack(self._onPage)
        self.handle_documentBegin()

Then, when you call it, pass in the canvas:

    myCanvas = canvas.Canvas( 'input_variables.pdf', pagesize=LETTER )
    doc = MyTemplate( None, canvas )

However, if you don't need to override anything, why don't you just let
the template create the canvas and pull it out later?

-- 
Tim Roberts, timr at probo.com
Providenza & Boekelheide, Inc.