ImgPacker : a desktop photo collage creator

Abstract

Photo collages are a popular way of displaying a set of images or photographs in various media, such as presentations, screensavers, and framed print-outs. One such class of these collages, which is the subject of generation in this report, have rectangular images or photographs packed together in a non-grid manner without overlaps or gaps. These collages can be quite difficult to generate by hand, as they typically require a large number of trials, or otherwise lengthy mathematical

calculations in order to obtain even one valid collage layout.

This report details the design and development of a free and open source collage authoring application for the GNU/Linux desktop, dubbed “ImgPacker Collage Creator,” that supports automated collage generation and provides support for low-level, manual customization of the collage layout through a WYSIWYG interface that allows a user to drag and drop individual images or a group of images from one location to another on the collage.

As part of the implementation of the ImgPacker Collage Creator, this report also defines and discusses the problem of generating collage layouts of photos that do not have overlaps or gaps, and a proposed solution for this problem in the form of the Pairwise Combinator algorithm. This algorithm generates collage layouts iteratively by combining pairs of images either horizontally or vertically into sub-collages until only a single sub-collage remains, which is then taken as the final collage. A mechanism for manipulating the resultant collage layout is also discussed.