Class: TkImageMap::ImageMap

Inherits:
TkCanvas show all
Defined in:
lib/drx/tk/imagemap.rb

Overview

A widget to show an image together with an HTML imagemap.

Instance Method Summary collapse

Methods inherited from TkCanvas

#coords, #raise

Constructor Details

#initialize(parent, *rest) ⇒ ImageMap

Returns a new instance of ImageMap.



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# File 'lib/drx/tk/imagemap.rb', line 41

def initialize(parent, *rest)
  super
  @hover_region = nil
  @active_region = nil
  @hotspots = []
  @image_widget = nil
  @select_command = proc {}
  @double_select_command = proc {}

  # Attach scrolling to middle button.
  canvas.bind('2', proc { |x,y| canvas.scan_mark(x,y) }, '%x %y')
  canvas.bind('B2-Motion', proc { |x,y| canvas.scan_dragto x, y }, '%x %y')

  canvas.pack :expand => true, :fill => 'both'

  ['Motion','Control-Motion'].each { |sequence|
    canvas.bind sequence do |evt|
      x, y = canvas.coords(evt)
      spot = canvas.find('overlapping', x, y, x + 1, y + 1).first
      if spot and spot.cget('tags').include? 'hotspot'
        new_hover_region = spot.hotspot_region
      else
        new_hover_region = nil
      end
      if new_hover_region != @hover_region
        @hover_region[:hover_spot].configure(:state => 'hidden') if @hover_region
        @hover_region = new_hover_region
        @hover_region[:hover_spot].configure(:state => 'disabled') if @hover_region # like 'visible'
        if sequence['Control']
          self.active_region = @hover_region
        end
      end
    end
  }
  canvas.bind 'Button-1' do |evt|
    x, y = canvas.coords(evt)
    spot = canvas.find('overlapping', x, y, x+1, y+1).first
    if spot and spot.cget('tags').include? 'hotspot'
      self.active_region = spot.hotspot_region
    else
      self.active_region = nil
    end
  end
  canvas.bind 'Double-Button-1' do
    @double_select_command.call(active_url) if @active_region
  end
  # Middle button: vertical scrolling.
  canvas.bind 'Button-4' do
    canvas.yview_scroll(-1, 'units')
  end
  canvas.bind 'Button-5' do
    canvas.yview_scroll(1, 'units')
  end
  # Middle button: horizontal scrolling.
  canvas.bind 'Shift-Button-4' do
    canvas.xview_scroll(-1, 'units')
  end
  canvas.bind 'Shift-Button-5' do
    canvas.xview_scroll(1, 'units')
  end
end

Instance Method Details

#active_region=(region) ⇒ Object 



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# File 'lib/drx/tk/imagemap.rb', line 103

def active_region=(region)
  if region != @active_region
    @active_region[:active_spot].configure(:state => 'hidden') if @active_region
    @active_region = region
    @active_region[:active_spot].configure(:state => 'disabled') if @active_region # like 'visible'
    @select_command.call(active_url)
  end
end

#active_url ⇒ Object 



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# File 'lib/drx/tk/imagemap.rb', line 112

def active_url
  @active_region ? @active_region[:url] : nil
end

#active_url=(newurl) ⇒ Object 



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# File 'lib/drx/tk/imagemap.rb', line 116

def active_url=(newurl)
  catch :found do
    @hotspots.each { |region|
      if region[:url] == newurl
        self.active_region = region
        throw :found
      end
    }
    # It was not found:
    self.active_region = nil
  end
end

#canvas ⇒ Object

I’m not yet sure I want ImageMap to be a TkCanvas directly (an alternative would be for it to control an external canvas). So, for future compatibility, I access the canvas through canvas() instead of assuming it’s ‘self’.



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# File 'lib/drx/tk/imagemap.rb', line 37

def canvas
  self
end

#double_select_command(&block) ⇒ Object 



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# File 'lib/drx/tk/imagemap.rb', line 24

def double_select_command &block
  @double_select_command = block
end

#image=(pathname) ⇒ Object 



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# File 'lib/drx/tk/imagemap.rb', line 129

def image=(pathname)
  @image = TkPhotoImage.new :file => pathname
  canvas.configure :scrollregion => [0, 0, @image.width, @image.height]
end

#image_map=(pathname) ⇒ Object

You must call this after image=()



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# File 'lib/drx/tk/imagemap.rb', line 135

def image_map=(pathname)
  # Delete the previous spot widgets and the image widget.
  canvas.find('all').each {|w| w.destroy }
  canvas.xview_moveto(0)
  canvas.yview_moveto(0)

  @hotspots = Utils.parse_imap(pathname)

  #
  # Create the back spots.
  #
  @hotspots.each do |region|
    args = [canvas, *(region[:args])]
    opts = {
      :fill => 'red',
      :tags => ['hotspot']
    }
    back_spot = region[:class].new *(args + [opts])
    # The following won't work, so we have to use define_method instead.
    #def back_spot.hotspot_region
    #   region
    #end
    meta = class << back_spot; self; end
    meta.send :define_method, :hotspot_region do
      region
    end
  end

  @image_widget = TkcImage.new(canvas,0,0, :image => @image, :anchor=> 'nw')

  #
  # Create the hover spots.
  #
  @hotspots.each do |region|
    args = [canvas, *(region[:args])]
    opts = {
      :dash => '. ',
      :width => 5,
      :fill => nil,
      :outline => 'black',
      :state => 'hidden'
    }
    region[:hover_spot] = region[:class].new *(args + [opts])
    opts = {
      :width => 5,
      :fill => nil,
      :outline => 'black',
      :state => 'hidden'
    }
    region[:active_spot] = region[:class].new *(args + [opts])
  end
end

#select_command(&block) ⇒ Object 



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# File 'lib/drx/tk/imagemap.rb', line 20

def select_command &block
  @select_command = block
end

#urls ⇒ Object

Returns all the URLs.



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# File 'lib/drx/tk/imagemap.rb', line 29

def urls
  @hotspots.map { |h| h[:url] }
end