giulienk has asked for the wisdom of the Perl Monks concerning the following question:

How can I apply the anti-aliasing offered by Image::Magick upon an image created with GD::Graph?
I tried 
my $image = Image::Magick->new;
my $x = $image->Read('myGDGraphImage.png');
$image->Set(antialias=>'True');
$x = $image->Write('mySupposedToBeAliased.png');

[download]
but it's not working: setting an attribute is obvioulsy not like manipulating the image.
So maybe i'm looking the wrong way and there is anti-aliasing support in GD? Other modules supporting anti-aliasing? Or maybe Image::Magick can do it but i'm not able to make it work?
Thank you.

gkinueliileunikg

Replies are listed 'Best First'.
Re: Image anti-aliasing using GD and Image::Magick
by Masem (Monsignor) on Dec 08, 2001 at 20:20 UTC
    While not knowing the programming logistics behind it, typically in graphics work, you have to apply anti-aliasing as you paint to the image; you cannot take an image and make it anti-alised. (You *could* play with blur and other options to make it appear AA'ed, but this is probably not what you want). So if you drew additional text to the image at this point (after you set the AA property) I'd expect that text to be AA'd, but nothing else on the image.

    -----------------------------------------------------
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[reply]
Re: Image anti-aliasing using GD and Image::Magick
by hsmyers (Canon) on Dec 08, 2001 at 22:36 UTC

    Just glancing at the documentation for IM, setting the attribute is passive. At a guess, you would at least have to reload the image, but more likely, you would have to scale the image—for AA, often you go from a larger image to a smaller image. This creates a kind of 'super' pixel which is filtered to determine the new color value. I noticed that IM has plenty of filters and effects to play with, so there should be some combination that gets you what you are looking for. Try super search here and google looking for AA information. There is lots on the net, this is a big subject (AA, not necessarily IM)

    –hsm

[reply]
      Thank you for your advice.
      I think i can get good results creating a larger image and then scaling it down with something like this: 
      #this is the default example for GD::Graph3D
use GD::Graph::bars3d;
use Image::Magick;

my @data = ( 
       ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"],
       [ 1203,  3500,  3973,  2859,  3012,  3423,  1230]
    );

my $graph = new GD::Graph::bars3d( 800, 600 ); #BIG image

    $graph->set( 
        x_label           => 'Day of the week',
        y_label           => 'Number of hits',
        title             => 'Daily Summary of Web Site',
    );
my $gd = $graph->plot( \@data );

#here the interesting part
my $image=Image::Magick->new(magick=>'png');
$image->BlobToImage($gd->png);
$image->Resize(width=>400, height=>300); #small and anti-aliased one
$image->Write('graph3d.png');

      [download]

      gkinueliileunikg

[reply]
[d/l]

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