1.1   Pseudocode

All examples will use a pseudocode that is consistent with the language independent API reference. Each line is a statement. For object attributes and methods we use the dot, '.', operator. Creation and deletion of objects will be indicated by 'new' and 'del' keywords. Other than that, the pseudocode looks a lot like Python.

3.1   Creating imageObj from a mapObj

The mapObj class has two methods that return instances of imageObj: 'draw', and 'prepareImage'. The first returns a full-fledged map image just as one would obtain from the mapserv CGI program:

test_map = mapscript.mapObj('tests/test.map')
map_image = test_map.draw()

A properly sized and formatted blank image, without any layers, symbols, or labels, will be generated by 'prepareImage':

blank_image = test_map.prepareImage()

3.2   Creating a new imageObj

The imageObj class constructor creates new instances without need of a map:

format = mapscript.outputFormatObj('GD/JPEG')
image = mapscript.imageObj(300, 200, format)   # 300 wide, 200 high JPEG

and can even initialize from a file on disk:

# First three args are overriden by attributes of the disk image file
disk_image = mapscript.imageObj(-1, -1, NULL, 'tests/test.png')

4.1   Creating files on disk

Imagery is saved to disk by using the 'save' method. By accessing the 'extension' attribute of an image's format, the proper file extension can be used without making any assumptions:

filename = 'test.' + map_image.format.extension
map_image.save(filename)

If the image is using a GDAL/GTiff-based format, a GeoTIFF file can be created on disk by adding a mapObj as a second optional argument to 'save':

map_image.save(filename, test_map)

4.2   Direct Output

An image can be dumped to an open filehandle using the 'getBytes' method which is preferred to 'write' for MapServer 4.5/6. By default, the filehandle is 'stdout':

# Send an image to a web browser
print 'Content-type: ' + map_image.format.mimetype + '\n'
print map_image.getBytes()

This method is not fully functional for all SWIG mapscript languages. See the API Reference (mapscript.txt) for details. The 'getBytes' method is new in 4.5.