Joe,
It's your lucky day. New feature added to the PDL-CVS for reading image
data from scalars. Just pass data=>$var to new(), which will work for
most types. WBMP and GD types can't be recognized from the binary data,
so you'll have to specify type=>'wbmp' or type=>'gd' for those.
-Judd
On Mon, 2007-01-08 at 14:19 -0500, zentara wrote:
> On Mon, 08 Jan 2007 12:45:24 -0600
> Judd Taylor <judd.t@xxxxxxxxxxxxxxxxxx> wrote:
>
> >I'm not so certain it would be that simple... it all depends on the
> >format of the data you're giving me.
> >
> >It would make sense to have a new() that takes a piddle as input, but
> >supporting formats beyond that gets a little tricky. I know of many
> >formats for images in memory, and they're all different. For instance,
> >the PNG in-memory format is totally incomprehensible (which is why I use
> >GD).
> >
> >The PDL::IO::GD lib uses GD's internal gdImage C struct as it's internal
> >format. Only the pointer to that struct is passed to the Perl level.
> >
> >To be honest, it's been a really long time since I used GD::Image for
> >anything. Not being able to get to the data has been a show-stopper for
> >us PDL folks.
> >
> >Give me some more info on your memory format, and I'll see whats up with
> >supporting it.
> >-Judd
>
> Well it's not that important to have that feature, but almost every Perl
> module
> dealing with graphics, now have the ability to read images in/out from/to
> scalar
> strings.
>
> ImageMagick has blobs:
> #!/usr/bin/perl
>
> use warnings;
> use strict;
> use Image::Magick;
> my $imgfile = shift;
> my $image =Image::Magick->new();
> $image->Read($imgfile);
> my $blob = $image->ImageToBlob();
> #and the opposite
> my $output = Image::Magick->new(magick=>'jpg');
> $output->BlobToImage( $blob );
> $output->Resize(geometry=>'160x120'); $output->Write('z.jpg');
>
> ##########################################################
>
> Imager and the Perl GD module have similar methods now for
> reading from perl scalars, they use the -data option or a reference
> to the scalar, like \$inline_image.
>
> Here is a GD example, I get a binary image from the net
> which is in a scalar, and without saving it first as a temp
> file, I load it into GD, where I can manipulate it.
>
> #!/usr/bin/perl -w
> use strict;
> use LWP::Simple;
> use GD;
>
> my $URL = 'http://zentara.net/2uni2.jpg';
> my $content = get($URL) or die $!;
>
> #content now contains a binary string like
> # my $content = `cat image.jpg`
>
> #in regular GD you can read this directly
> #from the scalar
> my $gdimage = new GD::Image($content);
>
> # I was hoping to convert to piddle right here
> # without a temp file
>
> open(GD, ">$0.png") or die;
>
> binmode GD;
>
> print GD $gdimage->png;
>
> close GD;
> __END__
>
>
> So I was hoping that PDL::IO::GD could read in $content,
> as above, as opposed to writing it to a temp file first.
>
> Anyways, the format of the scalar is still png, jpg, gif,
> or whatever, it's just in binary-string form, rather than a disk file.
>
> Thanks for considering this,
> zentara
>
--
____________________________
Judd Taylor
Software Engineer
Orbital Systems, Ltd.
8304 Esters Blvd, Suite 870
Irving, TX 75063-2209
judd.t@xxxxxxxxxxxxxxxxxx
(469) 442-1767 x127
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