class BBS::Container

A Widget that holds children. It renders them in order, so a later child draws over an earlier one, and passes hit tests and themes down to them.

Attributes

children [R]

The child widgets as an Array, in drawing order.

Public Class Methods

new (**kw)

Source

# File lib/bbs/container.rb, line 11
def initialize(**kw)
  super
  @children = []
end

Creates an empty container. Takes the same keywords as Widget.new.

Calls superclass method

Public Instance Methods

add (child)

Source

# File lib/bbs/container.rb, line 19
def add(child)
  child.parent = self
  @children << child
  child
end

Appends child and makes this container its parent.

Returns child.

clear ()

Source

# File lib/bbs/container.rb, line 32
def clear
  @children.each { |c| c.parent = nil }
  @children.clear
end

Removes all children and clears their parent.

find (id)

Source

# File lib/bbs/container.rb, line 55
def find(id)
  walk { |w| return w if w.id == id }
  nil
end

Returns the first widget in the tree whose id equals id, or nil.

focusable_descendants ()

Source

# File lib/bbs/container.rb, line 39
def focusable_descendants
  result = []
  walk { |w| result << w if w.focusable? && w.visible }
  result
end

Returns an Array of the visible widgets in the tree (this container and every level below) that accept focus, in walk order.

hit_test (x, y)

Source

# File lib/bbs/container.rb, line 69
def hit_test(x, y)
  return nil unless bounds.contains?(x, y) && visible
  # iterate top-most last so we test in reverse
  @children.reverse.each do |child|
    next unless child.visible
    hit = child.hit_test(x, y)
    return hit if hit
  end
  self
end

Returns the top-most visible widget under the screen cell (x, y): the deepest child hit, this container when no child is hit, or nil when the point is outside the bounds or the container is hidden.

remove (child)

Source

# File lib/bbs/container.rb, line 27
def remove(child)
  child.parent = nil if @children.delete(child)
end

Removes child and clears its parent. Does nothing when child is not one of the children.

render (frame)

Source

# File lib/bbs/container.rb, line 62
def render(frame)
  @children.each { |c| c.render(frame) if c.visible }
end

Renders the visible children into frame, a BBS::FrameBuffer, in order.

theme= (value)

Source

# File lib/bbs/container.rb, line 81
def theme=(value)
  super
  @children.each { |c| c.theme = value }
end

Sets the BBS::Theme on this container and on every child.

Calls superclass method

walk () { |self| ... }

Source

# File lib/bbs/container.rb, line 47
def walk(&block)
  yield self
  @children.each do |c|
    c.is_a?(Container) ? c.walk(&block) : (yield c)
  end
end

Yields this container, then every widget below it, depth first in child order. Nested containers are walked in turn.