def mapnik_style(self, value_field=None):
"""Return a Mapnik style from Legend object. """
mapnik_style = mapnik.Style()
if value_field is None:
value_field = "value"
# Default color: red.
mapnik_rule = point_rule(
self.icon, self.mask, self.default_color)
mapnik_style.rules.append(mapnik_rule)
# < min
mapnik_filter = "[%s] <= %f" % (value_field, self.min_value)
logger.debug('adding mapnik_filter: %s' % mapnik_filter)
mapnik_rule = point_rule(
self.icon, self.mask, self.too_low_color,
mapnik_filter=mapnik_filter)
mapnik_style.rules.append(mapnik_rule)
# in boundaries
for legend_value in self.legend_values():
mapnik_filter = "[%s] > %f and [%s] <= %f" % (
value_field, legend_value['low_value'],
value_field, legend_value['high_value'])
logger.debug('adding mapnik_filter: %s' % mapnik_filter)
mapnik_rule = point_rule(
self.icon, self.mask, legend_value['color'],
mapnik_filter=mapnik_filter)
mapnik_style.rules.append(mapnik_rule)
# > max
mapnik_filter = "[%s] > %f" % (value_field, self.max_value)
logger.debug('adding mapnik_filter: %s' % mapnik_filter)
mapnik_rule = point_rule(
self.icon, self.mask, self.too_high_color,
mapnik_filter=mapnik_filter)
mapnik_style.rules.append(mapnik_rule)
return mapnik_style
def mapnik_style(self, value_field=None):
"""
Generates mapnik style from this object.
"""
if value_field is None:
value_field = 'value'
style = mapnik.Style()
classes = self.shapelegendsingleclass_set.all()
# Add a rule for each class
for c in classes:
layout_rule = mapnik.Rule()
if c.color_inside:
area_looks = mapnik.PolygonSymbolizer(
mapnik.Color('#' + c.color_inside))
area_looks.fill_opacity = 0.5
layout_rule.symbols.append(area_looks)
logger.debug('adding polygon symbolizer')
if c.color:
line_looks = mapnik.LineSymbolizer(
mapnik.Color('#' + c.color), c.size)
layout_rule.symbols.append(line_looks)
logger.debug('adding line symbolizer')
mapnik_filter = None
if c.is_exact or c.min_value and c.min_value == c.max_value:
# Check if c.min_value is parsable as float. Yes:
# compare like float.
try:
float(c.min_value)
mapnik_filter = str("[%s] = %s" % (
value_field, c.min_value))
except ValueError:
mapnik_filter = str("[%s] = '%s'" % (
value_field, c.min_value))
else:
if c.min_value and c.max_value:
mapnik_filter = str("[%s] >= %s and [%s] < %s"
% (value_field,
c.min_value,
value_field,
c.max_value))
elif c.min_value and not c.max_value:
mapnik_filter = str("[%s] >= %s"
% (value_field,
c.min_value))
elif not c.min_value and c.max_value:
mapnik_filter = str("[%s] < %s"
% (value_field,
c.max_value))
if mapnik_filter is not None:
logger.debug('adding mapnik_filter: %s' % mapnik_filter)
layout_rule.filter = mapnik.Filter(mapnik_filter)
style.rules.append(layout_rule)
# Add icon rule, if applicable.
if c.icon:
style.rules.append(
point_rule(c.icon, c.mask,
c.color, mapnik_filter))
return style
