[reportlab-users] newbie questions

Robin Becker reportlab-users@reportlab.com
Fri, 11 Jun 2004 20:01:47 +0100

Randall Smith wrote:
> I have a few newbie questions.
> 1. When using document and page templates, what's the best way to 
> include header/footer information?
Header and footer stuff is best done by providing each template with an 
onPage attribute. This gets called like

Note that this is not a method of the page template, but an ordinary 
function. You can also override the methods template.beforeDrawPage, 
template.afterDrawPage which are called with canvas & document as 
arguments. In side these methods you can do what you want to the canvas. 
Note that these are considered low level so you need to wrap stuff in 
canvas.save/restore to avoid unwanted side effects.

> 2. I want a flowable to draw a horizontal line that spans the width of 
> the page.  The draw method is something like this:
> def draw(self):
>     self.canv.setLineWidth(line_thickness)
>     self.canv.line(0, .5 * line_thickness, ?, .5 * line_thickness)
> Notice the ?
> How can I know how long to draw the line?

Before each flowable is drawn a wrap method

signature wrap(self, availWidth, availHeight)

is called on the flowable. You are supposed to return the amount of 
space needed by the flowable. So for your line thing you could use

	def wrap(self,availWidth, availHeight):
		self._width = availWidth
		self._height = line_thickness
		return self._width, self._height

then you can refer to the _width attribute when draw gets called.

Robin Becker