in reply to Loading PNG in Perl?

I've written code that generated PNG files by hand. Reading a PNG file isn't much harder. Both GD and ImageMagick do this quite nicely. There is a pureperl solution on CPAN, but I don't remember what it is. I found it a year ago when I was doing this, but it wasn't fast enough for my specialized use. (Turned out that my hand-tuned code was faster for my very specialized use than general purpose C code.)
My criteria for good software:
  1. Does it work?
  2. Can someone else come in, make a change, and be reasonably certain no bugs were introduced?

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Re^2: Loading PNG in Perl?
by Xenofur (Monk) on Jul 31, 2008 at 03:12 UTC
    As mentioned above: GD seems to be for creating only. ImageMagick might do it, but i'm really leery of using such a huge package, since i need to include all the necessary dlls and such in the package of the project i'm working on.

    Speed is not a matter though.
[reply]
      Oh? GD's docs are horrid, so I can see why you missed the following: 
      my $image = GD::Image->newFromPng($filename);

my ($height, $width) = $image->getBounds;

foreach my $x ( 0 .. $width ) {
    foreach my $y ( 0 .. $height ) {
        my ($index) = $image->getPixel($x,$y);
        my ($r,$g,$b) = $image->rgb($index);
        print "($x,$y) -> ($r,$g,$b)\n";
    }
}

      [download]
      That will print out the RGB value for every XY coordinate, row-first. There's a ton of other information you can extract. You just have to spend a few hours reading ALL the docs. It's well worth the effort.
      My criteria for good software:
      1. Does it work?
      2. Can someone else come in, make a change, and be reasonably certain no bugs were introduced?
[reply]
[d/l]

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