add weather demo

Signed-off-by: Mattias Andrée <maandree@operamail.com>

2 files changed, 72 insertions, 1 deletions

diff --git a/examples/comprehensive b/examples/comprehensive
index 8c6b45d..8ec121d 100644
--- a/examples/comprehensive
+++ b/examples/comprehensive
@@ -3,7 +3,7 @@
 # This example covers most of what Blueshift offers. For a complete
 # coverage of Blueshift complement this example with:
 #   backlight, crtc-detection, crtc-searching, logarithmic,
-#   stored-settings, modes, textconf
+#   stored-settings, modes, textconf, weather
 # However the are features that are only covered by the info manual:
 #   Methods for calculating correlated colour temperature
 
diff --git a/examples/weather b/examples/weather
new file mode 100644
index 0000000..5291fb6
--- /dev/null
+++ b/examples/weather
@@ -0,0 +1,71 @@
+# -*- python -*-
+
+# This example demonstrates how to include weather conditions
+# in you configuration scripts.
+
+
+# Copyright © 2014  Mattias Andrée (maandree@member.fsf.org)
+# 
+# Permission is granted to copy, distribute and/or modify this document
+# under the terms of the GNU Free Documentation License, Version 1.3
+# or any later version published by the Free Software Foundation;
+# with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
+# You should have received a copy of the GNU General Public License
+# along with this software package.  If not, see <http://www.gnu.org/licenses/>.
+
+
+# Geographical coodinates.
+# ("Kristall, vertikal accent i glas och stål" (Crystal, vertical accent
+# in glass and steal) in this example. A glas obelisk, lit from the inside
+# with adjustable colours and a default colour of 5600 K, in the middle
+# of a hyperelliptic roundabout.)
+latitude, longitude = 59.3326, 18.0652
+
+# International Civil Aviation Organization (ICAO)
+# code of the nearest airport.
+# (Stockholm Bromma Airport in this example.)
+airport = 'ESSB'
+
+# The colour temperature at day and at night.
+temperature_day, temperature_night = 6500, 3700
+
+# Dayness modifiers based on weather and sky conditions.
+modifiers = { 'clear'         : 1.00
+            , 'mostly clear'  : 0.95
+            , 'partly cloudy' : 0.90
+            , 'mostly cloudy' : 0.85
+            , 'overcast'      : 0.80
+            , 'obscured'      : 0.75
+            }
+
+# The maximum for visibility range for when to
+# account for the visibility range.
+visibility_max = 4
+
+
+# The visibility of the Sun.
+dayness = sun(latitude, longitude)
+
+# Get weather report.
+metar = weather(airport)
+
+# Account for weather.
+if metar is not None:
+    conditions = [metar[0]] + metar[2]
+    for condition in conditions:
+        if condition in modifiers:
+            dayness *= modifiers[condition]
+    _bound, visibility = metar[1]
+    if (visibility_max is not None) and (visibility is not None):
+        if visibility < visibility_max:
+            dayness *= visibility / visibility_max
+
+# Calculation of the colour temperature.
+temp = temperature_day * dayness + temperature_night * (1 - dayness)
+
+## Calculate the whitepoint with adjusted colour temperature.
+whitepoint = temperature(temp, lambda t : divide_by_maximum(cmf_10deg(t)))
+
+# Apply adjustments.
+randr(0)
+