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module Rubyvis
class Layout
# Alias for Rubyvis::Layout::Indent
def self.Indent
Rubyvis::Layout::Indent
end
# Implements a hierarchical layout using the indent algorithm. This
# layout implements a node-link diagram where the nodes are presented in
# preorder traversal, and nodes are indented based on their depth from the
# root. This technique is used ubiquitously by operating systems to represent
# file directories; although it requires much vertical space, indented trees
# allow efficient <i>interactive</i> exploration of trees to find a specific
# node. In addition they allow rapid scanning of node labels, and multivariate
# data such as file sizes can be displayed adjacent to the hierarchy.
#
# <p>The indent layout can be configured using the <tt>depth</tt> and
# <tt>breadth</tt> properties, which control the increments in pixel space for
# each indent and row in the layout. This layout does not support multiple
# orientations; the root node is rendered in the top-left, while
# <tt>breadth</tt> is a vertical offset from the top, and <tt>depth</tt> is a
# horizontal offset from the left.
#
# <p>For more details on how to use this layout, see
# Rubyvis::Layout::Hierarchy
class Indent < Hierarchy
@properties=Hierarchy.properties.dup
# Constructs a new, empty indent layout. Layouts are not typically constructed
# directly; instead, they are added to an existing panel via
# Rubyvis::Mark.add
def initialize
super
@link.interpolate("step-after")
end
##
# :attr: depth
# The horizontal offset between different levels of the tree; defaults to 15.
#
##
# :attr: breadth
# The vertical offset between nodes; defaults to 15.
#
attr_accessor_dsl :depth, :breadth
# Default properties for indent layouts. By default the depth and breadth
# offsets are 15 pixels.
def self.defaults
Rubyvis::Layout::Indent.new.mark_extend(Rubyvis::Layout::Hierarchy.defaults).
depth(15).
breadth(15)
end
def position(n, breadth, depth)
n.x = @ax + depth * @dspace
depth+=1
n.y = @ay + breadth * @bspace
breadth+=1
n.mid_angle = 0
c=n.first_child
while c
breadth=position(c,breadth,depth)
c=c.next_sibling
end
breadth;
end
private :position
def build_implied(s)
return nil if hierarchy_build_implied(s)
nodes = s.nodes
@bspace = s.breadth
@dspace = s.depth
@ax = 0
@ay = 0
position(nodes[0], 1, 1)
end
end
end
end
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