fxruby users - Nov 2006 - Getting fewer paints per second than I expected

I''ve got a program that puts 20 text labels in the main window.  Each
label updates itself to a global counter on SEL_UPDATE.  The counter
increments 10 times a second.

To my surprise, the labels skip counter updates.  I expected to see
each label painting a new timer value 10 times per second.  Instead,
each label paints about 3 times per second.  CPU is about 100% idle
when the program is running.

Have I made a newbie mistake?  Is this a question for the regular Fox
list?

Fox 1.4.34, FXRuby 1.4.7, Debian testing.

Program follows.

#!/usr/bin/ruby1.8

require ''fox14''

include Fox

class Main

  def initialize
    @i = 0
  end

  def run
    @app = FXApp.new
    main = FXMainWindow.new(@app, File.basename(__FILE__))
    FXButton.new(main, "&Quit") do |button|
      button.layoutHints = LAYOUT_CENTER_X
      button.connect(SEL_COMMAND) do
        exit
      end
    end
    20.times do
      FXLabel.new(main, format_count) do |label|
        label.connect(SEL_UPDATE) do
          label.text = format_count
        end
      end
    end
    main.show(PLACEMENT_SCREEN)
    start_timer
    @app.create
    @app.run
  end

  private

  def format_count
    "%04d" % @i
  end

  def start_timer
    @app.addTimeout(100, method(:timer))
  end

  def timer(sender, sel, data)
    @i += 1
    start_timer
  end

end

Main.new.run if $0 == __FILE__

Wayne Conrad wrote:
> I''ve got a program that puts 20 text labels in the main window. 
Each
> label updates itself to a global counter on SEL_UPDATE.  The counter
> increments 10 times a second.
> 
> To my surprise, the labels skip counter updates.  I expected to see
> each label painting a new timer value 10 times per second.  Instead,
> each label paints about 3 times per second.  CPU is about 100% idle
> when the program is running.
> 
> Have I made a newbie mistake?  Is this a question for the regular Fox
> list?
I verified your observations with fox16 (fxruby): updates skip and cpu < 
   1%. In addition I checked that the timer is really called 10 times 
per second (it turns out to be between 9 and 10 times per second, 
actually, probably due to the time it takes to re-register the timer).

It may be that using SEL_UPDATE works better in pure fox than in fxruby, 
but in my experience it''s better to take control of the updates
yourself
if you want them done promptly.  You can do this by setting up an 
observer relationship and using that to set the label text when the 
variable changes.

This is part of the reason I wrote the observable[1] and foxtails[2] 
libraries. Here''s a modification of your code that updates about 10 
times per second. I had to use a text field in this example instead of a 
label because I had never thought of making label text connect to a 
variable, but it would not be hard to do. It still runs with <1% cpu, 
though probably a bit more than using SEL_UPDATE. FoxTails won''t scale 
up to huge numbers of widgets as well as pure fox, of course, because 
(a) it has an extra layer of ruby code on top of fxruby and (b) is it 
eager rather than lazy about updates. (I feel that the laziness of 
updates in fxruby, especially menu items, is a serious problem.)

   require ''foxtails''

   include Fox
   include FoxTails

   class Main
     extend Observable

     observable :i

     def initialize
       self.i = 0
     end

     def run
       @app = FXApp.new
       main = FXMainWindow.new(@app, File.basename(__FILE__))
       FXButton.new(main, "&Quit") do |button|
         button.layoutHints = LAYOUT_CENTER_X
         button.connect(SEL_COMMAND) do
           exit
         end
       end
       20.times do
         FTTextField.new(main, 10, self, :i)
       end
       main.show(PLACEMENT_SCREEN)
       start_timer
       @app.create
       @app.run
     end

     private

     def start_timer
       @app.addTimeout(100, method(:timer))
     end

     def timer(sender, sel, data)
       self.i += 1
       start_timer
     end

   end

   Main.new.run if $0 == __FILE__

That example didn''t do any formatting, but there is a #field method
that
lets you use various %-escapes to do formatting and also to line things 
up using a FXMartix, perform validation, group radio buttons, add check 
buttons, and so on. These are all connected (in both directions) to ruby 
attrs using the observable mechanism.

In this case, just add your fields using the following code instead of 
the above:

       main.extend FTField
         # normally, you define a window class and include FTField

       20.times do
         main.field "current value is %04d", [self, :i]
       end

The static text "current value os" is displayed as a label, and the 
dynamic text is displayed in a text field (but it could be a label with 
a little work).

Check out foxtails/examples/fields.rb for more.

[1] http://raa.ruby-lang.org/project/observable/
[2] http://raa.ruby-lang.org/project/foxtails/

-- 
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407

Joel VanderWerf wrote:
...
> That example didn''t do any formatting, but there is a #field
method that
> lets you use various %-escapes to do formatting and also to line things 
> up using a FXMartix, perform validation, group radio buttons, add check 
> buttons, and so on. These are all connected (in both directions) to ruby 
> attrs using the observable mechanism.
...
> [1] http://raa.ruby-lang.org/project/observable/
> [2] http://raa.ruby-lang.org/project/foxtails/
Sourceforge seems to be down so just for the heck of it here is another 
example (going a bit OT) of fields with the matrix, validation, 
radio/check, and observable features.

The output of the program, after entering data as shown in the attached 
PNG, is as follows:

$ ruby ship-fields.rb
[#<Ship foo, sailboat, (1.0,2.0), enabled=false>, #<Ship bar,
speedboat,
(3.0,4.0), enabled=true>]

The full program is attached, but this is the heart of it:

matrix = FXMatrix.new(self, 8,
   MATRIX_BY_COLUMNS|FRAME_THICK|LAYOUT_FILL_X)

# The %| character separates fields into different cells of the matrix.
field(matrix,
   " %| name %| x %| y %| speedboat %| sailboat %| steamer %|
enabled")
   # this just adds some header labels

ships = [Ship.new, Ship.new]
ships.each_with_index do |ship, i|
   f = field(matrix, "#{i} %| %s %| %6.2f %| %6.2f %| %r %| %r %| %r %|
%v",
     # %r is radio, %v is check
     [ship, :name],
     [ship, :x],
     [ship, :y],
     [[ship, :kind], "speedboat"],
     [[ship, :kind], "sailboat"],
     [[ship, :kind], "steamer"],
     [ship, :enabled]
   )
   f.valid([ship, :x]) {|x| x >= 0 and x < 100}
   f.valid([ship, :y]) {|y| y >= 0 and y < 100}

-- 
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407
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Joel,

Thanks for the thoughtful replies.  I likely won''t be able to give
them any real attention until the weekend, but wanted to reply now so
you knew they were appreciated.

        Wayne Conrad