Don't forget the cursor.md

Don't forget the cursor

The cursor displayed on the screen gives contextual information to the user about a possible or current action. This is why this interface element should not be overlooked.

You might use this technique to provide visual feedback about what actions the user can take with the mouse. For example, you might display one of the resize cursors whenever the mouse moves over a portion of your view that acts as a custom resizing handle. To set this up, you'll use the command SET CURSOR that allow to change the displayed cursor.

📌 As the effect of this command can be cancelled at any time by a system request for a display update, it is recommended to use it during the On mouse move event. And conversely, if there is no request for a redraw, the cursor may not be reset.

So, the best practice is to set the cursor at the On Mouse Enter and On Mouse Move events, and to remember to restore the standard mouse cursor at the On Mouse Leave event. Like this for example:

$e:=FORM Event

If ($e.code=On Mouse Enter)\
	 | ($e.code=On Mouse Move)
	
	SET CURSOR($id)
	
Else 
	
	SET CURSOR
	
End if 

Note: Cursor availability and appearance may vary depending on the operating system.

Demo

The testCursors project allows you to explore the system cursors available on your platform.

The cursors

The following table shows and describes the avalaible system cursors and indicates the id to pass in the cursor parameter.

macOS		4D ID	Name
	The pointing-hand cursor	9000	pointingHandCursor
	The open-hand cursor	9013	openHandCursor
	The closed-hand cursor	9014	closedHandCursor
	The contextual menu cursor	9015	contextualMenuCursor
	The drag copy cursor	9016	dragCopyCursor
	The not allowed cursor	9019	notAllowedCursor
	The I-beam cursor for indicating insertion points	1	IBeamCursor
	The arrow cursor	355	pointerCursor
	The arrow oriented to right cursor	355	pointerToRightCursor
	The cross-hair cursor	2	crosshairCursor
	The drag link cursor	9017	dragLinkCursor
	The help cursor	9018	helpCursor
	The zoom out cursor	559	zoomOutCursor
	The zoom in cursor	560	zoomInCursor
	The move cursor	9001	moveCursor
	The horizontal resize cursor	9003	horizontalResizeCursor
	The vertical resize cursor	9004	verticalResizeCursor
	The resize top-left-bottom-right cursor	9005	resizeNorthWestSouthEastCursor
	The resize bottom-left-top-right cursor	9006	resizeNorthEastSouthWestCursor
	The resize-left-and-right cursor	9021	resizeleftrightCursor
	The resize-up-and-down cursor	9009	resizeUpDownCursor
	The vertical split cursor	9010	verticalSplitCursor
	The horizontal split cursor	9011	horizontalSplitCursor