http://qs321.pair.com?node_id=11112516

Imager::GIF - a handy module for animated GIF processing - is a nice thought, with one semi-working method and problematic documentation (Re^2: Imager::GIF seems broken), that needs some help, as the docs say:

I needed to non-proportionally scale animated GIFs and implemented type=>nonprop in the scale method. Other desirable features include crop, watermark, and sharpening. Please share your mods and methods here.

TODO:

  • https://metacpan.org/pod/distribution/Imager/lib/Imager/Transformations.pod
  • https://metacpan.org/pod/distribution/Imager/lib/Imager/Filters.pod

    Your local file: 

    perl -MImager::GIF -le 'for (keys %INC) { print $INC{$_} if /GIF\.pm/ 
+}'

    [download]
    My scale method: 
    sub scale {
    my ($self, %args) = @_;
    my $ratio = $args{scalefactor} // 1;
    my $qtype = $args{qtype} // 'mixing'; # add qtype support
    
    $self->_mangle(sub {
  
        my $img = shift;
        my $ret = $img->scale(%args, qtype => $qtype);
        my $h = $img->tags(name => 'gif_screen_height');
        my $w = $img->tags(name => 'gif_screen_width');
        
# add non-proportional scaling
        if (
        $args{xpixels} and
        $args{ypixels} and
        $args{type}    and
        $args{type} eq 'nonprop') {
            
            my $xratio
            = defined $args{xpixels}
            ? $args{xpixels} / $w
            : $ratio;
            
            my $yratio
            = defined $args{ypixels}
            ? $args{ypixels} / $w
            : $ratio;

            $ret->settag(name => 'gif_left',
                        value => int($xratio * $img->tags(name => 'gif
+_left')));
            $ret->settag(name => 'gif_top',
                        value => int($yratio * $img->tags(name => 'gif
+_top')));
            $ret->settag(name => 'gif_screen_width',  value => int($xr
+atio * $w));
            $ret->settag(name => 'gif_screen_height', value => int($yr
+atio * $h));
        }
        else {
# proportional scaling, from the original
            unless ($ratio) {
                if (defined $args{xpixels}) {
                    $ratio = $args{xpixels} / $w;
                }
                if (defined $args{ypixels}) {
                    $ratio = $args{ypixels} / $h;
                }
            }
            $ret->settag(name => 'gif_left',
                         value => int($ratio * $img->tags(name => 'gif
+_left')));
            $ret->settag(name => 'gif_top',
                         value => int($ratio * $img->tags(name => 'gif
+_top')));
            $ret->settag(name => 'gif_screen_width',  value => int($ra
+tio * $w));
            $ret->settag(name => 'gif_screen_height', value => int($ra
+tio * $h));
        }
        return $ret;
    });
}

    [download]
    Thank you!

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