Mixed Labeling: Integrating Internal and External Labels

Čmolík L., V. Pavlovec, H. -Y. Wu and M. Nöllenburg, Mixed Labeling: Integrating Internal and External Labels. IEEE Transactions on Visualization and Computer Graphics, 28(4), pages 1848-1861, 2022. DOI: 10.1109/TVCG.2020.3027368

Abstract

In this paper, we present an algorithm capable of mixed labeling of 2D and 3D objects. In mixed labeling, the given objects are labeled with both internal labels placed (at least partially) over the objects and external labels placed in the space around the objects and connected with the labeled objects with straight-line leaders. The proposed algorithm determines the position and type of each label based on the user-specified ambiguity threshold and eliminates overlaps between the labels, as well as between the internal labels and the straight-line leaders of external labels. The algorithm is a screen-space technique; it operates in an image where the 2D objects or projected 3D objects are encoded. In other words, we can use the algorithm whenever we can render the objects to an image, which makes the algorithm fit for use in many domains. The algorithm operates in real-time, giving the results immediately. Finally, we present results from an expert evaluation, in which a professional illustrator has evaluated the label layouts produced with the proposed algorithm.

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Supplementary material

For graphical overview of the first two steps of the proposed algorithm with all the used buffers and for additional results please see the supplementary material.

Acknowledgements

This research has been supported by MEYS of Czechia OP VVV grant No. CZ.02.1.01/0.0/0.0/16 019/0000765 – Research Center for Informatics, Grant Agency of CTU in Prague grant No. SGS19/179/OHK3/3T/13, EU Horizon 2020 MSCA grant No. 747985, and the Austrian Science Fund (FWF) grant P 31119.