Python Appendix

Release:	4.4
Revision:	1.9
Date:	2004-11-14
Author:	Sean Gillies
Contact:	sgillies@frii.com

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Introduction
=============================================================================

The Python mapscript module contains some class extension methods that have not yet been implemented for other languages.

=============================================================================
Classes
=============================================================================

References to sections below will be added here as the documentation grows.

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imageObj
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The Python Imaging Library, http://www.pythonware.com/products/pil/, is an indispensible tool for image manipulation. The extensions to imageObj are all geared towards better integration of PIL in mapscript applications.

imageObj Methods
----------------

imageObj( PyObject arg1, PyObject arg2 [, PyObject arg3 ] ) : imageObj_
Create a new instance which is either empty or read from a Python file-like object that refers to a GD format image.

The constructor has 2 different modes. In the blank image mode, arg1 and arg2 should be the desired width and height in pixels, and the optional arg3 should be either an instance of outputFormatObj or a GD driver name as a shortcut to a format. In the image file mode, arg1 should be a filename or a Python file or file-like object. If the file-like object does not have a "seek" attribute (such as a urllib resource handle), then a GD driver name *must* be provided as arg2.

Here's an example of creating a 320 pixel wide by 240 pixel high JPEG using the constructor's blank image mode::

image = mapscript.imageObj(320, 240, 'GD/JPEG')

In image file mode, interesting values of *arg1* to try are instances of *StringIO*::

s = StringIO()
pil_image.save(s) # Save an image manipulated with PIL
ms_image = imageObj(s)

Or the file-like object returned from *urlopen*

::

url = urllib.urlopen('http://mapserver.gis.umn.edu/bugs/ant.jpg')
ms_image = imageObj(url, 'GD/JPEG')


write( [ PyObject file ] ) : void
Write image data to a Python file-like object. Default is stdout.

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pointObj
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pointObj Methods
----------------

__str__() : string
Return a string formatted like

::

{ 'x': %f , 'y': %f }


with the coordinate values substituted appropriately. Usage example:

::

>>> p = mapscript.pointObj(1, 1)
>>> str(p)
{ 'x': 1.000000 , 'y': 1.000000 }


Note that the return value can be conveniently eval'd into a Python dictionary:

::

>>> p_dict = eval(str(p))
>>> p_dict['x']
1.000000


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rectObj
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rectObj Methods
---------------

__contains__( pointObj point ) : boolean
Returns True if *point* is inside the rectangle, otherwise returns False.

::

>>> r = mapscript.rectObj(0, 0, 1, 1)
>>> p = mapscript.pointObj(2, 0) # outside
>>> p in r
False
>>> p not in r
True


__str__() : string
Return a string formatted like

::

{ 'minx': %f , 'miny': %f , 'maxx': %f , 'maxy': %f }


with the bounding values substituted appropriately. Usage example:

::

>>> r = mapscript.rectObj(0, 0, 1, 1)
>>> str(r)
{ 'minx': 0.000000 , 'miny': 0.000000 , 'maxx': 1.000000 , 'maxy': 1.000000 }


Note that the return value can be conveniently eval'd into a Python dictionary:

::

>>> r_dict = eval(str(r))
>>> r_dict['minx']
0.000000