Input value name. For example, if the value is "plot_brush", then the coordinates will be available as input$plot_brush. Multiple imageOutput/plotOutput calls may share the same id value; brushing one image or plot will cause any other brushes with the same id to disappear.

Fill color of the brush. If 'auto', it derives from the link color of the plot's HTML container (if thematic is enabled, and accent is a non-'auto' value, that color is used instead).

Outline color of the brush. If 'auto', it derives from the foreground color of the plot's HTML container (if thematic is enabled, and fg is a non-'auto' value, that color is used instead).

Opacity of the brush

How long to delay (in milliseconds) when debouncing or throttling, before sending the brush data to the server.

The type of algorithm for limiting the number of brush events. Use "throttle" to limit the number of brush events to one every delay milliseconds. Use "debounce" to suspend events while the cursor is moving, and wait until the cursor has been at rest for delay milliseconds before sending an event.

Should the brush area be clipped to the plotting area? If FALSE, then the user will be able to brush outside the plotting area, as long as it is still inside the image.

The direction for brushing. If "xy", the brush can be drawn and moved in both x and y directions. If "x", or "y", the brush wil work horizontally or vertically.

When a new image is sent to the browser (via renderImage()), should the brush be reset? The default, FALSE, is useful if you want to update the plot while keeping the brush. Using TRUE is useful if you want to clear the brush whenever the plot is updated.