GazePlotter: An open-source solution for the automatic generation of scarf plots from eye-tracking data

Eye-tracking is widely used to study perception, learning, and decision-making, yet visualising temporally structured gaze behaviour remains challenging. Scarf plots (also known as sequence charts) help illustrate when and where participants focus attention, but existing tools are often proprietary, static, or require programming expertise. GazePlotter is an open-source, browser-based application designed to lower these barriers. GazePlotter automatically processes raw exports from six eye-tracking software tools, including Tobii Pro Lab and GazePoint Analysis, and generates interactive, customisable scarf plots. It supports dynamic areas of interest (AOIs), multiple timeline modes (absolute, relative, ordinal), and enables side-by-side comparisons across participants, groups, or stimuli. Complementary visualisations-such as bar charts and transition matrices-can be combined within interactive dashboards. The application runs entirely in the browser (available at https://gazeplotter.com ), preserving data privacy and requiring no installation or registration. Its data pipeline-from import through parsing, AOI aggregation, and export-was validated against proprietary software outputs, with high agreement across key metrics. Parsing is memory-efficient and tested on multi-gigabyte datasets, with consistent functionality across Chrome, Firefox, Safari, and Edge. A task-based usability evaluation demonstrated successful task completion and positive perceived pragmatic and hedonic quality among participants with prior experience in eye-tracking methodology. By enabling non-programmers to create exploratory visualisations directly from raw exports, GazePlotter makes temporally structured gaze data accessible for reproducible, shareable visual analysis. Beyond eye-tracking, the same workflow generalises to any temporally ordered categorical sequence from a compatible CSV input.