Fired during image export (JPEG, PNG, SVG) and direct printing. Allows you to provide alternative text for the grid cell (image export doesn't support HTML in grid cells).
DayPilot.Scheduler.onBeforeCellExport(args);
The "args" object is the same instance that is used in onBeforeCellRender (which is called right before onBeforeCellExport).
Basic HTML to text conversion - replaces line breaks:
dp.onBeforeEventExport = function(args) {
args.text = args.e.client.html().replace("<br>", "\n");
};