def preprocess_tree(root_node):
root_node.weight = 0
root_node.leaf_dist = None
# Step 1: Calculate each node's distance to the farthest leaf node
for node in walk(root_node):
if len(node.children)==0:
node.leaf_dist = 0
while node.parent and ((node.parent.leaf_dist is None) or node.parent.leaf_dist<(node.leaf_dist+1)):
node.parent.leaf_dist = node.leaf_dist+1
node = node.parent
else:
node.leaf_dist = None
# Step 2: Calculate the node weights + tree bounds
bounding_box = dye.BoundingBox()
for node in walk(root_node):
bounding_box.expand(node.x, node.y)
if node.leaf_dist==0:
node.weight = 1
else:
node.weight = node.parent.weight+((1 - node.parent.weight)/float(node.leaf_dist + 1))
root_node.bounds = bounding_box.rect()
def render_tree(root_node, gradient):
with dye.translation(-root_node.bounds.x, -root_node.bounds.y):
for node in walk(root_node):
if node.parent is not None:
x0, y0, x1, y1 = (node.parent.x, node.parent.y, node.x, node.y)
seg_gradient = dye.Gradient(start = gradient.get_interpolated_color(node.parent.weight),
stop = gradient.get_interpolated_color(node.weight))
seg = dye.BezierPath()
seg.move_to(x0, y0)
seg.line_to(x1, y1)
with dye.ContextFrame():
seg.clip_to_outline()
seg_gradient.draw_linear_in_rect(seg.bounds(), math.atan2(x1 - x0, y1 - y0))
