mem_inspect and png

Eric Hodel | Thu, 31 Aug 2006 22:52:00 GMT

Posted in Hacking, Ruby, Software

I'm pleased to announce to new libraries written by members of the Seattle Ruby Brigade, mem_inspect and png!

mem_inspect

mem_inspect is ObjectSpace.each_object on crack. mem_inspect gives you the contents of each slot in Ruby's heap. mem_inspect also includes viewers that let you visualize the contents of Ruby's heap.

To install:

sudo gem install mem_inspect

Then you'll need to build a patched ruby:

ruby_mem_inspect_build

You'll then have a ruby capable of running mem_inspect in mem_inspect_ruby_1_8.

You can make an image with:

mem_inspect_ruby_1_8/ruby_mem_inspect -S ruby_mem_dump

Which will give you a PNG in your current directory named: mem_inspect.PID.TIMESTAMP.png

You'll get an image that looks something like this:

http://flickr.com/photos/drbrain/229482312/

Bigger:

http://flickr.com/photo_zoom.gne?id=229482312&size=o

To dump a PDF any time you want:

require 'meminspect/png_viewer'

MemInspect::PNGViewer.new(1024, 768).draw

You can also dump to an AquaTerm plot window if you have RubyCocoa and AquaTerm installed.

require 'meminspect/aquaterm_viewer'

MemInspect::AquatermViewer.new(1024, 768).draw

png

png is a pure-ruby PNG writing library written by Ryan Davis.

To install:

sudo gem install png

To use:

require 'png'

canvas = PNG::Canvas.new 200, 200

# Set a point to a color
canvas[100, 100] = PNG::Color::Black

# draw an anti-aliased line
canvas.line 50, 50, 100, 50, PNG::Color::Blue

png = PNG.new canvas
png.save 'blah.png'

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