From: michael libby <x@...>
Date: 2002-06-07T22:02:16+09:00
Subject: Local works, Instance fails

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I have written a TkSlide widget which essentially incorporates a conversion 
routine (using ImageMagick's convert tool) to get around the limitation of 
TkPhotoImage needing either GIF or PPM images.

As you can see I set up a temporary pathname for the PPM file created by 
convert. What's odd is that in the TkSlide#show method, if I use the 
instance variable @temp_file I don't get an image, but if I assign it to a 
local variable temp_file I do get an image.

Any thoughts? (And any notes on any place I can make my code better/more 
idiomatic would also be appreciated as well...)

Thanks,
- -michael

- ------------------------------------------------------------
class TkSlide < TkLabel

  def initialize(root, *args)
    @root = root

    #name for temp files
    @temp_file = 'temp_pic_' + $$.to_s + '_' +
                 rand(100000).to_i.to_s + '.ppm'
    p "Temp file will be #{@temp_file}" if DEBUG

    argh = args[0] || {}
    @width = argh['width'] || @root.maxsize[0]
    @height = argh['height'] || @root.maxsize[1]

    super(@root, argh)
  end

  def show(pic_path)
    @image.delete if @image #or suffer a memory leak
    begin
      #make sure file still exists
      if !FileTest.exists?(pic_path)
	p "#{pic_path} not found, aborting."
	exit
      end
      
      #convert to PPM and resize
`#{CONVERT} -geometry #{@width}x#{@height} "#{pic_path}" ppm:#{@temp_file}`
      p "#{pic_path} converted" if DEBUG
      
      temp_file = @temp_file #for some reason @temp_file won't work in the 
      @image = TkPhotoImage.new{file temp_file} #image.new command!!
    rescue
      p "Faulty image: #{$!}"
      exit
    end
    self.configure('image'=>@image)

    #delete temp file immediately after use
    File.delete(temp_file)
  end
end 
- -- 
 ______Michael_C_Libby__{_x_(at)_ichimunki_(dot)_com_}______
|           my website: http://www.ichimunki.com/           | 
|____ public key at http://www.ichimunki.com/public.key ____|

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