[Hiki] update - tips_layout_example (ruby-gnome2-doc-cvs) - Ruby-GNOME2

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REMOTE_ADDR = 128.88.255.106
REMOTE_HOST = 
        URL = http://ruby-gnome2.sourceforge.jp//?tips_layout_example
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+ =How to use the mouse to move widgets in a Layout container
  {{link nil, "Ruby-GNOME2+Tips", nil, nil}}

- =How to use the mouse to move widgets in a Layout container
+ Most of the layout containers have the responsibility of positioning the widgets that are put into them. But there is an exception: the Gtk::Layout container. With a Gtk::Layout container, you can determine the x,y coordinates of the widget. Thus, by using the mouse and its x,y pointer, it's possible to position the widget wherever you want it inside the Gtk::Layout container.

- Most of the layout containers have the responsibility of positioning the widgets that are put into them. But there is an exception: the Layout container. With a Layout container, you can determine the x,y coordinates of the widget. Thus, by using the mouse and its x,y pointer, it's possible to position the widget wherever you want it inside the Layout container.
+ Not all widgets can receive mouse events by default. Those that can, have a window handle. If a widget does not have a window handle, and you want it to receive some events that it doesn't, then you should put the widget in an Gtk::EventBox, and use that as the source of the events. An Gtk::EventBox does have a window handle.

- Not all widgets can receive mouse events by default. Those that can, have a window handle. If a widget does not have a window handle, and you want it to receive some events that it doesn't, then you should put the widget in an EventBox, and use that as the source of the events. An EventBox does have a window handle.
- 
  If the widget that has a window handle isn't receiving the events, then the following method call on it should make it receive them.

   set_events(Gdk::Event::ALL_EVENTS_MASK)

  This is a screenshot of this example:

  {{image_left "layout_example.png"}}

  {{br}}

  Usage: double click to create a new Note Window. Click on the Note Window and drag it wherever you want it.

  This is the code for this example:

    require 'gtk2'
    include Gtk

    class NoteLayout < Layout
      attr_reader :widgets
      def initialize
        super()
        @widgets = {}
      end
      def put widget, x, y
        super(widget, x, y)
        @widgets[widget] = [x,y]
      end
      def move widget, x, y
        super(widget, x, y)
        @widgets[widget] = [x,y]
      end
      def [] widget
        @widgets[widget]
      end
    end

    class NoteWindow < EventBox
      def initialize
        super()
        @vbox = VBox.new
        add @vbox
        @title_box = Frame.new()
        @vbox.pack_start evbox_title = EventBox.new.add(@title_box), true, false, 0
        @title_box.add @label = Label.new("Hi!")
        @tv = TextView.new
        tv_scroll = ScrolledWindow.new
        tv_scroll.set_policy(POLICY_AUTOMATIC, POLICY_AUTOMATIC)
        tv_scroll.add_with_viewport @tv
        @vbox.pack_start tv_scroll, true, true, 0
        set_size_request 200,100
        #@title_box.set_events(Gdk::Event::ALL_EVENTS_MASK)
        signal_connect('button-press-event'){|owner, ev|
          if @clicked_block != nil
            @clicked_block.call(owner, ev)
          end
          true
        }
        evbox_title.signal_connect('button-press-event'){|owner, ev|
          if @clicked_block != nil
            @clicked_block.call(owner, ev)
          end
          true
        }
        @tv.signal_connect('button-press-event'){|owner, ev|
          if @clicked_block != nil
            @clicked_block.call(owner, ev)
          end
          true
        }
      end
      def title= v
        @label.text = v
      end
      def on_clicked &block
        @clicked_block = block
      end
      def grab_focus
        @tv.grab_focus
      end
    end

    def create_note x,y, title = nil
      @layout.put(nw = NoteWindow.new, x, y)
      if title != nil
        nw.title = title
      end
      nw.on_clicked{|owner, ev|
        @note_being_dragged = nw
        handle_layout_click owner,  ev
      }
      #@layout.put(NoteWindow.new, 200, 10)
      nw.show_all
      nw
    end

    def get_note_pointer nw = nil
      if @note_being_dragged != nil
        @layout[@note_being_dragged]
      else
        [0,0]
      end
    end

    def handle_layout_click owner,  ev
      if ev.event_type == Gdk::Event::Type::BUTTON2_PRESS
        @note_counter += 1
        x,y =****@layou*****
        create_note(x,y, "Note#{@note_counter}")
      else
        @xp, @yp =****@layou*****
        @wx, @wy = get_note_pointer
        @wx = @xp - @wx
        @wy = @yp - @wy
        Gtk.grab_add(@layout)
      end
    end

    Gtk.init
    w = Window.new
    w.title = 'Layout Example'
    w.set_size_request 500,400
    w.signal_connect('destroy'){Gtk.main_quit}
    w.add @layout = NoteLayout.new
    @note_counter = 0
    @layout.set_events(Gdk::Event::ALL_EVENTS_MASK)
    @layout.signal_connect('button-press-event'){|owner, ev| handle_layout_click owner,  ev  }
    @layout.signal_connect('button-release-event'){
      if @note_being_dragged != nil
        Gtk.grab_remove(@layout)
        nxp, nyp =****@layou*****
        @layout.move(@note_being_dragged, nxp - @wx, nyp - @wy)
        @note_being_dragged.grab_focus
      end
      @note_being_dragged = nil
    }
    w.show_all
    Gtk.main 

  == Author
  Joao Pedrosa - joaopedrosa at yahoo dot com

  == ChangeLog
+ :2004-05-25 Masao
+  Some modified.
  :2004-05-24 Joao Pedrosa
   Initial release

Ruby-GNOME2

[ruby-gnome2-doc-cvs] [Hiki] update - tips_layout_example