User Guide : Geometry

     About      HowTo      FAQ      Reference documentation

---

wxRuby Geometry classes

Size (Wx::Size) and position (Wx::Point and Wx::RealPoint)

The wxWidgets API has a lot methods that require either wxSize, wxPoint or both type of value as argument. Although this can be specified in C++ still relatively concise like

new wxFrame(nullptr, -1, "title", wxPoint(0,0), wxSize(500,400))

in Ruby this expands to the more verbose

Wx::Frame.new(nil, -1, 'title', Wx::Point.new(0,0), Wx::Size.new(500,400))

which starts to feel awkward to specify what are in essence just pairs of integers.

To provide a simpler, more compact and more Ruby-like, alternative the wxRuby API therefor supports specifying arrays of integer (or float in case of Wx::RealPoint) pairs in (almost) all cases where Wx::Size or Wx::Point (or Wx::RealPoint) is expected. So the following code is equivalent to the previous code:

Wx::Frame.new(nil, -1, 'title', [0,0], [500,400])

In addition Wx::Size, Wx::Point and Wx::RealPoint support parallel assignment semantics such that you can write code like

  win.paint do | dc |
    # ...    
    x, y = win.get_position
    dc.draw_circle(x, y, 4)
    dc.draw_rectangle(x-4, y-4, 8, 8)
  end

instead of

  win.paint do | dc |
    # ...    
    pos = win.get_position
    dc.draw_circle(pos.x, pos.y, 4)
    dc.draw_rectangle(pos.x-4, pos.y-4, 8, 8)
  end

Instances of these classes can also be converted (back) to arrays with their #to_ary methods.

Lastly wxRuby also extends the standard Ruby Array class with conversion methods to explicitly convert arrays to Wx::Size, Wx::Point or Wx::RealPoint; respectively the #to_size, #to_point and #to_real_point methods.

Areas (Wx::Rect)

Like Wx::Size and Wx::Point wxRuby supports parallel assignment for Wx::Rect such that you can write code like

x, y, width, height = win.get_client_rect

Providing arrays of integers as alternative for Wx::Rect arguments is not supported as specifying [0, 0, 20, 40] is ambiguous. This could either mean a rectangle with origin x=0,y=0 and size width=20,height=40 (Wx::Rect.new(0,0,20,40)) or a rectangle from origin top left x=0,y=0 to point bottom right x=20,y=40 (Wx::Rect.new(Wx::Point.new(0,0), Wx::Point.new(20,40))).