From: Victor Reyes <victor.reyes@...>
Date: 2008-04-01T02:19:17+09:00
Subject: Re: Displaying gruff graphs

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Mark, thank you for your answer and time.

Alex, this is exactly what I am looking for. I am trying to do two things at
the same time: Learning Ruby well and second learning to use gruff so I can
use it at work.
I copied your sample code where I incorporated the sample gruff code that I
got from the web. When I run it, a wx frame flashes quickly and end. Some
errors are displayed on the screen.
Would you mind if I send you directly my piece of code? It is very very
simple. It only adds about five (5) lines to your sample code.

Thank you for your help.

Victor

PS: The following are the errors:
C:\$user\vmr\Ruby>ruby rdg00.rb
c:/ruby/lib/ruby/gems/1.8/gems/gruff-0.3.1/lib/gruff/base.rb:465:in `write':
no encode delegate for this image format `C:/DOCUME~1/REYESV~1
:ImageMagickError)
        from c:/ruby/lib/ruby/gems/1.8/gems/gruff-0.3.1/lib/gruff/base.rb:465:in
`write'
        from rdg00.rb:25:in `on_paint'
        from c:/ruby/lib/ruby/gems/1.8/gems/wxruby-1.9.5-i386-mswin32/lib/wx/classes/evthandler.rb:123:in
`call'
        from c:/ruby/lib/ruby/gems/1.8/gems/wxruby-1.9.5-i386-mswin32/lib/wx/classes/evthandler.rb:123:in
`acquire_handler'
        from c:/ruby/lib/ruby/gems/1.8/gems/wxruby-1.9.5-i386-mswin32/lib/wx/classes/window.rb:44:in
`call'
        from c:/ruby/lib/ruby/gems/1.8/gems/wxruby-1.9.5-i386-mswin32/lib/wx/classes/window.rb:44:in
`evt_paint'
        from c:/ruby/lib/ruby/gems/1.8/gems/wxruby-1.9.5-i386-mswin32/lib/wx/classes/app.rb:16:in
`call'
        from c:/ruby/lib/ruby/gems/1.8/gems/wxruby-1.9.5-i386-mswin32/lib/wx/classes/app.rb:16:in
`process_event'
        from c:/ruby/lib/ruby/gems/1.8/gems/wxruby-1.9.5-i386-mswin32/lib/wx/classes/app.rb:16:in
`main_loop'
        from c:/ruby/lib/ruby/gems/1.8/gems/wxruby-1.9.5-i386-mswin32/lib/wx/classes/app.rb:16:in
`run'
        from rdg00.rb:34


On 3/31/08, Alex Fenton <aff28@deleteme.cam.ac.uk> wrote:
>
> Victor Reyes wrote:
>
> > Once a graph is written to disk, g.write("filename.png"), how can it be
> > displayed in Ruby?
> > I would like to re-create the graph and re-displayed often enough to
> give
> > the appearance of "real time"
>
>
> It's not clear whether you meant via a browser or in a desktop app. If
> you want to show it on the desktop, you'll need some sort of GUI toolkit
> to display a window then draw the bitmap in it.
>
> You have a lot of choices: wxRuby, FXRuby, QT/Ruby, Tk, Ruby/GTK etc
> etc. They vary widely in suitability for different platforms, ease of
> installation, features, aesthetics.
>
> I use wxRuby b/c it's easy to install (gem install wxruby) and looks
> good on all the big platforms. A simple 25-line example that would
> regularly redraw an updated graph is below:
>
> hth
> alex
> __
> require 'wx'
> require 'tempfile'
>
> # A frame that draws a regularly updated graph from Gruff every X
> millisecs
> class GruffFrame < Wx::Frame
>    def initialize(refresh_delay = 5000)
>      super(nil, :title => 'Gruff')
>      Wx::Timer.every(refresh_delay) { refresh }
>      evt_paint :on_paint
>    end
>
>    # Writes the gruff graph to a file then reads it back to draw it
>    def on_paint
>      # Set up your graph here
>      graph = Gruff::Lines.new # ....
>      # Write to a tempfile and read back
>      tmp = Tempfile.new('gruff')
>      graph.write(tmp.path)
>      bmp = Wx::Bitmap.new(tmp.path, Wx::BITMAP_TYPE_PNG)
>      # Draw it on the Frame
>      paint do | dc |
>        dc.draw_bitmap(bmp, 0, 0, false)
>      end
>    end
> end
>
> Wx::App.run { GruffFrame.new.show }
>
>

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