show resized img in preview using data: urls

in analogy to sparklines, this renders scaled imgs to
data:img/...;base64,... urls in preview mode.

if the image is already present on the server (eg because it was not
just inserted), the already rendered image is referenced instead.

diff --git a/IkiWiki/Plugin/img.pm b/IkiWiki/Plugin/img.pm
index 1ab753352e2e28b65430dfd0cf574efc94dcf809..54c13d06919e0858442758d8fec09eb34bf0f0c3 100644 (file)
--- a/IkiWiki/Plugin/img.pm
+++ b/IkiWiki/Plugin/img.pm
@@ -75,6 +75,7 @@ sub preprocess (@) {
        error gettext("Image::Magick is not installed") if $@;
        my $im = Image::Magick->new();
        my $imglink;
+       my $imgdatalink;
        my $r = $im->Read("$srcfile\[$pagenumber]");
        error sprintf(gettext("failed to read %s: %s"), $file, $r) if $r;
        
@@ -123,15 +124,17 @@ sub preprocess (@) {
                        $r = $im->Resize(geometry => "${dwidth}x${dheight}");
                        error sprintf(gettext("failed to resize: %s"), $r) if $r;
 
+                       $im->set(($issvg || $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}) {
-                               $im->set(($issvg || $ispdf) ? (magick => 'png') : ());
-                               my @blob = $im->ImageToBlob();
                                writefile($imglink, $config{destdir}, $blob[0], 1);
                        }
                        else {
-                               $imglink = $file;
+                               eval q{use MIME::Base64};
+                               error($@) if $@;
+                               $imgdatalink = "data:image/".$im->Get("magick").";base64,".encode_base64($blob[0]);
                        }
                }
 
@@ -148,14 +151,9 @@ sub preprocess (@) {
        }
 
        my ($fileurl, $imgurl);
-       if (! $params{preview}) {
-               $fileurl=urlto($file, $params{destpage});
-               $imgurl=urlto($imglink, $params{destpage});
-       }
-       else {
-               $fileurl=urlto($file);
-               $imgurl=urlto($imglink);
-       }
+       my $urltobase = $params{preview} ? undef : $params{destpage};
+       $fileurl=urlto($file, $urltobase);
+       $imgurl=$imgdatalink ? $imgdatalink : urlto($imglink, $urltobase);
 
        if (! exists $params{class}) {
                $params{class}="img";