Module: GlimR::Layoutable

Included in:
Widget
Defined in:
lib/glimr/layoutable.rb

Overview

Layoutable is a mixin for creating GlimR nodes that are suspectible to layout rules.

Layoutable objects have dimensions, margins, and padding.

The margins define how much space should be left around the Layoutable. Padding defines how much distance should be left between the borders of the Layoutable and its child nodes.

They also have the following attributes that control their dynamic resizing behaviour: expand_width, expand_height, fit_children, min_width, min_height, max_width and max_height.

Dynamic layout rules:

An object expands in a dimension if either its corresponding expand attribute is set to true, or if its fit_children is set to true and one of its children expands in the dimension.

If an object neither fits its children nor expands, it is a constant size object.

When a layoutable object is attached to the scene graph it expands to its maximum dimensions if it is an expanding object.

When a layoutable object changes size, it informs its parent if the parent is a layoutable. If the object was a constant size object, or the size change resulted from changing the object’s dimension constraints (min_width, max_width, etc.), the expanding children of the object are also informed of the size change.

When computing the dimensions of a Layoutable, dimension constraints take predecence over expanding, which takes predecence over fit_children.

E.g. the final width of a layoutable node is computed as follows:

1. set width to max child width if fit_children
2. set width to the inner width of the parent node if expand_width
3. clamp the width between min_width and max_width if they're set

Constant Summary collapse

DIMENSIONS =

, :front, :back]

[:left, :right, :top, :bottom]

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#align ⇒ Object

Returns the value of attribute align.



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# File 'lib/glimr/layoutable.rb', line 72

def align
  @align
end

#valign ⇒ Object

Returns the value of attribute valign.



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# File 'lib/glimr/layoutable.rb', line 72

def valign
  @valign
end

Class Method Details

.size_changing_accessor(*mnames) ⇒ Object 



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# File 'lib/glimr/layoutable.rb', line 51

def self.size_changing_accessor(*mnames)
  attr_reader *mnames
  mnames.each{|mn|
    ivar_name = :"@#{mn}"
    define_method("#{mn}=") do |value|
      size_changing{ instance_variable_set(ivar_name, value) }
    end
  }
end

Instance Method Details

#attach(*a, &b) ⇒ Object 



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# File 'lib/glimr/layoutable.rb', line 272

def attach(*a, &b)
  size_changing{
    super
    children_change
  }
end

#children_change ⇒ Object

Children changed, let’s accommodate.



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# File 'lib/glimr/layoutable.rb', line 351

def children_change
  fit_to_children! if fit_children?
  layout
end

#constant_size? ⇒ Boolean

Returns true if the object’s size is constant, i.e it does not expand and does not fit its children.

Returns:

  • (Boolean) 


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# File 'lib/glimr/layoutable.rb', line 268

def constant_size?
  not (expand? or fit_children?)
end

#default_config ⇒ Object 



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# File 'lib/glimr/layoutable.rb', line 85

def default_config
  super.merge(
    :expand_width => false, :expand_height => false,
    :fit_children => true, :align => :left, :valign => :top,
    :min_width => 0, :min_height => 0,
    :max_width => 1.0/0.0, :max_height => 1.0/0.0,
    :width => 0, :height => 0, :depth => 0,
    :margin_left => 0, :margin_right => 0,
    :margin_top => 0, :margin_bottom => 0,
    :margin_front => 0, :margin_back => 0,
    :padding_left => 0, :padding_right => 0,
    :padding_top => 0, :padding_bottom => 0,
    :padding_front => 0, :padding_back => 0
  )
end

#detach(*a, &b) ⇒ Object 



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# File 'lib/glimr/layoutable.rb', line 279

def detach(*a, &b)
  size_changing{
    super
    children_change
  }
end

#expand!(given_width = nil, given_height = nil) ⇒ Object

Expands self to maximum available dimensions. Brought on by parent size change.



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# File 'lib/glimr/layoutable.rb', line 364

def expand!(given_width=nil,given_height=nil)
  size_changing{
    expand_to_max_width!(given_width) if expand_width
    expand_to_max_height!(given_width) if expand_height
  }
end

#expand? ⇒ Boolean

Whether the Layoutable object expands to fill its parent’s width or height.

Returns:

  • (Boolean) 


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# File 'lib/glimr/layoutable.rb', line 262

def expand?
  expand_width or expand_height
end

#expand_height ⇒ Object

Whether the object expands to fill its parent’s height or not.

Returns true if either @expand_height is true or fit_children is true and any of the layoutable children returns true to #expand_height.



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# File 'lib/glimr/layoutable.rb', line 255

def expand_height
  @expand_height or (fit_children and
  layoutable_children.any?{|c| c.expand_height })
end

#expand_to_max_height!(given_height = nil) ⇒ Object

Expands self, parent and children to maximum available height if expand_height is true.

If expand_height is true, expands to either the given_height, the result of calling @parent.expand_to_max_height! or If height changes as a result of this call, calls each Layoutable child’s expand_to_max_height! with the new height.

Returns free_height.



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# File 'lib/glimr/layoutable.rb', line 414

def expand_to_max_height!(given_height=nil)
  if expand_height
    remove_event_listener(:resize, @__resize_handler)
    if given_height
      @height = given_height
    elsif @parent.is_a? Layoutable
      @height = @parent.expand_to_max_height!
    elsif @viewport ||= (@parent && @parent.viewport)
      on_resize(@__resize_handler)
      @height = @viewport.height
    end
  end
  free_height
end

#expand_to_max_width!(given_width = nil) ⇒ Object

Expands self, parent and children to maximum available width if expand_width is true.

If expand_width is true, expands to either the given_width, the result of calling @parent.expand_to_max_width! or If width changes as a result of this call, calls each Layoutable child’s expand_to_max_width! with the new width.

Returns free_width.



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# File 'lib/glimr/layoutable.rb', line 385

def expand_to_max_width!(given_width=nil)
  if expand_width
    remove_event_listener(:resize, @__resize_handler)
    if given_width
      @width = given_width
    elsif @parent.is_a? Layoutable
      @width = @parent.expand_to_max_width!
    elsif @viewport ||= (@parent && @parent.viewport)
      on_resize(@__resize_handler)
      @width = @viewport.width
    end
  end
  free_width
end

#expand_width ⇒ Object

Whether the object expands to fill its parent’s width or not.

Returns true if either @expand_width is true or fit_children is true and any of the layoutable children returns true to #expand_width.



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# File 'lib/glimr/layoutable.rb', line 237

def expand_width
  @expand_width or (fit_children and layoutable_children.any?{|c| c.expand_width })
end

#fit_height! ⇒ Object

Sets height equal to the largest child + padding.



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# File 'lib/glimr/layoutable.rb', line 302

def fit_height!
  self.height = layoutable_children.map{|c|
    c.full_height + padding_top + padding_bottom
  }.max unless layoutable_children.empty?
end

#fit_to_children! ⇒ Object

Sets dimensions equal to the largest child + padding.



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# File 'lib/glimr/layoutable.rb', line 287

def fit_to_children!
  size_changing do
    fit_width! unless parent and expand_width
    fit_height! unless parent and expand_height
  end
end

#fit_width! ⇒ Object

Sets width equal to the largest child + padding.



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# File 'lib/glimr/layoutable.rb', line 295

def fit_width!
  self.width = layoutable_children.map{|c|
    c.full_width + padding_left + padding_right
  }.max unless layoutable_children.empty?
end

#free_height ⇒ Object

Returns the maximum height an expanding child can expand to.



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# File 'lib/glimr/layoutable.rb', line 458

def free_height
  inner_height
end

#free_width ⇒ Object

Returns the maximum width an expanding child can expand to.



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# File 'lib/glimr/layoutable.rb', line 453

def free_width
  inner_width
end

#full_depth ⇒ Object 



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# File 'lib/glimr/layoutable.rb', line 501

def full_depth
  case scale
  when Numeric
    depth * scale
  when Array
    depth * scale[2]
  else
    depth
  end + @margin_front + @margin_back
end

#full_height ⇒ Object

Height, scaled, plus margins.



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# File 'lib/glimr/layoutable.rb', line 490

def full_height
  case scale
  when Numeric
    height * scale
  when Array
    height * scale[1]
  else
    height
  end + @margin_top + @margin_bottom
end

#full_width ⇒ Object

Width, scaled, plus margins.



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# File 'lib/glimr/layoutable.rb', line 478

def full_width
  case scale
  when Numeric
    width * scale
  when Array
    width * scale[0]
  else
    width
  end + @margin_left + @margin_right
end

#initialize(*a, &b) ⇒ Object 



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# File 'lib/glimr/layoutable.rb', line 101

def initialize(*a, &b)
  super
  @__resize_handler = lambda{|o,e| o.expand! }
  self.margin = @margin if @margin
  self.padding = @padding if @padding
end

#inner_depth ⇒ Object

Depth sans padding.



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# File 'lib/glimr/layoutable.rb', line 473

def inner_depth
  @depth - @padding_front - @padding_back
end

#inner_height ⇒ Object

Height sans padding.



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# File 'lib/glimr/layoutable.rb', line 468

def inner_height
  @height - @padding_bottom - @padding_top
end

#inner_width ⇒ Object

Width sans padding.



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# File 'lib/glimr/layoutable.rb', line 463

def inner_width
  @width - @padding_left - @padding_right
end

#inspect ⇒ Object 



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# File 'lib/glimr/layoutable.rb', line 512

def inspect
  super[0..-2] + "::w#@width:h#@height>"
end

#layout ⇒ Object 



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# File 'lib/glimr/layoutable.rb', line 429

def layout
  @layouted_width = @width
  @layouted_height = @height
  layoutable_children.each{|c|
    case align
    when :left
      c.x = padding_left + c.margin_left
    when :right
      c.x = width - padding_right - c.full_width
    when :center
      c.x = padding_left + c.margin_left + ((inner_width - c.margin_left - c.margin_right) - c.width) / 2.0
    end
    case valign
    when :top
      c.y = padding_top + c.margin_top
    when :bottom
      c.y = height - padding_bottom - c.full_height
    when :middle
      c.y = padding_top + c.margin_top + ((inner_height - c.margin_top - c.margin_bottom) - c.height) / 2.0
    end
  }
end

#layoutable_children ⇒ Object

Returns an Array of all children that respond true to #is_a?(Layoutable).



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# File 'lib/glimr/layoutable.rb', line 229

def layoutable_children
  children.find_all{|c| c.is_a? Layoutable }
end

#margin ⇒ Object

Returns current margins as an OpenStruct with #left, #right, #top, and #bottom.



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# File 'lib/glimr/layoutable.rb', line 165

def margin
  OpenStruct.new(
    :left => margin_left, :right => margin_right,
    :top => margin_top, :bottom => margin_bottom,
    :front => margin_front, :back => margin_back
  )
end

#margin=(new_margin) ⇒ Object

Sets margins to new_margin. If given a Numeric, sets all margins to the given value. If given a hash, sets the margins to the corresponding values in the hash. If given any other object, acts as if it is an OpenStruct returned by #margin.



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# File 'lib/glimr/layoutable.rb', line 178

def margin= new_margin
  size_changing do
    case new_margin
    when Numeric
      @margin_left = @margin_right = @margin_top = @margin_bottom = new_margin
      touch!
    when Hash
      new_margin.each{|k,v|
        __send__("margin_#{k}=", v)
      }
    else
      DIMENSIONS.each{|d|
        __send__("margin_#{d}=", new_margin.__send__(d))
      }
    end
  end
end

#max_height=(mh) ⇒ Object

Sets max_height to mw and sets height to max_height if it’s larger than the new max_height.



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# File 'lib/glimr/layoutable.rb', line 159

def max_height= mh
  @max_height = mh
  self.height = mh if self.height > mh
end

#max_width=(mw) ⇒ Object

Sets max_width to mw and sets width to max_width if it’s larger than the new max_width.



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# File 'lib/glimr/layoutable.rb', line 152

def max_width= mw
  @max_width = mw
  self.width = mw if self.width > mw
end

#min_height=(mh) ⇒ Object

Sets min_height to mw and sets height to min_height if it’s smaller than the new min_height.



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# File 'lib/glimr/layoutable.rb', line 144

def min_height= mh
  @min_height = mh
  self.height = mh if self.height < mh
  fit_to_children! if fit_children?
end

#min_width=(mw) ⇒ Object

Sets min_width to mw and sets width to min_width if it’s smaller than the new min_width.



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# File 'lib/glimr/layoutable.rb', line 136

def min_width= mw
  @min_width = mw
  self.width = mw if self.width < mw
  fit_to_children! if fit_children?
end

#padding ⇒ Object

Returns current padding as an OpenStruct with #left, #right, #top, and #bottom.



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# File 'lib/glimr/layoutable.rb', line 197

def padding
  OpenStruct.new(
    :left => padding_left, :right => padding_right,
    :top => padding_top, :bottom => padding_bottom,
    :front => padding_front, :back => padding_back
  )
end

#padding=(new_padding) ⇒ Object

Sets padding to new_padding. If given a Numeric, sets all paddings to the given value. If given a hash, sets the paddings to the corresponding values in the hash. If given any other object, acts as if it is an OpenStruct returned by #padding.



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# File 'lib/glimr/layoutable.rb', line 210

def padding= new_padding
  size_changing do
    case new_padding
    when Numeric
      @padding_left = @padding_right = @padding_top = @padding_bottom = new_padding
      touch!
    when Hash
      new_padding.each{|k,v|
        __send__("padding_#{k}=", v)
      }
    else
      DIMENSIONS.each{|d|
        __send__("padding_#{d}=", new_padding.__send__(d))
      }
    end
  end
end

#parent=(p) ⇒ Object 



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# File 'lib/glimr/layoutable.rb', line 241

def parent= p
  super
  ew = expand_width
  eh = expand_height
  viewport_expand = p.is_a?(Viewport) and (ew or eh)
  constant_expand = (p.is_a?(Layoutable) and !p.fit_children?) and
    ((ew and !parent.expand_width) or (eh and !parent.expand_height))
  expand! if (viewport_expand or constant_expand)
end

#size_changing(&block) ⇒ Object

Yields to block and informs relevant parties if size changed during it.

In detail:

If the node turns into an expanding one, it is expanded. This may cause a size change.

If the inner dimensions (caused by padding changes) are altered, children are told and relayouted.

If the outer dimensions (caused by dimension changes and margin changes) are altered, children are told and relayouted and possible Layoutable parent is told (unless the node is an expanding one, in which case the parent already knows.)



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# File 'lib/glimr/layoutable.rb', line 321

def size_changing(&block)
  return yield if @__doing_size_changing_operation
  @__doing_size_changing_operation = true
  ow, oh, iw, ih = full_width, full_height, inner_width, inner_height
  cs = constant_size?
  fc = fit_children?
  ew = expand_width
  eh = expand_height
  rv = yield
  fit_to_children! if fit_children? and ((!fc and fit_children?) or (ew and !expand_width) or (eh and !expand_height))
  expand! if (!ew and expand_width) or (!eh and expand_height)
  @width = [[min_width, width].max, max_width].min
  @height = [[min_height, height].max, max_height].min
  dw = (ow != full_width)
  dh = (oh != full_height)
  diw = (iw != inner_width)
  dih = (ih != inner_height)
  if dw or dh or diw or dih
    tell_children_of_size_change if diw or dih
    parent.children_change if parent.is_a?(Layoutable) and (dw or dh)
    layout
    dispatch_event(Event.new(:layout)) if respond_to? :dispatch_event
    @width = [[min_width, width].max, max_width].min
    @height = [[min_height, height].max, max_height].min
  end
  @__doing_size_changing_operation = false
  rv
end

#tell_children_of_size_change ⇒ Object

Expands all expanding children.



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# File 'lib/glimr/layoutable.rb', line 357

def tell_children_of_size_change
  layoutable_children.each{|c| c.expand! if c.expand? }
end

#x=(nx) ⇒ Object

Sets x to the given integer value.



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# File 'lib/glimr/layoutable.rb', line 109

def x= nx
  super nx.to_i
end

#y=(ny) ⇒ Object

Sets y to the given integer value.



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# File 'lib/glimr/layoutable.rb', line 114

def y= ny
  super ny.to_i
end