Add Răhukăla display to the generated SVG

seasonal_clock/svg.py

@@ -1,12 +1,12 @@
 from datetime import datetime, time
 from math import ceil, cos, pi, radians, sin
-from typing import Union
+from typing import Optional, Union
 
 from astral import LocationInfo, moon
 from pytz import UTC, timezone
 
 from .config import load_config
-from .times import collect_day_parts
+from .times import collect_day_parts, get_rahukaalam_times
 
 HOURS_AMPM = (
     'Midnight',
@@ -94,7 +94,9 @@ def hex_to_rgb(hex_color: str) -> str:
     g = int(hex_color[3:5], 16)
     b = int(hex_color[5:7], 16)
 
-    return f'rgb({r}, {g}, {b})'
+    ret = f'rgb({r}, {g}, {b})'
+
+    return ret
 
 
 def get_utc_offset(utc_time: datetime, local_time: datetime):
@@ -160,12 +162,10 @@ def hour_marker(
     hour_name_y = image_width / 2 - outer_r + ring_width / 2 + hour_name_font_size / 4
     utc_hour_y = image_width / 2 - outer_r + ring_width + utc_font_size
 
-    ret = f'''<g class="hour {season}" transform="rotate(-172.5, {image_width / 2}, {image_width / 2}) rotate({rotation}, {image_width / 2}, {image_width / 2})">
+    ret = f'''<g class="hour {season}" transform="rotate({rotation - 172.5}, {image_width / 2}, {image_width / 2})">
     <path
         d="M {x1} {y1} a {outer_r} {outer_r} 15 0 1 {2 * delta_x} 0 l {s_delta_x} {s_delta_y} a {outer_r - ring_width} {outer_r - ring_width} 15 0 0 {i_delta_x} 0 z"></path>
     <text
-        x="{image_width / 2}"
-        y="{hour_name_y}"
         text-anchor="middle"
         dominant-baseline="mathematical"
         font-size="{hour_name_font_size}"><textPath xlink:href="#hour-name-path" startOffset="50%">{hour_name}</textPath></text>
@@ -194,7 +194,7 @@ def local_hour(
 
     return indent_lines(
         f'''<text
-    transform="rotate(180, {image_width / 2}, {image_width / 2}) rotate({rotation}, {image_width / 2}, {image_width / 2})"
+    transform="rotate({180 + rotation}, {image_width / 2}, {image_width / 2})"
     class="local-hour"
     x="{image_width / 2}"
     y="{image_width / 2 - outer_r - font_size / 2}"
@@ -260,6 +260,55 @@ C {h2_x} {bottom_y}, {h2_x} {top_y}, {image_width / 2} {image_width / 2 - radius
     return indent_lines(ret, indent)
 
 
+def draw_rahukaala(
+        image_width: float,
+        rahukaala_radius: float,
+        rahukaala_width: float,
+        sun_radius: float,
+        start: datetime,
+        end: datetime,
+        indent: int = 8,
+) -> str:
+    start_deg = time_to_degrees(start)
+    end_deg = time_to_degrees(end)
+    alpha = radians(end_deg - start_deg)
+
+    delta_x = -rahukaala_radius * sin(alpha)
+    delta_y = -rahukaala_radius * (1 - cos(alpha))
+
+    inner_delta_x = -(rahukaala_radius - rahukaala_width) * sin(alpha)
+    inner_delta_y = -(rahukaala_radius - rahukaala_width) * (1 - cos(alpha))
+
+    s_delta_x = rahukaala_width * sin(alpha)
+    s_delta_y = -rahukaala_width * cos(alpha)
+
+    i_delta_x = -2 * (rahukaala_radius - rahukaala_width) * sin(alpha)
+
+    x1 = image_width / 2
+    y1 = image_width / 2 + rahukaala_radius
+
+    x2 = x1 + delta_x
+    y2 = y1 + delta_y
+
+    x4 = x1
+    y4 = y1 - rahukaala_width
+
+    x3 = x4 + inner_delta_x
+    y3 = y4 + inner_delta_y
+
+    ret = f'''<path
+    transform="rotate({start_deg}, {image_width / 2}, {image_width / 2})"
+    class="rahukaala"
+    d="M {x1} {y1}
+    A {rahukaala_radius} {rahukaala_radius} {end_deg - start_deg} 0 1 {x2} {y2}
+    A {sun_radius} {sun_radius} 180 1 1 {x3} {y3}
+    A {rahukaala_radius - rahukaala_width} {rahukaala_radius - rahukaala_width} {end_deg - start_deg} 0 0 {x4} {y4}
+    A {sun_radius} {sun_radius} 180 1 1 {x1} {y1}
+    z"></path>'''
+
+    return indent_lines(ret, indent)
+
+
 def get_svg_data(
     local_time: datetime,
     image_width: int = 700,
@@ -276,6 +325,8 @@ def get_svg_data(
     golden_color: str = '#aa842c',
     day_color: str = '#7dc5f0',
     moon_color: str = '#aaaaaa',
+    rahukaala_color: str = '#ff7777',
+    rahukaala_alpha: Optional[int] = None,
     local_hour_font_size: float = 16.5,
     hour_name_font_size: float = 13.37699,
     utc_hour_font_size: float = 15.0234,
@@ -293,6 +344,7 @@ def get_svg_data(
     golden_rgb = hex_to_rgb(golden_color)
     day_rgb = hex_to_rgb(day_color)
     moon_rgb = hex_to_rgb(moon_color)
+    rahukaala_rgb = hex_to_rgb(rahukaala_color)
     hours = HOURS_24 if hour_24 else HOURS_AMPM
     outer_r = image_width / 2 - 3 * hour_name_font_size
     ring_width = hour_name_font_size * 3
@@ -325,6 +377,12 @@ def get_svg_data(
     noon = day_parts_dict.pop('noon')
     midnight = day_parts_dict.pop('midnight')
 
+    if rahukaala_alpha is not None:
+        value = rahukaala_alpha / value
+        rahukaala_opacity = f' fill-opacity: {value:.2f};'
+    else:
+        rahukaala_opacity = ''
+
     ret = f'''<svg width="{image_width}" height="{image_width}" xmlns:xlink="http://www.w3.org/1999/xlink">
     <style>
         .hour path {{stroke: {hname_stroke_rgb}; stroke-width: {line_width};}}
@@ -344,6 +402,7 @@ def get_svg_data(
         .moon {{stroke: none; fill: {moon_rgb};}}
         .sun {{stroke: none; fill: {line_rgb};}}
         .dial {{stroke-width: 2px; stroke: {line_rgb};}}
+        .rahukaala {{stroke: none; fill: {rahukaala_rgb};{rahukaala_opacity}}}
     </style>
     <defs>
         {hour_name_path(image_width, outer_r, ring_width)}
@@ -397,6 +456,12 @@ def get_svg_data(
         evening_blue_end.time(),
     )
 
+    rahukaala_radius = outer_r / 2 + 2 * sun_radius
+    rahukaala_width = 2 * sun_radius
+
+    for start, end in get_rahukaalam_times(location.observer, local_time):
+        ret += draw_rahukaala(image_width, rahukaala_radius, rahukaala_width, sun_radius, start, end)
+
     ret += f'''        <circle cx="{image_width / 2}" cy="{image_width / 2}" r="{marker_radius}" class="marker"></circle>
     </g>
     <g>\n'''