mapnik/tests/python_tests/render_test.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from nose.tools import *
import tempfile
import os, mapnik
from nose.tools import *
from utilities import execution_path

def setup():
    # All of the paths used are relative, if we run the tests
    # from another directory we need to chdir()
    os.chdir(execution_path('.'))


def test_simplest_render():
    m = mapnik.Map(256, 256)
    i = mapnik.Image(m.width, m.height)

    mapnik.render(m, i)

    s = i.tostring()

    eq_(s, 256 * 256 * '\x00\x00\x00\x00')

def test_render_image_to_string():
    i = mapnik.Image(256, 256)

    i.background = mapnik.Color('black')

    s = i.tostring()

    eq_(s, 256 * 256 * '\x00\x00\x00\xff')

    s = i.tostring('png')

def test_setting_alpha():
    w,h = 256,256
    im1 = mapnik.Image(w,h)
    # white, half transparent
    im1.background = mapnik.Color('rgba(255,255,255,.5)')

    # pure white
    im2 = mapnik.Image(w,h)
    im2.background = mapnik.Color('rgba(255,255,255,1)')
    im2.set_alpha(.5)

    eq_(len(im1.tostring()), len(im2.tostring()))


def test_render_image_to_file():
    i = mapnik.Image(256, 256)

    i.background = mapnik.Color('black')

    if mapnik.has_jpeg():
        i.save('test.jpg')
    i.save('test.png', 'png')

    if os.path.exists('test.jpg'):
        os.remove('test.jpg')
    else:
        return False

    if os.path.exists('test.png'):
        os.remove('test.png')
    else:
        return False

def get_paired_images(w,h,mapfile):
    tmp_map = 'tmp_map.xml'
    m = mapnik.Map(w,h)
    mapnik.load_map(m,mapfile)
    i = mapnik.Image(w,h)
    m.zoom_all()
    mapnik.render(m,i)
    mapnik.save_map(m,tmp_map)
    m2 = mapnik.Map(w,h)
    mapnik.load_map(m2,tmp_map)
    i2 = mapnik.Image(w,h)
    m2.zoom_all()
    mapnik.render(m2,i2)
    os.remove(tmp_map)
    return i,i2    

def test_render_from_serialization():
    try:
        i,i2 = get_paired_images(100,100,'../data/good_maps/building_symbolizer.xml')
        eq_(i.tostring(),i2.tostring())

        i,i2 = get_paired_images(100,100,'../data/good_maps/polygon_symbolizer.xml')
        eq_(i.tostring(),i2.tostring())
    except RuntimeError, e:
        # only test datasources that we have installed
        if not 'Could not create datasource' in str(e):
            raise RuntimeError(e)

def test_render_points():

    if not mapnik.has_cairo(): return

    # create and populate point datasource (WGS84 lat-lon coordinates)
    ds = mapnik.MemoryDatasource()
    context = mapnik.Context()
    context.push('Name')
    f = mapnik.Feature(context,1)
    f['Name'] = 'Westernmost Point'
    f.add_geometries_from_wkt('POINT (142.48 -38.38)')
    ds.add_feature(f)

    f = mapnik.Feature(context,2)
    f['Name'] = 'Southernmost Point'
    f.add_geometries_from_wkt('POINT (143.10 -38.60)')
    ds.add_feature(f)

    # create layer/rule/style
    s = mapnik.Style()
    r = mapnik.Rule()
    symb = mapnik.PointSymbolizer()
    symb.allow_overlap = True
    r.symbols.append(symb)
    s.rules.append(r)
    lyr = mapnik.Layer('Places','+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs')
    lyr.datasource = ds
    lyr.styles.append('places_labels')
    # latlon bounding box corners
    ul_lonlat = mapnik.Coord(142.30,-38.20)
    lr_lonlat = mapnik.Coord(143.40,-38.80)
    # render for different projections 
    projs = { 
        'google': '+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0.0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs +over',
        'latlon': '+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs',
        'merc': '+proj=merc +datum=WGS84 +k=1.0 +units=m +over +no_defs',
        'utm': '+proj=utm +zone=54 +datum=WGS84'
        }
    for projdescr in projs.iterkeys():
        m = mapnik.Map(1000, 500, projs[projdescr])
        m.append_style('places_labels',s)
        m.layers.append(lyr)
        dest_proj = mapnik.Projection(projs[projdescr])
        src_proj = mapnik.Projection('+init=epsg:4326')
        tr = mapnik.ProjTransform(src_proj,dest_proj)
        m.zoom_to_box(tr.forward(mapnik.Box2d(ul_lonlat,lr_lonlat)))
        # Render to SVG so that it can be checked how many points are there with string comparison
        svg_file = os.path.join(tempfile.gettempdir(), 'mapnik-render-points-%s.svg' % projdescr)
        mapnik.render_to_file(m, svg_file)
        num_points_present = len(ds.all_features())
        svg = open(svg_file,'r').read()
        num_points_rendered = svg.count('<image ')
        eq_(num_points_present, num_points_rendered, "Not all points were rendered (%d instead of %d) at projection %s" % (num_points_rendered, num_points_present, projdescr)) 

if __name__ == "__main__":
    setup()
    [eval(run)() for run in dir() if 'test_' in run]