Path: utzoo!mnetor!tmsoft!torsqnt!jarvis.csri.toronto.edu!cs.utexas.edu!rutgers!cbmvax!ken
From: ken@cbmvax.commodore.com (Ken Farinsky - CATS)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Clipping? Questions and recommendations.
Message-ID: <9993@cbmvax.commodore.com>
Date: 5 Mar 90 18:07:05 GMT
References: <1990Mar3.110330.6134@utu.fi>
Reply-To: ken@cbmvax (Ken Farinsky - CATS)
Organization: Commodore, West Chester, PA
Lines: 89

In article <1990Mar3.110330.6134@utu.fi> sutela@utu.fi (Kari Sutela) writes:
>Basically, I'd like to see your opinions on the best method for performing
>clipping. I understand Intuition windows perform clipping automatically. Is
>this true regardless of the window type (SIMPLEREFRESH etc.)?

GimmeZeroZero windows will slow down the whole intuition interface once
you open a few of them.  Use the user clip rects, which were added in
1.2.  The following is a excerpt from the Addison Wesley RKM, Libs & Devs,
this should work (if I cut it correctly):

Here is some sample code for clipping windows:

/*-----------------------------------------------------------------
** UnclipWindow()
**
** routine to remove a clipping region installed by ClipWindow() or
** ClipWindowToBorders(), disposing of the installed region and
** reinstalling the region removed.
*/
void UnclipWindow(struct Window *win, struct Region *prev_region)
{
register struct Region     *old_region ;

/* remove any old region by installing a NULL,
** then dispose of the old region if one was there.
*/
if (NULL != (old_region = InstallClipRegion(win->WLayer, prev_region)))
    DisposeRegion(old_region) ;
}

/*-----------------------------------------------------------------
** ClipWindow()
** clip a window to a specified rectangle (given by upper left and
** lower right corner.  the removed region is returned so that it
** can be re-installed later.
*/
struct Region *ClipWindow(struct Window *win,
               LONG minX, LONG minY, LONG maxX, LONG maxY)
{
register struct Region     *new_region ;
register struct Region     *old_region ;

struct Rectangle    my_rectangle ;

/* set up the limits for the clip */
my_rectangle.MinX = minX ;
my_rectangle.MinY = minY ;
my_rectangle.MaxX = maxX ;
my_rectangle.MaxY = maxY ;

/* get a new region and OR in the limits. */
new_region = NewRegion() ;
OrRectRegion(new_region, &my_rectangle) ;

/* install the new region, and dispose of any existing region */
return(InstallClipRegion(win->WLayer, new_region));
}

/*-----------------------------------------------------------------
** ClipWindowToBorders()
** clip a window to its borders.
** the removed region is returned so that it can be re-installed later.
*/
struct Region *ClipWindowToBorders(struct Window *win)
{
register struct Region     *new_region ;
register struct Region     *old_region ;

struct Rectangle            my_rectangle ;

/* set up the limits for the clip */
my_rectangle.MinX = win->BorderLeft - 1 ;
my_rectangle.MinY = win->BorderTop - 1 ;
my_rectangle.MaxX = win->Width - win->BorderRight ;
my_rectangle.MaxY = win->Height - win->BorderBottom ;

/* get a new region and OR in the limits. */
new_region = NewRegion() ;
OrRectRegion(new_region, &my_rectangle) ;

/* install the new region, and dispose of any existing region */
return(InstallClipRegion(win->WLayer, new_region));
}

-- 
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Ken Farinsky -- CATS               Commodore Business Machines
PHONE 215-431-9421         UUCP  ...{uunet,rutgers}!cbmvax!ken
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