81 lines
2.6 KiB
Python
81 lines
2.6 KiB
Python
#Copyright ReportLab Europe Ltd. 2000-2004
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#see license.txt for license details
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#history http://www.reportlab.co.uk/cgi-bin/viewcvs.cgi/public/reportlab/trunk/reportlab/docs/userguide/ch7_custom.py
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from reportlab.tools.docco.rl_doc_utils import *
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heading1("Writing your own $Flowable$ Objects")
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disc("""
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Flowables are intended to be an open standard for creating
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reusable report content, and you can easily create your
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own objects. We hope that over time we will build up
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a library of contributions, giving reportlab users a
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rich selection of charts, graphics and other "report
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widgets" they can use in their own reports. This section
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shows you how to create your own flowables.""")
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todo("""we should put the Figure class in the
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standard library, as it is a very useful base.""")
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heading2("A very simple $Flowable$")
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disc("""
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Recall the $hand$ function from the $pdfgen$ section of this user guide which
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generated a drawing of a hand as a closed figure composed from Bezier curves.
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""")
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illust(examples.hand, "a hand")
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disc("""
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To embed this or any other drawing in a Platypus flowable we must define a
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subclass of $Flowable$
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with at least a $wrap$ method and a $draw$ method.
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""")
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eg(examples.testhandannotation)
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disc("""
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The $wrap$ method must provide the size of the drawing -- it is used by
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the Platypus mainloop to decide whether this element fits in the space remaining
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on the current frame. The $draw$ method performs the drawing of the object after
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the Platypus mainloop has translated the $(0,0)$ origin to an appropriate location
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in an appropriate frame.
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""")
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disc("""
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Below are some example uses of the $HandAnnotation$ flowable.
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""")
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from reportlab.lib.colors import blue, pink, yellow, cyan, brown
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from reportlab.lib.units import inch
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handnote()
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disc("""The default.""")
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handnote(size=inch)
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disc("""Just one inch high.""")
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handnote(xoffset=3*inch, size=inch, strokecolor=blue, fillcolor=cyan)
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disc("""One inch high and shifted to the left with blue and cyan.""")
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heading2("Modifying a Built in $Flowable$")
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disc("""To modify an existing flowable, you should create a derived class
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and override the methods you need to change to get the desired behaviour""")
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disc("""As an example to create a rotated image you need to override the wrap
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and draw methods of the existing Image class""")
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import os
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from reportlab.platypus import *
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I = '../images/replogo.gif'
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EmbeddedCode("""
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class RotatedImage(Image):
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def wrap(self,availWidth,availHeight):
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h, w = Image.wrap(self,availHeight,availWidth)
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return w, h
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def draw(self):
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self.canv.rotate(90)
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Image.draw(self)
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I = RotatedImage('%s')
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I.hAlign = 'CENTER'
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""" % I,'I') |