From: Robert Klemme <shortcutter@...>
Date: 2008-06-15T21:59:20+09:00
Subject: Re: Binary string packing/unpacking issues

On 15.06.2008 12:00, Lucas L. wrote:
> Robert Klemme wrote:
>> It's the bitwise OR operator.
> I don't really know why he uses it though.
> 
> Can you post what "p
>> your_pixbuf.pixels" and "p your_pixbuf.pixels.class" print?
> 
> Now we're getting somewhere. I was using puts to print pixels, and all I 
> got was a bunch of question marks. p returns a massive String 
> (pixels.class shows String). The string itself is uncompressed pixel 
> data, a byte per channel of RGBA. The output is a massive string of 
> "\000\000\000\000\000\000\000\000..." with "\377" where a pixel is 
> drawn, which I'm assumming is 0xFF in the alpha channel (why is \377 
> 0xFF?).
> 
> However, when I tried
>> pixels[pixels.length-1] = '\377'
>> p pixels
> There was no change.

irb#1(main):006:0> "\377"
=> "\377"
irb#1(main):007:0> "\377".length
=> 1
irb#1(main):008:0> '\377'
=> "\\377"
irb#1(main):009:0> '\377'.length
=> 4
irb#1(main):010:0>

Notice something?

I agree with Paul, you have trouble with the basics.  If you try things 
out on a smaller scale in IRB you'll probably see more easily how 
everything works.

Kind regards

	robert