NAME

Graphics::DZI::Overlay - DeepZoom Image Pyramid, Sparse Images

SYNOPSIS

  # build some overlays first
  use Graphics::DZI::Overlay;
  my $o1 = new Graphics::DZI::Overlay (image => ...,       # what is the image?
                                       x => 1000, y=>1000, # where on the canvas?
                                       squeeze => 64);     # how much smaller than the canvas?
  my $o2 = new Graphics::DZI::Overlay (image => ...,       # what is the image?
                                       x => 2000, y=>2000, # where on the canvas?
                                       squeeze => 32);     # how much smaller than the canvas?
  # then add the overlay over the canvas
  use Graphics::DZI::Files;
  my $dzi = new Graphics::DZI::Files (image    => $image,
                                      overlap  => 4,
                                      tilesize => 512,
                                      format   => 'png',
                                      overlays => [ $o1, $o2],
                                      path     => $path . 'xxx_files/',
                                      prefix   => 'xxx',
                                      );
   # normal DZI generation
   write_file ($path . 'xxx.xml', $dzi->descriptor);
   $dzi->iterate ();

DESCRIPTION

This package can hold one overlay image, together with a coordinate and a factor how much this images is smaller than the canvas onto which the image is to be put.

INTERFACE

Constructor

It expects the following fields:

image: (required)

Image::Magick object.

x,y: (integers, no default)

Coordinates of the top-left corner of the above image on the canvas

squeeze: (integers, no default)

A factor how much the image should be made smaller, relative to the canvas. I use a power of two to avoid that the canvas is a bit fuzzy.

Methods

halfsize

Makes the overlay smaller by 2. This will be called by the DZI algorithm.

crop

Gets a tile off the overlay.

AUTHOR

Robert Barta, <drrho at cpan.org>

COPYRIGHT & LICENSE

Copyright 2010 Robert Barta, all rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.