From: ces.fci.junk@...
Date: 2005-11-14T15:07:16+09:00
Subject: RMagick 1.9.3: examples/histogram.rb - erro

Trying to run the histogram.rb ~/$myimage produces the following error:

Creating b194000514_7064_Histogram.miffhistogram.rb:180:in `histogram':
undefined method `+' for nil:NilClass (NoMethodError)
        from histogram.rb:179:in `each'
        from histogram.rb:179:in `histogram'
        from histogram.rb:177:in `times'
        from histogram.rb:177:in `histogram'
        from histogram.rb:280

For the moment commenting these lines will let it run and output a
viewable miff (beginning at line 180):
                    #red[pixel.red] += 1
                    #green[pixel.green] += 1
                    #blue[pixel.blue] += 1

                    # Only count opacity channel if some pixels are not
opaque.
                    if !opaque?
                        alpha[pixel.opacity] += 1
                    end
                    v = pixel_intensity(pixel)
                    #int[v] += 1


Potentially relevent (or not relevent) information:
Ruby 1.8.2
ImageMagick 6.1.9
Linux 2.6.10

The other examples appear to run without issue.
I am also relatively new to Ruby if that matters.

I tried adding these in the appropiate locations (figured it may have
had problems adding to nil):
red[pixel.red]     = 0 if red[pixel.red].nil?
blue[pixel.blue]   = 0 if blue[pixel.blue].nil?
green[pixel.green] = 0 if green[pixel.green].nil?
#...
alpha[pixel.opacity] = 0 if alpha[pixel.opacity].nil?
#...
int[v]  = 0 if int[v].nil?

The result is another error, but I am not sure how to get around it:
Creating b194000514_7064_Histogram.miff.histogram.rb:5:in `max':
undefined method `<=>' for nil:NilClass (NoMethodError)
        from histogram.rb:208:in `each'
        from histogram.rb:208:in `max'
        from histogram.rb:208:in `histogram'
        from histogram.rb:292

any thoughts on the matter?

Clayton