Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!ll-xn!mit-eddie!uw-beaver!ssc-vax!dmg
From: dmg@ssc-vax.UUCP (David Geary)
Newsgroups: comp.sys.amiga
Subject: Re: Mouse Pointer Help Required
Message-ID: <1665@ssc-vax.UUCP>
Date: 8 Feb 88 22:17:31 GMT
Organization: Boeing Aerospace Corp., Seattle WA
Lines: 75
Keywords: Help, Mouse Pointer


In Article 14707, Chuck McManis writes:

>AAAAAAAAAAAAAAAAAAARRRRRRRRRRRRRRRRRRRRRGGGGGGGGGGGGGGGGGGGHHHHHHHHHHHH!
>So close, and yet so far away. The 'clean' approved way of changing your
>pointer to ANYTHING, including 'nothing' is to use the Intuition 
>SetPointer call. To restore it to the original preferences set pointer
>you can use the Intuition ClearPointer() call. BUT THERE IS A GOTCHA!
>And a very important one it is. The data you pass to SetPointer(), and
>read my lips here, MUST BE IN CHIP RAM OR YOU WILL GET AN UGLY SMEAR
>ON SYSTEMS WITH FAST RAM.

>So, the appropriate code would be something like ...

>UWORD	*Newpointer = NULL;

>GoAwayPointer()
>{
>  if (!NewPointer) NewPointer = AllocMem(2*sizeof(UWORD),MEMF_CHIP+MEMF_CLEAR);
>  SetPointer(NewPointer,1,1,1,1);
>}
>
>ComeBackPointer()
>{
>  ClearPointer();
>}

>Note also that the pointer is a sprite and follows the rules for sprite 
>images, meaning that each plane is represented by "n" UWORDs where n is
>the number of lines high the new image is, and that you have to have 
>2 planes because a sprite is 3 colors (plus transparent). So 1 * 2 = 2
>UWORDs. Finally, set the hotspot to 1,1 because if you set it to 0,0
>SetPointer sometimes activates sprite 1 (for no apparent reason).

Almost...

The call to SetPointer should read:

SetPointer(w, NewPointer,1,1,1,1);  - You must send SetPointer a pointer to
				      the window you want to change the
				      pointer in.

Also, this still leaves you with a pointer - even if it is just one pixel
wide, and one pixel high.  The third and fourth args to SetPointer give
it a new location for the pointer.  However, they are OFFSETS from the
current pointer position, so if you wanted to put the one-pixel ptr
at 0,0, you would:

SetPointer(w, NewPointer,-(s->MouseX),-(s->MouseY),1,1);

You could even try to put it offscreen like so:

SetPointer(w, NewPointer,-(s->MouseX+1),-(s->MouseY+1),1,1);

Note that I have tried the method of putting pointer at 0,0, cause
that's what I want to do for my application.  I've never tried
to put it offscreen, but try it if you want...

BTW, s above is a pointer to the screen your window's in...


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~	"... Who's gonna see that I'm fed,		~
~	     And who's gonna want me in bed,		~
~	     But who'll watch TV instead, 		~
~	     Because I do..."				~
~							~
~		If Not You, Dr. Hook			~
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


-- 
***********************************************************
* David Geary, Boeing Aerospace Co., Seattle, WA 	  *
* (206)773-5249.  --I disclaim everything I've ever said--*
***********************************************************