Re-center hodographs on the upper right quadrant

lib/xmet/hodograph.py

@@ -6,11 +6,11 @@ from typing import Iterable
 from xmet.igra     import IGRAReader
 from xmet.sounding import Sounding, SoundingSample
 
-WIND_SPEED_MAX  = 90 # knots
+WIND_SPEED_MAX  = 100 # knots
-WIND_SPEED_MIN  = 10
+WIND_SPEED_MIN  =  10
-WIND_SPEED_STEP = 10
+WIND_SPEED_STEP =  10
 
-WIND_DIR_STEP = 45 # degrees
+WIND_DIR_STEP = 90 # degrees
 
 PRESSURE_MIN = 100
 
@@ -24,28 +24,40 @@ class Hodograph():
     def __init__(self, width, height):
         self.width  = min(width, height)
         self.height = min(width, height)
-        self.radius = min(width, height) / 2
+        self.radius = min(width, height) * 1.2
 
     def sample_to_screen(self, wind_speed: dir, wind_dir: float) -> tuple:
         r = self.radius * min(wind_speed, WIND_SPEED_MAX) / WIND_SPEED_MAX
 
         return (
-            self.width  / 2 + r * math.cos(radians(wind_dir)),
+            0.1 * self.width  + r * math.cos(radians(wind_dir)),
-            self.height / 2 + r * math.sin(radians(wind_dir))
+            0.9 * self.height + r * math.sin(radians(wind_dir))
         )
 
     def draw_speed_lines(self, cr: cairo.Context, x, y):
+        cr.save()
+
+        cr.set_source_rgb(0.5, 0.5, 0.5)
+        cr.set_line_width(0.5)
+        cr.set_dash([5, 5], 1)
+
         for speed in range(WIND_SPEED_MIN, WIND_SPEED_MAX+1, WIND_SPEED_STEP):
-            cr.arc(x + self.width  / 2,
+            cr.arc(x + 0.1 * self.width,
-                   y + self.height / 2,
+                   y + 0.9 * self.height,
                    self.radius * min(speed, WIND_SPEED_MAX) / WIND_SPEED_MAX,
                    0,
                    2*math.pi)
 
             cr.stroke()
 
+        cr.restore()
+
     def draw_direction_lines(self, cr: cairo.Context, x, y):
-         for angle in range(0, 360+1, WIND_DIR_STEP):
+        cr.save()
+
+        cr.set_source_rgb(0.5, 0.5, 0.5)
+
+        for angle in range(0, 360+1, WIND_DIR_STEP):
             sx1, sy1 = self.sample_to_screen(WIND_SPEED_MAX, angle)
             sx2, sy2 = self.sample_to_screen(WIND_SPEED_MAX, angle + 180)
 
@@ -53,6 +65,8 @@ class Hodograph():
             cr.line_to(x + sx2, y + sy2)
             cr.stroke()
 
+        cr.restore()
+
     def draw_direction_legends(self, cr: cairo.Context, x, y):
         cr.save()
 
@@ -67,8 +81,8 @@ class Hodograph():
             extents = cr.text_extents(text)
             r       = self.radius + ((extents.width + extents.height) / 2)
 
-            sx = self.width  / 2 + r * math.cos(radians(angle))
+            sx = 0.1 * self.width  + r * math.cos(radians(angle))
-            sy = self.height / 2 + r * math.sin(radians(angle))
+            sy = 0.9 * self.height + r * math.sin(radians(angle))
 
             cr.move_to(x + sx - extents.width / 2, y + sy + extents.height / 2)
             cr.show_text(text)
@@ -80,7 +94,7 @@ class Hodograph():
         cr.save()
 
         x_offset_scale = 0.01190476
-        y_offset_scale = 0.02380952
+        y_offset_scale = 0.01
 
         x_offset = x_offset_scale * self.radius
         y_offset = y_offset_scale * self.radius
@@ -157,27 +171,51 @@ class Hodograph():
     def draw_height_legends(self, cr: cairo.Context, x, y):
         width    = 0.02380952 * self.width
         interval = 0.05952380 * self.width
-        offset   = 0
+        offset   = 0.75 * self.width
+
+        cr.save()
+        cr.set_source_rgb(1, 1, 1)
+
+        cr.rectangle(offset + x - width / 2,
+                     y + width,
+                     interval * 4,
+                     width * 3)
+
+        cr.fill()
+
+        cr.set_source_rgb(0.8, 0.8, 0.8)
+        cr.rectangle(offset + x - width / 2,
+                     y + width,
+                     interval * 4,
+                     width * 3)
+        cr.stroke()
+        cr.restore()
 
         for height in self.COLORS:
             color = self.COLORS[height]
 
             cr.save()
             cr.set_source_rgb(*color)
-            cr.rectangle(offset + x, y, width, width)
+            cr.rectangle(offset + x, y + width * 1.5, width, width)
             cr.fill()
             cr.restore()
 
-            cr.rectangle(offset + x, y, width, width)
+            cr.rectangle(offset + x, y + width * 1.5, width, width)
             cr.stroke()
 
-            cr.move_to(offset + x, y + 2*width)
+            cr.move_to(offset + x, y + 3.5*width)
             cr.show_text("%dkm" % (height / 1000))
             cr.stroke()
 
             offset += interval
 
     def draw(self, cr: cairo.Context, x, y, samples: Iterable[SoundingSample]):
+        cr.rectangle(x, y, self.width, self.height)
+        cr.clip()
+
+        cr.rectangle(x, y, self.width, self.height)
+        cr.stroke()
+
         self.draw_speed_lines(cr, x, y)
         self.draw_direction_lines(cr, x, y)
 
@@ -186,3 +224,5 @@ class Hodograph():
         self.draw_speed_legends(cr, x, y)
         self.draw_direction_legends(cr, x, y)
         self.draw_height_legends(cr, x, y)
+
+        cr.reset_clip()