Scheduler

A scheduler is time drawn twice: days across the top, hours down the side, and every event a block sitting in the cell where it actually happens. That second axis is the whole point. A calendar is a month of dates, and it can tell you that the 18th is a Thursday but not that Thursday is booked solid from ten until three. Put the hours down the side and the answer is a shape rather than a list: the gaps are the free time, and they are the same size on screen as they are in the day.

Because the block has a real height, the surface can be operated by pointing at it. An event is moved by dragging it to another cell, lengthened by pulling its lower edge, and made in the first place by dragging out its extent across empty slots, which is drag to create. Nothing else in the interface has to say “10:30” out loud for any of that to work, which is why a scheduler feels less like a form than almost any other component that edits data.

Two pieces of the layout are usually underspecified and always noticed. Above the hours sits an all-day band, because an event with no time cannot be given a height and would otherwise stretch the grid or land at midnight. And two events sharing a slot have to be resolved somehow: side by side at half width each, which stays honest but shrinks as the overlap deepens, or stacked with a “+2 more” once the column runs out of room. A line marking the current time is the third small thing, and it is what makes the view read as now rather than as a plan. Libraries differ here in ways worth reading before building: MUI X calls the whole family a Scheduler and FullCalendar calls this view a time grid.

The word is worth pinning down because the neighbouring names have moved. FullCalendar once called this view “agenda”, then renamed it, and the agenda spelling now belongs to the chronological list instead: see agenda view. In the other direction, scheduler libraries often ship a “timeline” that puts resources (rooms, people, machines) down the side with time running across, which is the shape of a Gantt chart rather than of this. A scheduler crosses days with hours; a Gantt chart crosses tasks with dates.