diff --git a/lib/xmet/hodograph.py b/lib/xmet/hodograph.py
index d1c3c2b..963cd08 100644
--- a/lib/xmet/hodograph.py
+++ b/lib/xmet/hodograph.py
@@ -8,7 +8,7 @@ WIND_SPEED_MAX = 140 # knots
WIND_SPEED_MIN = 10
WIND_SPEED_STEP = 10
-WIND_DIR_STEP = 90 # degrees
+WIND_DIR_STEP = 45 # degrees
def radians(degrees: float) -> float:
return (degrees + 90) * (math.pi / 180.0)
@@ -21,72 +21,54 @@ def knots(ms: float) -> float:
class Hodograph():
def __init__(self, width, height):
- self.zoom = 1.2
- self.offset_x = 0.1 # Percentage of the upper left quadrant rendered
- self.offset_y = 0.9 # Percentage of the upper right quadrant rendered
-
- self.min_x = 0
- self.min_y = 0
- self.max_x = 0
- self.max_y = 0
-
- self.width = min(width, height)
- self.height = min(width, height)
- self.radius = min(width, height) * self.zoom
-
- def sample_to_graph(self, wind_speed: dir, wind_dir: float) -> tuple:
- r = self.radius * (wind_speed / WIND_SPEED_MAX)
-
- x = r * math.cos(radians(wind_dir))
- y = r * math.sin(radians(wind_dir))
-
- return x, y
+ self.width = min(width, height)
+ self.height = min(width, height)
+ self.radius = min(width, height) / 2
+ self.extents = None
def sample_to_screen(self, wind_speed: dir, wind_dir: float) -> tuple:
- gx, gy = self.sample_to_graph(wind_speed, wind_dir)
+ r = self.radius * (wind_speed / WIND_SPEED_MAX)
- return (
- self.offset_x * self.width + gx,
- self.offset_y * self.height + gy
- )
+ x = self.radius + r * math.cos(radians(wind_dir))
+ y = self.radius + r * math.sin(radians(wind_dir))
- def find_extents(self, sounding: Sounding):
- """
- Determine the boundaries of the sounding to set the center and zoom
- appropriately.
- """
- for sample in sounding.samples:
- x, y = self.sample_to_graph(sample.wind_speed, sample.wind_dir)
+ if self.extents is None:
+ return x, y
+ else:
+ min_x, min_y = self.extents['min']
+ max_x, max_y = self.extents['max']
- if self.min_x > x:
- self.min_x = x
+ box_width = max_x - min_x
+ box_height = max_y - min_y
+ box = max(box_width, box_height)
- if self.min_y > y:
- self.min_y = y
+ offset_x = self.width * ((box - box_width) / box) / 2
+ offset_y = self.height * ((box - box_height) / box) / 2
- if self.max_x < x:
- self.max_x = x
-
- if self.max_y < y:
- self.max_y = y
-
- self.offset_x = self.min_x / self.radius + 0.1
- self.offset_y = (self.radius - self.max_y) / self.radius
- self.zoom = min(self.width, self.height) / max(self.max_x - self.min_x,
- self.max_y - self.min_y) / 2
- self.radius = min(self.width, self.height) * self.zoom
+ return (
+ offset_x + ((x - min_x) / box) * self.width,
+ offset_y + ((y - min_y) / box) * self.height
+ )
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.offset_x * self.width,
- y + self.offset_y * self.height,
- self.radius * min(speed, WIND_SPEED_MAX) / WIND_SPEED_MAX,
+ cx, cy = self.sample_to_screen(0, 0)
+
+ for speed in range(WIND_SPEED_MIN, 2*WIND_SPEED_MAX, WIND_SPEED_STEP):
+ if speed % (WIND_SPEED_STEP*2) == 0:
+ cr.set_dash([1, 1], 0)
+ else:
+ cr.set_dash([5, 5], 1)
+
+ sx, sy = self.sample_to_screen(speed, 0)
+
+ cr.arc(x + cx,
+ x + cy,
+ sy - self.radius,
0,
2*math.pi)
@@ -98,10 +80,16 @@ class Hodograph():
cr.save()
cr.set_source_rgb(0.5, 0.5, 0.5)
+ cr.set_line_width(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)
+ sx1, sy1 = self.sample_to_screen(2*WIND_SPEED_MAX, angle)
+ sx2, sy2 = self.sample_to_screen(2*WIND_SPEED_MAX, angle + 180)
+
+ if angle % 90 == 0:
+ cr.set_dash([1, 1], 0)
+ else:
+ cr.set_dash([5, 5], 1)
cr.move_to(x + sx1, y + sy1)
cr.line_to(x + sx2, y + sy2)
@@ -112,19 +100,14 @@ class Hodograph():
def draw_speed_legends(self, cr: cairo.Context, x, y):
cr.save()
- x_offset_scale = 0.01190476
- y_offset_scale = 0.01
-
- x_offset = x_offset_scale * self.radius
- y_offset = y_offset_scale * self.radius
-
for speed in range(WIND_SPEED_MIN, WIND_SPEED_MAX, WIND_SPEED_STEP):
text = "%dkt" % speed
extents = cr.text_extents(text)
sx, sy = self.sample_to_screen(speed, 180)
- cr.move_to(x + sx + x_offset, y + sy - y_offset)
+ cr.move_to(x + sx + extents.width * 0.25,
+ y + sy - extents.height * 1.5)
cr.show_text(text)
cr.stroke()
@@ -142,6 +125,54 @@ class Hodograph():
if height < key:
return self.COLORS[key]
+ def each_significant_sample(self, sounding: Sounding):
+ for sample in sounding.samples:
+ if sample.pressure < 0 or sample.pressure is None:
+ continue
+
+ if sample.height is None:
+ continue
+
+ if self.color(sample.height) is None:
+ break
+
+ yield sample
+
+ def find_extents(self, sounding: Sounding):
+ min_x, min_y = None, None
+ max_x, max_y = None, None
+
+ first = True
+
+ for sample in self.each_significant_sample(sounding):
+ sx, sy = self.sample_to_screen(knots(sample.wind_speed),
+ sample.wind_dir)
+
+ if first:
+ min_x = sx
+ max_x = sx
+ min_y = sy
+ max_y = sy
+
+ first = False
+ else:
+ if min_x > sx:
+ min_x = sx
+
+ if min_y > sy:
+ min_y = sy
+
+ if max_x < sx:
+ max_x = sx
+
+ if max_y < sy:
+ max_y = sy
+
+ return {
+ 'min': (min_x, min_y),
+ 'max': (max_x, max_y)
+ }
+
def draw_sounding(self,
cr: cairo.Context,
x,
@@ -154,13 +185,12 @@ class Hodograph():
sx_last = None
sy_last = None
- for sample in sounding.samples:
- if sample.pressure < 0 or sample.pressure is None:
- continue
+ min_x, min_y = self.extents['min']
+ max_x, max_y = self.extents['max']
- if sample.height is None:
- continue
+ box = max(max_x - min_x, max_y - min_y)
+ for sample in self.each_significant_sample(sounding):
color = self.color(sample.height)
if color is None:
@@ -233,17 +263,17 @@ class Hodograph():
offset += interval
def draw(self, cr: cairo.Context, x, y, sounding: Sounding):
- self.find_extents(sounding)
+ self.extents = self.find_extents(sounding)
cr.rectangle(x, y, self.width, self.height)
cr.clip()
- self.draw_speed_lines(cr, x, y)
self.draw_direction_lines(cr, x, y)
-
- self.draw_sounding(cr, x, y, sounding)
+ self.draw_speed_lines(cr, x, y)
self.draw_speed_legends(cr, x, y)
self.draw_height_legends(cr, x, y)
+ self.draw_sounding(cr, x, y, sounding)
+
cr.reset_clip()