SystemCursor (wrapper class for SDL_Cursor)

[nerobotParticipant]

This class allow us to change system app cursor.

Profit: all raw SDL_ structures are hidden / incapsulated here.

One use case is – If you want to change cursor when mouse enter your view, and restore when mouse leave.

To do that, you need to override OnMouseEvent (or OnContentMouseEvent):

Monkey

Protected Method OnContentMouseEvent( event:MouseEvent ) Override Select event.Type Case EventType.MouseEnter SystemCursor.Store( Self ) SystemCursor.Set( SystemCursor.Kind.Beam ) Case EventType.MouseLeave SystemCursor.Restore( Self ) End Super.OnContentMouseEvent( event ) End

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Protected   Method OnContentMouseEvent( event:MouseEvent ) Override   Select event.Type   Case EventType.MouseEnter   SystemCursor.Store( Self ) SystemCursor.Set( SystemCursor.Kind.Beam )   Case EventType.MouseLeave   SystemCursor.Restore( Self )   End   Super.OnContentMouseEvent( event )   End

Available cursors:

• Arrow
• Beam
• Wait
• WaitArrow
• Hand
• No
• CrossHair,
• SizeNWSE, SizeNESW, SizeWE, SizeNS, SizeAll

Source code:

Monkey

Using sdl2.. Class SystemCursor Enum Kind Arrow,Beam,Wait,WaitArrow,Hand,No,CrossHair, SizeNWSE,SizeNESW,SizeWE,SizeNS,SizeAll End Function Set( cursor:Kind ) Local c:=_cursors[cursor] If Not c c=Create( cursor ) _cursors[cursor]=c End SDL_SetCursor( c ) End Function Store( owner:Object ) _stored[owner]=SDL_GetCursor() End Function Restore( owner:Object ) Local c:=_stored[owner] If c SDL_SetCursor( c ) _stored.Remove( owner ) Endif End Private Global _cursors:=New Map<Kind,SDL_Cursor Ptr> Global _stored:=New Map<Object,SDL_Cursor Ptr> Function Create:SDL_Cursor Ptr( cursor:Kind ) Local cur:SDL_SystemCursor Select cursor Case Kind.Arrow cur=SDL_SYSTEM_CURSOR_ARROW Case Kind.Beam cur=SDL_SYSTEM_CURSOR_IBEAM Case Kind.Wait cur=SDL_SYSTEM_CURSOR_WAIT Case Kind.CrossHair cur=SDL_SYSTEM_CURSOR_CROSSHAIR Case Kind.WaitArrow cur=SDL_SYSTEM_CURSOR_WAITARROW Case Kind.No cur=SDL_SYSTEM_CURSOR_NO Case Kind.Hand cur=SDL_SYSTEM_CURSOR_HAND Case Kind.SizeNWSE cur=SDL_SYSTEM_CURSOR_SIZENWSE Case Kind.SizeNESW cur=SDL_SYSTEM_CURSOR_SIZENESW Case Kind.SizeWE cur=SDL_SYSTEM_CURSOR_SIZEWE Case Kind.SizeNS cur=SDL_SYSTEM_CURSOR_SIZENS Case Kind.SizeAll cur=SDL_SYSTEM_CURSOR_SIZEALL End Return SDL_CreateSystemCursor( cur ) End End

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Using sdl2..   Class SystemCursor Enum Kind Arrow,Beam,Wait,WaitArrow,Hand,No,CrossHair, SizeNWSE,SizeNESW,SizeWE,SizeNS,SizeAll End Function Set( cursor:Kind ) Local c:=_cursors[cursor] If Not c c=Create( cursor ) _cursors[cursor]=c End SDL_SetCursor( c ) End Function Store( owner:Object ) _stored[owner]=SDL_GetCursor() End Function Restore( owner:Object ) Local c:=_stored[owner] If c SDL_SetCursor( c ) _stored.Remove( owner ) Endif End Private Global _cursors:=New Map<Kind,SDL_Cursor Ptr> Global _stored:=New Map<Object,SDL_Cursor Ptr> Function Create:SDL_Cursor Ptr( cursor:Kind ) Local cur:SDL_SystemCursor Select cursor Case Kind.Arrow cur=SDL_SYSTEM_CURSOR_ARROW Case Kind.Beam cur=SDL_SYSTEM_CURSOR_IBEAM Case Kind.Wait cur=SDL_SYSTEM_CURSOR_WAIT Case Kind.CrossHair cur=SDL_SYSTEM_CURSOR_CROSSHAIR Case Kind.WaitArrow cur=SDL_SYSTEM_CURSOR_WAITARROW Case Kind.No cur=SDL_SYSTEM_CURSOR_NO Case Kind.Hand cur=SDL_SYSTEM_CURSOR_HAND Case Kind.SizeNWSE cur=SDL_SYSTEM_CURSOR_SIZENWSE Case Kind.SizeNESW cur=SDL_SYSTEM_CURSOR_SIZENESW Case Kind.SizeWE cur=SDL_SYSTEM_CURSOR_SIZEWE Case Kind.SizeNS cur=SDL_SYSTEM_CURSOR_SIZENS Case Kind.SizeAll cur=SDL_SYSTEM_CURSOR_SIZEALL End Return SDL_CreateSystemCursor( cur ) End End

[AdamStrangeParticipant]

Brilliant work.

Here’s a proper class version of the above for you as well:

Monkey

'for dealing with the cursor we need sdl Using sdl2.. Enum Kind Arrow, Beam, Wait, WaitArrow, Hand, No, CrossHair, SizeNWSE, SizeNESW, SizeWE, SizeNS, SizeAll End const CURSOR_ARROW:Kind = Kind.Arrow const CURSOR_BEAM:Kind = Kind.Beam const CURSOR_WAIT:Kind = Kind.Wait const CURSOR_WAITARROW:Kind = Kind.WaitArrow const CURSOR_HAND:Kind = Kind.Hand const CURSOR_NO:Kind = Kind.No const CURSOR_CROSSHAIR:Kind = Kind.CrossHair const CURSOR_SIZENWSE:Kind = Kind.SizeNWSE const CURSOR_SIZENESW:Kind = Kind.SizeNESW const CURSOR_SIZEWE:Kind = Kind.SizeWE const CURSOR_SIZENS:Kind = Kind.SizeNS const CURSOR_SIZEEW:Kind = Kind.SizeWE const CURSOR_SIZESN:Kind = Kind.SizeNS const CURSOR_SIZEALL:Kind = Kind.SizeAll Class SystemCursor method New() _cursors = New Map<Kind, SDL_Cursor Ptr> End method method Set( cursor:Kind ) Local c:SDL_Cursor ptr = _cursors[cursor] If Not c then c = Create( cursor ) _cursors[cursor] = c End SDL_SetCursor( c ) End method method Restore() Set( CURSOR_ARROW ) End Private field _cursors:Map<Kind, SDL_Cursor Ptr> method Create:SDL_Cursor Ptr( cursor:Kind ) Local cur:SDL_SystemCursor Select cursor Case Kind.Arrow cur = SDL_SYSTEM_CURSOR_ARROW Case Kind.Beam cur = SDL_SYSTEM_CURSOR_IBEAM Case Kind.Wait cur = SDL_SYSTEM_CURSOR_WAIT Case Kind.CrossHair cur = SDL_SYSTEM_CURSOR_CROSSHAIR Case Kind.WaitArrow cur = SDL_SYSTEM_CURSOR_WAITARROW Case Kind.No cur = SDL_SYSTEM_CURSOR_NO Case Kind.Hand cur = SDL_SYSTEM_CURSOR_HAND Case Kind.SizeNWSE cur = SDL_SYSTEM_CURSOR_SIZENWSE Case Kind.SizeNESW cur = SDL_SYSTEM_CURSOR_SIZENESW Case Kind.SizeWE cur = SDL_SYSTEM_CURSOR_SIZEWE Case Kind.SizeNS cur = SDL_SYSTEM_CURSOR_SIZENS Case Kind.SizeAll cur = SDL_SYSTEM_CURSOR_SIZEALL End Select Return SDL_CreateSystemCursor( cur ) End method End

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'for dealing with the cursor we need sdl Using sdl2..   Enum Kind Arrow, Beam, Wait, WaitArrow, Hand, No, CrossHair, SizeNWSE, SizeNESW, SizeWE, SizeNS, SizeAll End   const CURSOR_ARROW:Kind = Kind.Arrow const CURSOR_BEAM:Kind = Kind.Beam const CURSOR_WAIT:Kind = Kind.Wait const CURSOR_WAITARROW:Kind = Kind.WaitArrow const CURSOR_HAND:Kind = Kind.Hand const CURSOR_NO:Kind = Kind.No const CURSOR_CROSSHAIR:Kind = Kind.CrossHair const CURSOR_SIZENWSE:Kind = Kind.SizeNWSE const CURSOR_SIZENESW:Kind = Kind.SizeNESW const CURSOR_SIZEWE:Kind = Kind.SizeWE const CURSOR_SIZENS:Kind = Kind.SizeNS const CURSOR_SIZEEW:Kind = Kind.SizeWE const CURSOR_SIZESN:Kind = Kind.SizeNS const CURSOR_SIZEALL:Kind = Kind.SizeAll   Class SystemCursor method New() _cursors = New Map<Kind, SDL_Cursor Ptr> End method method Set( cursor:Kind ) Local c:SDL_Cursor ptr = _cursors[cursor] If Not c then c = Create( cursor ) _cursors[cursor] = c End SDL_SetCursor( c ) End method   method Restore() Set( CURSOR_ARROW ) End Private field _cursors:Map<Kind, SDL_Cursor Ptr> method Create:SDL_Cursor Ptr( cursor:Kind ) Local cur:SDL_SystemCursor Select cursor Case Kind.Arrow cur = SDL_SYSTEM_CURSOR_ARROW Case Kind.Beam cur = SDL_SYSTEM_CURSOR_IBEAM Case Kind.Wait cur = SDL_SYSTEM_CURSOR_WAIT Case Kind.CrossHair cur = SDL_SYSTEM_CURSOR_CROSSHAIR Case Kind.WaitArrow cur = SDL_SYSTEM_CURSOR_WAITARROW Case Kind.No cur = SDL_SYSTEM_CURSOR_NO Case Kind.Hand cur = SDL_SYSTEM_CURSOR_HAND Case Kind.SizeNWSE cur = SDL_SYSTEM_CURSOR_SIZENWSE Case Kind.SizeNESW cur = SDL_SYSTEM_CURSOR_SIZENESW Case Kind.SizeWE cur = SDL_SYSTEM_CURSOR_SIZEWE Case Kind.SizeNS cur = SDL_SYSTEM_CURSOR_SIZENS Case Kind.SizeAll cur = SDL_SYSTEM_CURSOR_SIZEALL End Select Return SDL_CreateSystemCursor( cur ) End method End

and to use:

Monkey

field _cursor:SystemCursor = New SystemCursor 'depends on how your app is set up for the mouse commands method OnMouseEnter() Override _cursor.Set( CURSOR_NO ) End method method OnMouseLeave() Override _cursor.Restore() End method

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field _cursor:SystemCursor = New SystemCursor   'depends on how your app is set up for the mouse commands method OnMouseEnter() Override _cursor.Set( CURSOR_NO ) End method method OnMouseLeave() Override _cursor.Restore() End method

[nerobotParticipant]

Here’s a proper class version of the above for you as well

In what place it’s proper?

1. System cursor is a global thing, so we can manege it the sane way – via global functions. In your case we must create instance or instances.
2. Separated global consts bring some noise in autocompletion, if I would write game for mobiles, I will see them when type cur somewhere.
3. You restore CURSOR_ARROW, but cursor might be not an arrow type.

My class present not a single cursor – it is cursor manager.

[AdamStrangeParticipant]

mmmm, not sure about the cursor and mobile thing. in ‘general’ mobile stuff does not use cursors. Cursors are a desktop thing.

the default cursor IS an Arrow. You are assuming that is ‘could’ be something else. It won’t. it WILL be an arrow. Unless already set by something and not put back to an arrow <- in which case it’s an error and the Arrow should be used.

A control may have different cursors, but the default will always be an arrow. it is up to you to decide, but it should always  be set back to an Arrow.

But… There can be issues with controls not setting the cursor back to the default arrow, and thus affecting the required use in other controls. hence using Arrow as the default.

 

The reason I used ‘proper’ as the use for the class is you are not really using the class. you are using just functions and some globals. you can remove the class entirely and it still functions. So. in this case it is not really a class.

Also you are using globals inside a class, thus breaking the reason for using oop in the first place.

 

in essence you’ve just got a bunch of functions and some globals wrapped up in a class that doesn’t need them. so either write the code to use a class or don’t use a class at all.

 

to quote you:

1. System cursor is a global thing, so we can manege it the sane way – via global functions. In your case we must create instance or instances.

if it is global and accessed by functions then it is functional programming NOT a class. you don’t need a class and are just adding unneeded code.

You really then just update the functions names with something like:

function CursorStore(

function CursorRestore(

etc

 

I’m not sure about the following statement:

Separated global consts bring some noise in autocompletion

 

doesn’t that suggest the possibility that there might be something off with the autocomplete in its operation? I don’t know about that as I don’t use it. But if you need to program something (in a very particular way)  to avoid it doing something… possibly?

 

But as I said, brilliant work, either way

[nerobotParticipant]

Yes, in some cases I use classes just as a container for functions.

It’s convenient way for me – keep all similar functions in one place / scope / entry_point.

[nerobotParticipant]

I was confused to know – there is MouseDevice.Cursor property to deal with system cursors.

[AdamStrangeParticipant]

???? Checked and confirmed in mojo.MouseDevice

tried setting it by using:

Monkey

Mouse.Cursor = MouseCursor.No Mouse.Cursor = MouseCursor.Arrow

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Mouse.Cursor = MouseCursor.No   Mouse.Cursor = MouseCursor.Arrow

and it worked!

[Author]

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