path: root/IkiWiki/Plugin/img.pm

#!/usr/bin/perl
# Ikiwiki enhanced image handling plugin
# Christian Mock cm@tahina.priv.at 20061002
package IkiWiki::Plugin::img;

use warnings;
use strict;
use IkiWiki 3.00;

my %imgdefaults;

sub import {
    hook(type => "getsetup", id => "img", call => \&getsetup);
    hook(type => "preprocess", id => "img", call => \&preprocess, scan => 1);
}

sub getsetup () {
    return
        plugin => {
            safe => 1,
            rebuild => undef,
            section => "widget",
        },
        img_allowed_formats => {
            type => "string",
            default => [qw(jpeg png gif svg)],
            description => "Image formats to process (jpeg, png, gif, svg, pdf or 'everything' to accept all)",
            # ImageMagick has had arbitrary code execution flaws,
            # and the whole delegates mechanism is scary from
            # that perspective
            safe => 0,
            rebuild => 0,
        },
}

sub allowed {
    my $format = shift;
    my $allowed = $config{img_allowed_formats};
    $allowed = ['jpeg', 'png', 'gif', 'svg'] unless defined $allowed && @$allowed;

    foreach my $a (@$allowed) {
        return 1 if lc($a) eq $format || lc($a) eq 'everything';
    }

    return 0;
}

sub preprocess (@) {
    my ($image) = $_[0] =~ /$config{wiki_file_regexp}/; # untaint
    my %params=@_;

    if (! defined $image) {
        error("bad image filename");
    }

    if (exists $imgdefaults{$params{page}}) {
        foreach my $key (keys %{$imgdefaults{$params{page}}}) {
            if (! exists $params{$key}) {
                $params{$key}=$imgdefaults{$params{page}}->{$key};
            }
        }
    }

    if (! exists $params{size} || ! length $params{size}) {
        $params{size}='full';
    }

    if ($image eq 'defaults') {
        $imgdefaults{$params{page}} = \%params;
        return '';
    }

    add_link($params{page}, $image);
    add_depends($params{page}, $image);

    # optimisation: detect scan mode, and avoid generating the image
    if (! defined wantarray) {
        return;
    }

    my $file = bestlink($params{page}, $image);
    my $srcfile = srcfile($file, 1);
    if (! length $file || ! defined $srcfile) {
        return htmllink($params{page}, $params{destpage}, $image);
    }

    my $dir = $params{page};
    my $base = IkiWiki::basename($file);
    my $extension;
    my $format;

    if ($base =~ m/\.([a-z0-9]+)$/is) {
        $extension = $1;
    }
    else {
        error gettext("Unable to detect image type from extension");
    }

    # Never interpret well-known file extensions as any other format,
    # in case the wiki configuration unwisely allows attaching
    # arbitrary files named *.jpg, etc.
    my $magic;
    my $offset = 0;
    open(my $in, '<', $srcfile) or error sprintf(gettext("failed to read %s: %s"), $file, $!);
    binmode($in);

    if ($extension =~ m/^(jpeg|jpg)$/is) {
        $format = 'jpeg';
        $magic = "\377\330\377";
    }
    elsif ($extension =~ m/^(png)$/is) {
        $format = 'png';
        $magic = "\211PNG\r\n\032\n";
    }
    elsif ($extension =~ m/^(gif)$/is) {
        $format = 'gif';
        $magic = "GIF8";
    }
    elsif ($extension =~ m/^(svg)$/is) {
        $format = 'svg';
    }
    elsif ($extension =~ m/^(pdf)$/is) {
        $format = 'pdf';
        $magic = "%PDF-";
    }
    else {
        # allow ImageMagick to auto-detect (potentially dangerous)
        $format = '';
    }

    error sprintf(gettext("%s image processing disabled in img_allowed_formats configuration"), $format ? $format : "\"$extension\"") unless allowed($format ? $format : "everything");

    # Try harder to protect ImageMagick from itself
    if (defined $magic) {
        my $content;
        read($in, $content, length $magic) or error sprintf(gettext("failed to read %s: %s"), $file, $!);
        if ($magic ne $content) {
            error sprintf(gettext("\"%s\" does not seem to be a valid %s file"), $file, $format);
        }
    }

    my $ispdf = $base=~s/\.pdf$/.png/i;
    my $pagenumber = exists($params{pagenumber}) ? int($params{pagenumber}) : 0;
    if ($pagenumber != 0) {
        $base = "p$pagenumber-$base";
    }

    my $imglink;
    my $imgdatalink;
    my ($dwidth, $dheight);

    my ($w, $h);
    if ($params{size} ne 'full') {
        ($w, $h) = ($params{size} =~ /^(\d*)x(\d*)$/);
    }

    if ($format eq 'svg') {
        # svg images are not scaled using ImageMagick because the
        # pipeline is complex. Instead, the image size is simply
        # set to the provided values.
        #
        # Aspect ratio will be preserved automatically when
        # only a width or only a height is specified.
        # When both are specified, aspect ratio will not be
        # preserved.
        $imglink = $file;
        $dwidth = $w if length $w;
        $dheight = $h if length $h;
    }
    else {
        eval q{use Image::Magick};
        error gettext("Image::Magick is not installed") if $@;
        my $im = Image::Magick->new();
        my $r = $im->Read("$format:$srcfile\[$pagenumber]");
        error sprintf(gettext("failed to read %s: %s"), $file, $r) if $r;

        if (! defined $im->Get("width") || ! defined $im->Get("height")) {
            error sprintf(gettext("failed to get dimensions of %s"), $file);
        }

        if (! length $w && ! length $h) {
            $dwidth = $im->Get("width");
            $dheight = $im->Get("height");
        } else {
            error sprintf(gettext('wrong size format "%s" (should be WxH)'), $params{size})
                unless (defined $w && defined $h &&
                        (length $w || length $h));

            if ($im->Get("width") == 0 || $im->Get("height") == 0) {
                ($dwidth, $dheight)=(0, 0);
            } elsif (! length $w || (length $h && $im->Get("height")*$w > $h * $im->Get("width"))) {
                # using height because only height is given or ...
                # because original image is more portrait than $w/$h
                # ... slimness of $im > $h/w
                # ... $im->Get("height")/$im->Get("width") > $h/$w
                # ... $im->Get("height")*$w > $h * $im->Get("width")

                $dheight=$h;
                $dwidth=$h / $im->Get("height") * $im->Get("width");
            } else { # (! length $h) or $w is what determines the resized size
                $dwidth=$w;
                $dheight=$w / $im->Get("width") * $im->Get("height");
            }
        }

        if ($dwidth < $im->Get("width") || $ispdf) {
            # resize down, or resize to pixels at all

            my $outfile = "$config{destdir}/$dir/$params{size}-$base";
            $imglink = "$dir/$params{size}-$base";

            will_render($params{page}, $imglink);

            if (-e $outfile && (-M $srcfile >= -M $outfile)) {
                $im = Image::Magick->new;
                $r = $im->Read($outfile);
                error sprintf(gettext("failed to read %s: %s"), $outfile, $r) if $r;
            }
            else {
                $r = $im->Resize(geometry => "${dwidth}x${dheight}");
                error sprintf(gettext("failed to resize: %s"), $r) if $r;

                $im->set($ispdf ? (magick => 'png') : ());
                my @blob = $im->ImageToBlob();
                # don't actually write resized file in preview mode;
                # rely on width and height settings
                if (! $params{preview}) {
                    writefile($imglink, $config{destdir}, $blob[0], 1);
                }
                else {
                    eval q{use MIME::Base64};
                    error($@) if $@;
                    $imgdatalink = "data:image/".$im->Get("magick").";base64,".encode_base64($blob[0]);
                }
            }

            # always get the true size of the resized image (it could be
            # that imagemagick did its calculations differently)
            $dwidth  = $im->Get("width");
            $dheight = $im->Get("height");
        } else {
            $imglink = $file;
        }

        if (! defined($dwidth) || ! defined($dheight)) {
            error sprintf(gettext("failed to determine size of image %s"), $file)
        }
    }

    my ($fileurl, $imgurl);
    my $urltobase = $params{preview} ? undef : $params{destpage};
    $fileurl=urlto($file, $urltobase);
    $imgurl=$imgdatalink ? $imgdatalink : urlto($imglink, $urltobase);

    if (! exists $params{class}) {
        $params{class}="img";
    }

    my $attrs='';
    foreach my $attr (qw{alt title class id hspace vspace}) {
        if (exists $params{$attr}) {
            $attrs.=" $attr=\"$params{$attr}\"";
        }
    }
    
    my $imgtag='<img src="'.$imgurl.'"';
    $imgtag.=' width="'.$dwidth.'"' if defined $dwidth;
    $imgtag.=' height="'.$dheight.'"' if defined $dheight;
    $imgtag.= $attrs.
        (exists $params{align} && ! exists $params{caption} ? ' align="'.$params{align}.'"' : '').
        ' />';

    my $link;
    if (! defined $params{link}) {
        $link=$fileurl;
    }
    elsif ($params{link} =~ /^\w+:\/\//) {
        $link=$params{link};
    }

    if (defined $link) {
        $imgtag='<a href="'.$link.'">'.$imgtag.'</a>';
    }
    else {
        my $b = bestlink($params{page}, $params{link});
    
        if (length $b) {
            add_depends($params{page}, $b, deptype("presence"));
            $imgtag=htmllink($params{page}, $params{destpage},
                $params{link}, linktext => $imgtag,
                noimageinline => 1,
            );
        }
    }

    if (exists $params{caption}) {
        return '<table class="img'.
            (exists $params{align} ? " align-$params{align}" : "").
            '">'.
            '<caption>'.$params{caption}.'</caption>'.
            '<tr><td>'.$imgtag.'</td></tr>'.
            '</table>';
    }
    else {
        return $imgtag;
    }
}

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