Issue #11: fix time mode.

Add gradient color detection from the color scale for the given value.

roentgen/constructor.py

@@ -13,11 +13,14 @@
 from roentgen import ui
 from roentgen.extract_icon import DEFAULT_SMALL_SHAPE_ID
 from roentgen.flinger import Flinger
-from roentgen.osm_reader import OSMMember, OSMRelation, OSMWay, OSMNode
+from roentgen.osm_reader import Map, OSMMember, OSMRelation, OSMWay, OSMNode, Tagged
 from roentgen.scheme import IconSet, Scheme
-from roentgen.util import MinMax
+from roentgen.util import MinMax, get_gradient_color
 
 DEBUG: bool = False
+TIME_COLOR_SCALE: List[Color] = [
+    Color("#581845"), Color("#900C3F"), Color("#C70039"), Color("#FF5733"),
+    Color("#FFC300"), Color("#DAF7A6")]
 
 
 def is_clockwise(polygon: List[OSMNode]) -> bool:
@@ -47,23 +50,23 @@ def make_counter_clockwise(polygon: List[OSMNode]) -> List[OSMNode]:
         return list(reversed(polygon))
 
 
-class Node:
+class Node(Tagged):
     """
     Node in Röntgen terms.
     """
     def __init__(
             self, icon_set: IconSet, tags: Dict[str, str],
             point: np.array, coordinates: np.array,
-            priority: int = 0, is_for_node: bool = True):
+            priority: float = 0, is_for_node: bool = True):
         assert point is not None
 
         self.icon_set: IconSet = icon_set
-        self.tags = tags
+        self.tags: Dict[str, str] = tags
         self.point: np.array = point
         self.coordinates: np.array = coordinates
-        self.priority = priority
-        self.layer = 0
-        self.is_for_node = is_for_node
+        self.priority: float = priority
+        self.layer: float = 0
+        self.is_for_node: bool = is_for_node
 
     def get_tag(self, key: str):
         if key in self.tags:
@@ -137,33 +140,14 @@ def get_user_color(text: str, seed: str) -> Color:
     """
     if text == "":
         return Color("black")
-    rgb = sha256((seed + text).encode("utf-8")).hexdigest()[-6:]
-    r = int(rgb[0:2], 16)
-    g = int(rgb[2:4], 16)
-    b = int(rgb[4:6], 16)
-    c = (r + g + b) / 3.
-    cc = 0
-    r = r * (1 - cc) + c * cc
-    g = g * (1 - cc) + c * cc
-    b = b * (1 - cc) + c * cc
-    h = hex(int(r))[2:] + hex(int(g))[2:] + hex(int(b))[2:]
-    return Color("#" + "0" * (6 - len(h)) + h)
-
-
-def get_time_color(time: Optional[datetime]) -> Color:
+    return Color("#" + sha256((seed + text).encode("utf-8")).hexdigest()[-6:])
+
+
+def get_time_color(time: Optional[datetime], boundaries: MinMax) -> Color:
     """
     Generate color based on time.
     """
-    if time is None:
-        return Color("black")
-    delta = (datetime.now() - time).total_seconds()
-    time_color = hex(0xFF - min(0xFF, int(delta / 500000.)))[2:]
-    i_time_color = hex(min(0xFF, int(delta / 500000.)))[2:]
-    if len(time_color) == 1:
-        time_color = "0" + time_color
-    if len(i_time_color) == 1:
-        i_time_color = "0" + i_time_color
-    return Color("#" + time_color + "AA" + i_time_color)
+    return get_gradient_color(time, boundaries, TIME_COLOR_SCALE)
 
 
 def glue(ways: List[OSMWay]) -> List[List[OSMNode]]:
@@ -224,13 +208,13 @@ class Constructor:
     Röntgen node and way constructor.
     """
     def __init__(
-            self, check_level, mode: str, seed: str, map_, flinger: Flinger,
-            scheme: Scheme):
+            self, check_level, mode: str, seed: str, map_: Map,
+            flinger: Flinger, scheme: Scheme):
 
         self.check_level = check_level
         self.mode: str = mode
         self.seed: str = seed
-        self.map_ = map_
+        self.map_: Map = map_
         self.flinger: Flinger = flinger
         self.scheme: Scheme = scheme
 
@@ -300,7 +284,7 @@ def construct_way(
         if self.mode == "time":
             if not way:
                 return
-            time_color = get_time_color(way.timestamp)
+            time_color = get_time_color(way.timestamp, self.map_.time)
             self.ways.append(
                 Way(inners, outers,
                     {"fill": "none", "stroke": time_color.hex,

roentgen/flinger.py

@@ -1,12 +1,14 @@
 """
 Author: Sergey Vartanov (me@enzet.ru)
+
+Geo projection.
 """
 import numpy as np
 
 from roentgen.util import MinMax
 
 
-EQUATOR_LENGTH: float = 40_075_017
+EQUATOR_LENGTH: float = 40_075_017  # (in meters)
 
 
 def pseudo_mercator(coordinates: np.array) -> np.array:
@@ -51,6 +53,8 @@ def __init__(self, geo_boundaries: MinMax, scale: float = 1000):
 
     def fling(self, coordinates: np.array) -> np.array:
         """
+        Convert geo coordinates into SVG position points.
+
         :param coordinates: vector to fling
         """
         result: np.array = self.ratio * (
@@ -63,5 +67,10 @@ def fling(self, coordinates: np.array) -> np.array:
         return result
 
     def get_scale(self, coordinates: np.array) -> float:
+        """
+        Return pixels per meter ratio for the given geo coordinates.
+
+        :param coordinates: geo coordinates
+        """
         scale_factor = 1 / np.cos(coordinates[0] / 180 * np.pi)
         return self.pixels_per_meter * scale_factor

roentgen/util.py

@@ -1,3 +1,5 @@
+from typing import Any, List
+
 from colour import Color
 
 
@@ -23,8 +25,12 @@ def delta(self):
         return self.max_ - self.min_
 
     def center(self):
+        """
+        Get middle point between minimum and maximum.
+        """
         return (self.min_ + self.max_) / 2
 
+
 def is_bright(color: Color) -> bool:
     """
     Is color bright enough to have black outline instead of white.
@@ -33,3 +39,26 @@ def is_bright(color: Color) -> bool:
         0.2126 * color.red * 256 +
         0.7152 * color.green * 256 +
         0.0722 * color.blue * 256 > 200)
+
+
+def get_gradient_color(value: Any, bounds: MinMax, colors: List[Color]):
+    """
+    Get color from the color scale for the value.
+
+    :param value: given value (should be in bounds)
+    :param bounds: maximum and minimum values
+    :param colors: color scale
+    """
+    color_length: int = len(colors) - 1
+    scale = colors + [Color("black")]
+
+    coefficient: float = (
+        0 if bounds.max_ == bounds.min_ else
+        (value - bounds.min_) / (bounds.max_ - bounds.min_))
+    coefficient = min(1.0, max(0.0, coefficient))
+    m: int = int(coefficient * color_length)
+    color_coefficient = (coefficient - m / color_length) * color_length
+
+    return Color(rgb=[
+        scale[m].rgb[i] + color_coefficient *
+        (scale[m + 1].rgb[i] - scale[m].rgb[i]) for i in range(3)])